ENDODONTICS-Endodontics in Clinical Practice, 6e

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Harty’s endodontics in clinical practice

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Commissioning Editor: Alison Taylor
Development Editor: Fiona Conn
Project Manager: Mahalakshmi Nithyanand
Designer/Design Direction: Charles Gray
Illustration Manager: Bruce Hogarth
Illustrator: Antbits

Harty’s endodontics
in clinical practice

Sixth edition

Edited by
Bun San Chong BDS (Lond), MSc. (Lond), PhD (Lond), LDS RCS (Eng),

FDS RCS (Eng), MFGDP (UK), MRD
Specialist in Endodontics
London, UK
Illustrations by
Antbits

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Edinburgh  London  New York  Oxford  Philadelphia  St Louis  Sydney  Toronto  2010

First Edition published 1976
Second Edition published 1982
Third edition published 1990
Fourth edition published 1997
Fifth edition © 2004, Elsevier Science Limited
Sixth edition © 2010, Elsevier Limited. All rights reserved.

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ISBN 978 0 7020 3156 4

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Notice
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mended dose or formula, the method and duration of administration, and contraindications. It is the responsibility of the
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Preface

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The new edition of this long-established book has come full circle, back to where it began. Fred
Harty, after whom this book is named, was responsible for the first three editions and I have been
a specialist in endodontics for over 20 years in the practice founded by Fred.

Tom Pitt Ford was responsible for the fourth and fifth editions of this book. We had other plans
for further collaboration but, unfortunately, Tom passed away in the early stages of this project and
so this edition is dedicated to him as a fitting tribute.

Tom was the Professor of Endodontology, Vice-Dean of King’s College London Dental Institute
at Guy’s, King’s College and St Thomas’ Hospitals, and previously Director of Education. He was
also Director of Institutional and Academic Audit at King’s College, London. A man of extraordinary
talent, Tom’s death is an irreplaceable loss to dentistry and in particular the specialty of endodontics.
Clinician, teacher, researcher, author and administrator, Tom’s roles were numerous and his con-
tributions to advancing endodontics immeasurable. Those privileged to have trained or worked
with him, including many of the contributors to this edition, will forever remember and admire
his example of diligence, perseverance and attention to detail.

The aim of this book is for it to be an authoritative guide to proven, current clinical endodontic
practice. It is primarily intended as an essential undergraduate text for dental students in the United
Kingdom. Since it is imperative that practitioners keep up to date, continuing education is now a
mandatory requirement, so the book is also intended for dental practitioners seeking to update
their knowledge, to help and support especially those who have chosen to embark on continuing
education courses.

Despite the recognition and the establishment of a specialist list in endodontics in the United
Kingdom, endodontic treatment will continue to be carried out mostly in general dental practice.
Students and new graduates should not only be competent in treating the majority of endodontic
cases but also be able to recognize, where appropriate, the need for referral to a specialist. A growing
number of patients can now benefit from management of challenging or complex endodontic treat-
ment by specially trained practitioners and can expect to receive a predictable outcome.

Diagnosis is the first step in the care and management of any patient so a new chapter on this
topic is included in this edition. The style of referencing has also been replaced with the Vancouver
system so that it is unobtrusive and easy to read. Illustrations, including line artwork, are now in
full colour.

It is inevitable that there will be some duplication of material in this book and this should be
viewed as reinforcement of relevant information. Different contributors will also have different
writing styles and preferred terminology but, hopefully, not at the expense of clarity and
cohesion.

I am grateful to all the contributors for providing their perspective on the topics covered in this
new edition. I would also like to thank the publishers. I acknowledge the patience and understand-
ing of my family, Grace, James and Louisa.

B.S. Chong
2009

v

Dedicated to
Professor Thomas Russell Pitt Ford
BDS (Lond), LDS RCS (Eng), PhD (Lond),

FDS RCPS (Glas), FDS RCS (Eng), FDS RCS (Edin)
1949–2008

Contributors

Nicholas P. Chandler BDS, MSc., PhD, LDS RCS (Eng), Dag Ørstavik Cand Odont, Dr Odont.
Professor of Endodontics,
FDS RCPS (Glas) FDS RCS (Edin), FFD RCSI Institute of Clinical Dentistry, University of Oslo, Oslo,
Associate Professor of Endodontics, Norway
School of Dentistry, University of Otago, Dunedin,
New Zealand Shanon Patel BDS, MSc., MClinDent, MFDS RCS (Eng),

Bun San Chong BDS, MSc., PhD, LDS RCS (Eng), MRD RCS (Edin)
Specialist in Endodontics,
FDS RCS (Eng), MFGDP (UK), MRD Dental Institute, King’s College London, London, UK
Specialist in Endodontics,
London, UK Heather E. Pitt Ford LDS RCS (Eng), FDS RCS (Eng)
Associate Specialist in Paediatric Dentistry,
Henry F. Duncan BDS, MClinDent, MRD RCS (Edin), Dental Institute, King’s College London, UK

FDS RCS (Edin) John D. Regan BDentSc., MSc., MS
Lecturer/Consultant in Endodontics, Honorary Associate Professor,
Dublin Dental School & Hospital, Trinity College Dublin, Baylor College of Dentistry, Texas A & M University System,
Dublin, Ireland Dallas, Texas, USA

Michael P. Escudier MBBS, BDS, FDS RCS, FDS (OM) John S. Rhodes BDS, MSc., MFGDP (UK),

RCS (Eng), FFGDP (UK) MRD RCS (Edin)
Senior Lecturer/Honorary Consultant in Oral Medicine, Specialist in Endodontics,
Dental Institute, King’s College London, UK Poole, Dorset, UK

Massimo Giovarruscio DDS Ilan Rotstein DDS
Specialist in Endodontics, Rome, Italy Professor of Endodontics,
Chair, Surgical Therapeutic and Bioengineering Sciences,
James L. Gutmann DDS, Cert Endo, PhD, FICD, Associate Dean, Continuing Oral Health
Professional Education,
FACD, FADI University of Southern California School of Dentistry
Professor Emeritus, Baylor College of Dentistry, Texas A & M Los Angeles, California, USA
University System, Dallas, Texas, USA
James H.S. Simon BA, DDS
Francesco Mannocci MD, DDS, PhD Professor of Endodontics, Director, Advanced
Senior Lecturer/Honorary Consultant in Endodontology, Endodontic Program,
Dental Institute, King’s College London, UK University of Southern California School of Dentistry
Los Angeles, California, USA
Philip J.C. Mitchell BDS, LDS RCS (Eng), MSc.,
Andrew D.M. Watson BDS, MSc., DGDP (UK), MRD
MRD RCS (Edin) Specialist in Endodontics, Cheshire, UK
Senior Specialist Clinical Teacher/Specialist in Endodontics,
Dental Institute, King’s College London, UK

Amanda L. O’Donnell BDS, MFDS (Eng), MClin Dent,

MPaedDent, FDS RCS (Eng)
Consultant in Paediatric Dentistry,
UCL Eastman Dental Institute, London, UK

vii

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Contents

Contents

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Preface ........................................................................ v   3 Diagnosis ....................................................... 17
List of contributors ................................................. vii S Patel & BS Chong
Summary ................................................. 17
  1 Introduction & overview .............................. 1 Introduction ........................................... 17
BS Chong History .................................................... 18
Summary ................................................... 1 Examination ........................................... 18
Introduction ............................................. 1 Investigations........................................... 21
Modern endodontics................................. 2 Differential diagnosis.............................. 26
Scope of endodontics .............................. 3 Restorability............................................. 28
Role of microorganisms ........................... 3 Treatment options................................... 29
Tissue response to root Specific endodontic treatment
canal infection........................................... 4 options .................................................... 29
Quality assurance ..................................... 4 Learning outcomes.................................. 30
Recent developments ............................... 4 References ............................................... 31
Learning outcomes.................................... 6
References ................................................. 6   4 Pulp space anatomy & access
cavities ............................................................ 35
  2 General and systemic aspects ADM Watson
of endodontics................................................. 9 Summary.................................................. 35
MP Escudier Introduction ........................................... 35
Summary.................................................... 9 Nomenclature ......................................... 36
Introduction ............................................. 9 Accessory and lateral canals .................. 38
Differential diagnosis of dental pain..... 10 Location of apical foramina................... 38
Maxillary sinus ....................................... 11 Variations in pulp space anatomy ........ 38
Systemic disease and endodontics......... 11 Effects of tertiary dentine on
Use of antibiotics in endodontics.......... 13 pulp space................................................ 39
Control of pain and anxiety................... 14 Pulp space anatomy and
British National Formulary ................... 15 access cavities........................................... 40
Learning outcomes ................................. 15 Pulp space anatomy of
References ............................................... 15 primary teeth .......................................... 49

ix

Contents

Apical closure ......................................... 50   7 Preparation of the root canal system ...... 97
Learning outcomes ................................. 51 JS Rhodes
References ............................................... 51 Summary ................................................. 97
Introduction ........................................... 97
  5 Maintaining dental pulp vitality .............. 55 Gaining access to the root
HF Duncan canal system ............................................ 98
Summary ................................................. 55 Working length determination ............ 100
Introduction ........................................... 55 Root canal irrigation ............................ 101
Pulp-dentine complex ............................ 55 Instrumentation techniques ................ 102
Pulp response to irritants ...................... 56 Controversies in root canal
Pulpal irritants ........................................ 56 cleaning and shaping ........................... 105
Management of deep caries ................... 59 Learning outcomes ............................... 107
Management of pulp exposure ............. 60 References ............................................. 107
Regenerative developments ................... 60
Pulp response and maintaining   8 Intracanal medication ................................ 111
pulp vitality ............................................ 63 D Ørstavik
Learning outcomes ................................. 64 Summary ................................................ 111
References ............................................... 64 Introduction ......................................... 112
History .................................................. 112
  6 Basic instrumentation in endodontics ... 71 Rationale and overview of
BS Chong applications .......................................... 112
Summary ................................................. 71 Microbiology of endodontic
Introduction ........................................... 72 infections .............................................. 113
Basic instrument pack............................. 72 Antimicrobial agents ............................ 114
Rubber dam............................................. 72 Resistance of oral microbes to
Instruments for access cavity medicaments ........................................ 116
preparation ............................................. 76 Concept of predictable disinfection
Instruments for root canal in endodontics ..................................... 116
preparation ............................................. 78 Induction of hard tissue formation .... 119
Devices to determine working Pain of endodontic origin ................... 119
length ...................................................... 82 Exudation and bleeding ...................... 120
Irrigant delivery devices.......................... 84 Root resorption .................................... 120
Instruments for retrieving broken Tissue distribution of medicaments.... 120
instruments and posts ........................... 85 Tissue toxicity and biological
Instruments for filling root canals ........ 86 considerations ...................................... 121
Storage and sterilization of Suggested clinical procedures .............. 121
endodontic instruments.......................... 90 Learning outcomes .............................. 123
Loupes, fibre-optic lights and References ............................................ 123
operating microscopes ........................... 91
Learning outcomes ................................. 91   9 Root canal filling ....................................... 131
References ............................................... 92 NP Chandler
Summary ............................................... 131

x

Contents

Introduction ......................................... 131 Treatment of primary teeth ................ 198
Canal anatomy .................................... 132 Learning outcomes ............................... 204
Access and canal preparation ............. 132 References ............................................. 205
Criteria for filling ................................ 132
Materials used to fill root canals ....... 133 12 Endodontic aspects of
Sealers .................................................. 133 traumatic injuries.........................................209
Smear layer .......................................... 135 HE Pitt Ford
Gutta-percha ........................................ 135 Summary ............................................... 209
Other methods of root canal Introduction ......................................... 209
filling .................................................... 146 History, examination and
Coronal restoration .............................. 150 immediate management ...................... 210
Follow-up .............................................. 151 Types of injury ...................................... 211
Treatment outcome .............................. 151 Effects of trauma on the dental
Learning outcomes ............................... 151 tissues .................................................... 212
References ............................................. 151 Management of primary teeth ............ 212
Management of permanent
10 Surgical endodontics ............................... 159 teeth ...................................................... 213
JL Gutmann & JD Regan Root canal treatment of
Summary............................................... 159 immature teeth ..................................... 220
Introduction.......................................... 160 Auto-transplantation of an
Treatment choices ............................... 160 immature premolar into
Indications for periradicular the incisor space .................................. 223
surgery .................................................. 160 Complications ..................................... 223
Preoperative assessment ...................... 161 Orthodontic treatment ....................... 226
Surgical kit ............................................ 161 Learning outcomes .............................. 226
Surgical technique ............................... 162 References ............................................ 226
Periradicular surgery of particular
teeth .......................................................183 13 Marginal periodontitis and
Repair of perforation .......................... 185 the dental pulp ........................................... 231
Replantation/transplantation ............. 186 I Rotstein & JH Simon
Regenerative procedures ..................... 187 Summary ............................................... 231
Treatment outcome – aetiology Anatomical considerations .................. 231
and evaluation ..................................... 188 Effect of inflamed pulp on the
Retreatment of surgical periodontium ...................................... 232
procedures ........................................... 189 Effect of marginal periodontitis
Learning outcomes................................ 190 on the pulp .......................................... 233
References ............................................. 190 Classification ....................................... 233
Complications due to
11 Endodontics in primary teeth ................ 197 radicular anomalies ............................ 242
AL O’Donnell Alternatives to implants ...................... 244
Summary .............................................. 197 Learning outcomes .............................. 248
Introduction ........................................ 197 References ............................................. 250

xi

Contents

14 Problems in endodontic treatment ...... 253 Introduction ........................................ 269
PJC Mitchell Effects of endodontic treatment
Summary .............................................. 253 on the tooth ......................................... 270
Emergency treatment .......................... 253 Survival of the endodontically
Failure of anaesthesia in acute treated tooth ......................................... 270
inflammation ....................................... 255 Timing the restorative procedure ........ 270
Problems with preparation of Restoration choice ................................ 271
the root canal system .......................... 257 Posts ..................................................... 277
Problems with filling of the root Learning outcomes .............................. 285
canal system ......................................... 264 References ............................................ 285
Learning outcomes .............................. 265
References ............................................ 266 Index ...................................................................... 287

15 Restoration of endodontically
treated teeth ............................................... 269
F Mannocci & M Giovarruscio
Summary .............................................. 269

xii

1Chapter  

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Introduction and overview

B.S. Chong

CHAPTER CONTENTS 1 INTRODUCTION
1
Summary 2 Endodontology is the branch of dental sciences concerned
Introduction 3 with the form, function, health of, injuries to and the
Modern endodontics 3 diseases of the dental pulp and periradicular region, and
Scope of endodontics 4 their relationship with systemic well-being and health.
Role of microorganisms 4 Endodontic treatment can be defined as the prevention or
Tissue response to root canal infection 4 treatment of apical periodontitis, the principal disease.
Quality assurance 6 The concept of treating the pulp of the tooth to preserve
Recent developments 6 the tooth itself is a relatively modern development in the
Learning outcomes history of dentistry and it may be useful to review, very
References briefly, the history of pulp treatment in order to appreciate
better modern views on endodontic treatment. Toothache
SUMMARY has been a scourge of mankind from the earliest times.
Both the Chinese and the Egyptians left records describing
The science and art of endodontics has come a long way caries and alveolar abscesses. The Chinese believed that
since the early days. A brief review of the history of endo- these abscesses were caused by a white worm with a black
dontics is helpful in understanding its influence on current head which lived within the tooth. The ‘worm theory’ was
practice. The scope of modern endodontics is now wider current until the middle of the eighteenth century when
and encompasses a variety of procedures. Patients are no doubts were raised,1 but they could not be expressed for-
longer willing to accept tooth loss and have higher treat- cibly because those in authority still believed in the worm
ment and care expectations. Microorganisms have an theory.2 The Chinese treatment for an abscessed tooth was
essential role in the pathogenesis of pulpal and periapical aimed at killing the worm with a preparation that con-
diseases. The host defence response against root canal tained arsenic. The use of this drug was taught in most
infection includes numerous inflammatory mediators dental schools as recently as the 1950s in spite of the
and a range of cells. Continuing research is increasing our realization that it was self-limiting and that extensive
knowledge of the root canal microbiota, which will hope- tissue destruction occurred if even minute amounts of the
fully result in dedicated strategies to manage the different drug leaked into the soft tissues. Pulp treatment during
types of root canal infection. Advances in endodontics are Greek and Roman times was aimed at destroying the pulp
continuing and many recent developments have been suc- by cauterization with a hot needle or boiling oil, or with
cessfully translated into everyday clinical practice. a preparation containing opium and hyoscyamus. About
the end of the first century AD, it was realized that pain
could be relieved by drilling into the pulp chamber to
obtain drainage. In spite of modern antibiotics, there is

© 2009 Elsevier Ltd, Inc, BV 1
DOI: 10.1016/B978-0-7020-3156-4.00004-8

Harty’s endodontics in clinical practice

still no better method of relieving the pain of an abscessed not allow their dentists to mutilate their dentitions.
tooth than drainage. Alternatively, it could be that these practitioners were
not so readily swayed by fashion as were their British
Endodontic knowledge remained static until the six- colleagues.
teenth century when pulpal anatomy was described. Until
the latter part of the nineteenth century, root canal therapy MODERN ENDODONTICS
consisted of alleviating pulpal pain and the main function
of the opened root canal was to provide retention for a The re-emergence of endodontics as a respectable branch
dowel crown.3,4 At the same time, bridgework became of dental science began in the 1930s.11,12 The occurrence
popular and many dental schools taught that no tooth and degree of bacteraemia during tooth extraction was
should be used as an abutment unless it was first devital- shown to depend on the severity of periodontal disease
ized.5 Root canal therapy became commonplace partly for and the amount of tissue damage at operation. The incon-
these reasons and also because the discovery of cocaine gruity between microbiological findings in the treatment
led to painless pulp extirpation. The injection of 4% of chronic oral infection and the histological picture was
cocaine as a mandibular nerve block was first reported in demonstrated. When the gingival sulcus was disinfected
1884;4 and 20 years later, the first synthetic local anaes- by cauterization before extraction, microorganisms could
thetic, procaine was produced. Around this time, reports not be demonstrated in the bloodstream immediately
of endodontic surgery appeared.6 The first radiograph of postoperatively.
teeth was taken in 1896,3,7 shortly after the discovery of
X-rays by Roentgen in 1895. This further popularized root Gradually, the concept that a ‘dead’ tooth, one without
canal therapy and gave it some respectability. About the a pulp, was not necessarily infected began to be accepted.
same time dental manufacturers began to produce special Further, it was realized that the function and usefulness of
instruments, which were used primarily to remove pulp the tooth depended on the integrity of the periodontal
tissue or clean debris from the canal. There was no concept tissues and not on the vitality of the pulp.13 Another
of filling the root canals since the object of the procedure important advance was clarification of the ‘hollow tube’
was to provide retention for a post crown. theory14 by research using sterile polyethylene tube
implants in rats.15,16 The tissue surrounding the lumina of
By 1910 ‘root canal therapy’ had reached its zenith and clean, disinfected tubes, which were closed at one end, was
no self-respecting dentist would extract a tooth. Every root relatively free of inflammation and displayed a normal
stump was retained and a crown constructed. Sinus tracts capacity for repair. When such tubes were filled with
often appeared and were treated by various ineffective muscle, the inflammatory reaction was only severe around
methods for many years. The connection between the the openings of the tubes containing tissue contaminated
sinus tract and the pulpless tooth was known but not acted with Gram-negative cocci. These findings place stress on
upon. In 1911, William Hunter8,9 attacked ‘American the microbial contents of the tube; if the tube contains
dentistry’ and blamed bridgework for several diseases of microorganisms then the potential for repair is far less
unknown aetiology. He reported recovery from these con- favourable than when the lumen of the tube is clean
ditions in a few patients following extraction of their teeth. and sterile.17 This infected situation is likely to be found
It is interesting to note that he did not condemn root canal in most root canals requiring treatment. The concept
therapy itself but rather the ill-fitting bridgework and the that ‘apical seal’ was important led to the search for
sepsis that surrounded it. About this time microbiology filling and sealing materials that were stable, non-
became established and the findings of microbiologists irritant and provided a perfect seal at the apical foramen.
added fuel to the fire of Hunter’s condemnations. Radio­ With the more recent realization of the importance of
graphy, which at first helped the dentist, now provided coronal leakage18,19 and the biodegradation of root canal
irrefutable evidence of apical periodontitis surrounding fillings, total filling of the root canal space, including
the roots of pulpless teeth. lateral and accessory canals, has assumed much greater
importance.
Whilst the theory of ‘focal infection’ was not enunciated
by Billings10 until 1918, Hunter’s condemnations started Until relatively recently, practitioners were preoccupied
a reaction to root canal therapy, and there began the with a mechanistic approach to root canal treatment and
wholesale removal of both non-vital and perfectly healthy to the perceived effects of various potent drugs on the
teeth. The blame for obscure diseases was placed on the microorganisms within the root canal rather than a total
dentition, and as dentists could not refute this theory, antimicrobial approach of effective cleaning, adequate
countless mouths were mutilated. Naturally, not all den- shaping and complete filling of the root canal space.20
tists accepted this wholesale dental destruction. Some, This preoccupation diverted attention from the effects
particularly in continental Europe, continued to save teeth of such drugs on the periapical tissues. Medicaments that
in spite of the focal sepsis theory. It is difficult to know kill microbes may also be toxic to living tissue.21 The
why dentists in continental Europe disregarded this theory
and one explanation may be that their patients equated
the loss of teeth with a loss of virility, and therefore, did

2

Introduction and overview Chapter | 1 |

consequences of such materials passing out of the tooth isms present in root canals.28 This led rapidly to the dem-
into the surrounding vital tissues can be localized tissue onstration that the majority of these microorganisms were
necrosis. These avoidable problems cause distress to anaerobes,29,30 and the realization that canals previously
patients and can lead to litigation. Effective elimination of considered sterile contained anaerobes alone. Further-
microorganisms from root canal system is best achieved more, when traumatized teeth were examined, there was a
by instrumentation combined with irrigation. close correlation between the presence of anaerobic bacte-
ria in the root canal and a periapical radiolucency;30 in the
SCOPE OF ENDODONTICS absence of infection, the necrotic pulp and stagnant tissue
fluids cannot induce or perpetuate a periapical lesion. This
The extent of the subject has altered considerably in the was later demonstrated experimentally in teeth where the
last 50 years. Formerly, endodontic treatment confined pulp tissue had been removed; only in those where the
itself to root canal filling techniques by conventional pulp was infected did periapical inflammation occur.31
methods; even endodontic surgery, which is an extension Although anaerobic culturing of root canals is not a tech-
of these methods, was considered to be in the field of oral nique applicable to everyday clinical practice, the results of
surgery. Modern endodontics has a much wider field22,23 research have provided rational explanations for pulp and
and includes the following: periapical diseases and its treatment.32 Microorganisms,
which previously could not be cultured, and so were
• the differential diagnosis and treatment of orofacial mistakenly considered absent, can now be identified.
Over 50% of the oral microbiota is still uncultivable.33,34
pain of pulpal and periradicular origin However, the use of molecular biology techniques has
enabled the identification of microbes that would be
• prevention of pulpal disease and vital pulp therapy undetectable by conventional culturing techniques.33,35,36
• root canal treatment As knowledge in this area expands, our understanding of
• management of post-treatment endodontic disease the root canal microbiota is changing. The presence of
• surgical endodontics specific or combination of microorganisms and their
• bleaching of endodontically treated teeth implications are yet to be fully appreciated.37
• treatment procedures related to coronal restorations
Most root canal infections contain a mixture of
using a core and/or a post involving the root canal microorganisms with bacteria being the main candidate
space pathogen.30,38,39 It has also been shown that the relative
proportions of different microorganism are determined by
• endodontically related measures in connection with the local environmental conditions.39 Endodontic patho-
gens do not occur at random but are found in specific
crown-lengthening and forced eruption procedures combinations.40 If a selection of microorganisms is inocu-
lated into root canals in fixed proportions, their relative
• treatment of traumatized teeth. numbers will change over time, with a decline in aerobes
and an increase in anaerobes.39 It has also been established
ROLE OF MICROORGANISMS that combinations of microorganisms are more likely to
survive than inocula of single species.38 It is clear that one
The Chinese belief that dental abscesses were caused by species can produce substances that others can metabolize
small organisms, worms, persisted until the eighteenth in order to survive, forming complex ecological and nutri-
century. At the end of the nineteenth century Miller24 tional relationships.32
demonstrated the role of bacteria in root canal infection,
and noted that different microorganisms were found in Microorganisms are normally confined to the root canal
the root canal compared with the open pulp chamber. system in pulpless teeth and exist in two forms:
Shortly afterwards, systematic culturing of root canals
was undertaken.25 Unfortunately, these methods, which • planktonic – loose collections or suspensions within
were potentially so valuable for improving the outcome
of root canal treatment, were used to condemn much of the root canal lumen
the dentistry carried out at the time.9 During the 1930s,
microbiological techniques were used to re-establish the • biofilm – dense aggregate, forming plaques on and
scientific basis of root canal treatment. However, tech-
niques at that time only readily identified aerobic bacteria, within the root canal wall.
and led to confusing results in later clinical studies.26,27
This resulted in clinicians being complacent about the role The intraradicular infection may be divided into three
of microorganisms, and performing treatment simply as a categories:
technical exercise.
• Primary – caused by microorganisms that initially
The development of anaerobic culturing allowed the
identification of many previously unknown microorgan- invaded and colonized the necrotic pulp.

• Secondary – caused by microorganisms that were not

present in the primary infection but were introduced
into the root canal system following dental
intervention.

3

Harty’s endodontics in clinical practice

• Persistent infection – caused by microorganisms exception. In the UK, guidance has been published by
the regulatory body on the standards expected of,47 and
associated with the primary or secondary infection the scope of practice for,48 the whole dental team. The
that managed to survive treatment procedures and European Society of Endodontology has issued quality
nutritional deprivation. guidelines for endodontic treatment.49 It is essential that
dental practices have a quality control system to ensure
It is unusual for microorganisms to be present in periapi- that each step in history, diagnosis and treatment is carried
cal lesions; the host defences prevent them from invading out in a logical and consistent manner. This is to ensure
the periapical tissues.41 However, in certain circumstances a high standard of care and treatment, known as clinical
and with some species, microorganisms may establish governance. Patients are increasingly well informed and
an extraradicular infection, which can be dependent or will not tolerate poor standards, e.g. in sterilization pro-
independent of the intraradicular infection; thankfully, cedures or out-of-date views. In the UK and in line with
the incidence of independent extraradicular infection in many other countries, one of the largest source of dental
untreated teeth is low.42 negligence claims relate to endodontics.50 The dramatic
rise in litigation is a reflection that patients are increasingly
TISSUE RESPONSE TO ROOT prepared to seek redress for any failures regarding their
CANAL INFECTION care or treatment.

The role of infection in the demise of damaged pulps In a recent survey in England of newly qualified dentists
was demonstrated in a classic study by Kakehashi and co- in vocational training to join the National Health Service,
workers in the 1960s,43 and eventually led to a biological most expressed a lack of preparedness with regards to
approach to operative dentistry.44 The presence of micro- complex/molar endodontics, with 66% rating their pre-
organisms, their byproducts or damaged tissue in the root paredness as ‘poor’ and 3% ‘very poor’.51 Those dentists
canal can cause apical periodontitis, typically at the apical who have undertaken further training to become special-
foramen but also around the foramina of any lateral ists are expected to achieve consistently high standards in
or accessory canals or at a fracture. The periapical inflam- diagnosis and treatment. However, general practitioners
mation prevents the spread of infection from the tooth cannot continue to practise in the way that they were
into the alveolar bone, otherwise osteomyelitis would taught at dental school many years ago; they must keep
occur. The inflammatory lesion contains inflammatory up to date and offer referral to an appropriate specialist
mediators and numerous inflammatory cells, e.g. poly- when the treatment required is beyond their skill. This
morphonuclear leucocytes, macrophages, B- and T- change has already occurred in the USA and is spreading
lymphocytes and plasma cells.45 The interaction between to other countries. In the UK, continuing professional
these cells and the antigenic substances from the root development is now mandatory for recertification with the
canal results in the release of a large number of inflamma- regulatory body and practitioners are also required to refer
tory mediators. The inflammatory mediators include patients for further advice or treatment when it is neces-
neuropeptides, the complement system, lysozymes and sary, or if requested by the patient.47
metabolites of arachidonic acid.46 Prostaglandins, leucot-
rienes and cytokines play an important role in the devel- Almost all endodontic procedures can be carried out
opment of periapical lesions.45,46 with a predictable outcome. Root canal treatment has a
reported success rate of over 90%,52,53 even though closer
As long as antigens emerge from the canal foramina, analysis reveals that retreatment of teeth with apical
there will be a continuing inflammatory response, medi- periodontitis is less successful than initial treatment in
ated in a number of different ways. This is a very dynamic teeth without apical periodontitis.52,54 It is essential that
response to rapidly multiplying microorganisms in the individual practitioners monitor their outcomes against
root canal, and may not be readily apparent to the clini- accepted criteria,55 and that their treatment protocols
cian observing a radiograph or a histologist examining a conform to published guidelines.49 Success of treatment
slide of fixed cells. Endodontic treatment is primarily can be measured in different ways56 and should encom-
directed at effective elimination of the microorganisms, pass not only clinical but also radiological evidence.
allowing inflammation to subside and healing to occur.
RECENT DEVELOPMENTS
QUALITY ASSURANCE
The dental pulp may be damaged as a result of caries or
The general public across the world now expect profes- infection consequent to trauma or operative dentistry.
sional people to deliver a high standard of service; den- With a reduced incidence of dental caries, a greater empha-
tistry, and endodontic treatment in particular, is no sis on preventing sports injuries, and the preparation of
smaller cavities combined with better restorative materials

4

Introduction and overview Chapter | 1 |

in operative dentistry, the expectation is a decline in through to canal preparation and filling, the improved
the number of teeth with damaged pulps. However, the vision and illumination afforded by the operating micro-
trend and popularity of ‘cosmetic’ dentistry potentially scope is immensely beneficial.
risks irreversibly compromising the pulp. The degree to
which adhesive restorative materials will be successful in Techniques, and in particular instruments, for prepara-
preventing pulp damage in clinical practice is another tion of root canals has altered substantially in recent
unquantifiable variable. years.74,75 A crown-down concept is now the major
approach to shaping and cleaning the root canals.76 Manu-
Recent progress in the understanding of the cellular and facturers are always introducing, onto the market, newer
molecular processes involved in the dentine/pulp complex instruments for preparation of root canals. The develop-
has heralded a new era of regenerative dentistry.57 The ment of nickel-titanium rotary systems continues una-
media trumpeted research in this field with the assertion bated, coupled with the promise of speed, ease and
that one day everyone will be able to grow a completely efficiency. However, not all claims can be substantiated
new set of teeth. The identification of stem cells in the and any instrument or technique is only as good as the
dental pulp, the bioactive molecules within the dentine operator. Endodontic treatment should always be guided
matrix and specific processes promoting tissue regenera- by biological and evidence-based principles. Speed,
tion will, hopefully, translate into biologically-based ther- expediency and technical wizardry does not guarantee a
apies in everyday clinical practice. The ability to control favourable treatment outcome.
tissue injury, microbial infection, and inflammation will
tip the balance so that instead of necrosis there will be There has been a quiet revolution in endodontic surgery.
regeneration and maintenance of pulpal vitality. Case This treatment modality is no longer a substitute for
reports have appeared on the revascularization of necrotic failure to manage properly the root canal system non-
pulps in immature permanent teeth.58,59 In the new and surgically. The indications for endodontic surgery are
allied field of regenerative endodontics, the ultimate goal reduced and non-surgical retreatment should first be con-
is to replace diseased, damaged or missing pulp tissues sidered. Newer root-end filling materials, among other
with healthy tissues to revitalize teeth.60,61 advances, including developments in surgical armamen-
tarium, the implementation of microsurgical techniques,
The management of persistent infection in previously enhanced illumination and magnification have helped
endodontically treated teeth is challenging.62,63,64 Endo- improve the predictability and outcome of endodontic
dontic pathogens have the capability to adapt, including surgery.77 The use of amalgam as a root-end filling material
the formation of biofilms, in response to changes in the is confined to history with zinc oxide-eugenol materials
root canal environment.65,66 As the breadth of microbial and Mineral Trioxide Aggregate (MTA) now being widely
diversity in the oral cavity has been revealed by molecular used.77 In the first prospective clinical study on the use of
techniques,33 several newly identified species/phylotypes MTA as a root-end filling material, a high rate of success
have emerged as potential pathogens.67 Findings have (92%) was achieved.78 Further development of this novel
revealed new candidate endodontic pathogens, including material, with the unique ability to encourage hard tissue
as-yet-uncultivated bacteria and taxa, which may partici- deposition, has helped promote the use of MTA not only
pate in the mixed infections associated with apical perio- as a root-end filling, but also a perforation sealant and
dontitis in previously treated teeth.61,68 Improved pulp capping agent. Other similar tissue regenerative
knowledge of the microbiota should, eventually, lead to materials are being investigated.
dedicated strategies for managing different types of root
canal infection, including those that are recalcitrant. The advent of implants has led to clinicians being con-
fronted with the decision to either extract a tooth and
Images captured on X-ray films or via digital sensors are place an implant or preserve the natural tooth by root
two-dimensional ‘shadowgraphs’ with inherent problems canal treatment. There are debates about the advantages
of geometric distortions and anatomical noise.69 Cone of implants versus endodontics79,80,81 fuelled by the myopic
Beam Computed Tomography (CBCT) is a relatively new perception within both camps that one discipline is a
imaging technique.70 It is designed to overcome some of threat to the other. This has led to the movement to incor-
the deficiencies of conventional radiography.71 CBCT pro- porate implant placement into endodontic surgery. In
duces undistorted and accurate images of the area under reality, both disciplines are complementary to each
investigation enhancing diagnosis and in the process other.82 Endodontic treatment of a tooth represents a fea-
aiding, for example, the planning of endodontic surgery sible, practical and economical way to preserve function
and the management of resorption lesions. Since CBCT is in a vast array of cases and in selected situations in
able to detect lesions that are not discernible on conven- which prognosis is poor, a dental implant is a suitable
tional radiographs, it should also enable more objective alternative.83
assessment of healing after endodontic treatment.
The importance of good coronal restoration of root-
Since its introduction, the use of the operating micro- filled teeth has been highlighted.18,19 This is facilitated by
scope in endodontics has increased72 and it has become the use of adhesive materials where appropriate, and the
an invaluable tool.73 From diagnosis to canal location, placement of suitable bases, and well-fitting restorations.

5

Harty’s endodontics in clinical practice

Despite conflicting arguments about the relative impor- High quality endodontic treatment will make a significant
tance between the quality of the root filling and the contribution to good oral health.
coronal restoration on treatment outcome, there can be
no disagreement that both should be performed well84,85,86 LEARNING OUTCOMES
and are mutually beneficial to the long-term prognosis of
the root treated tooth.52,87 At the end of this chapter, readers will be able to under-
stand and discuss the:
A majority of endodontic treatment is within the capa-
bility of general practitioners but there will, inevitably, be • history of endodontics and its influence on current
cases that are best managed by specialists. Endodontic
referral practice is undertaking more root canal retreat- practice;
ment because of technical deficiencies in the original treat-
ment. In many cases, this is difficult and challenging but • scope of modern endodontics;
success can be very rewarding, particularly when in the • essential role of microorganisms in the pathogenesis
past, the alternative would have been extraction. It is
encouraging that many more patients are refusing to allow of pulpal and periapical diseases;
a tooth with an exposed or infected pulp to be extracted,
but instead ask for it to be saved by root canal treatment. • tissue response to root canal infection;
• high standard of endodontic care and treatment

expected by patients;

• recent developments in endodontics.

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endodontic imaging: Part 1. Endodontics versus implantology:

8

2Chapter  

General and systemic aspects of endodontics

M.P. Escudier

CHAPTER CONTENTS 9 odontogenic and non-odontogenic origin. The potential
9 influence of a number of systemic conditions and dis­
Summary 10 orders, as well as medication, on treatment planning and
Introduction 10 management of endodontic patients will be discussed.
Differential diagnosis of dental pain 10 Sections on the use of antibiotics and analgesics in endo-
10 dontic cases have also been included.
Pain history 11
Examination 11 INTRODUCTION
Persistent orofacial pain 12
Maxillary sinus The treatment of periapical infection using modern endo-
Systemic disease and endodontics 12 dontic techniques is safe and effective, provided it is
Endodontics and infective endocarditis appropriately applied and undertaken by competent clini-
Endodontics in patients with prosthetic 12 cians. In line with this, a full assessment of both the
hip joints medical history and the clinical situation should be under-
Endodontics in patients taking warfarin 13 taken prior to commencing treatment. Comprehensive
or corticosteroids 13 and sensible treatment planning based on a careful analy-
Endodontics in patients taking 14 sis of the information gathered will help to protect
bisphosphonates 14 the patient from harm and the dental practitioner from
Use of antibiotics in endodontics 15 criticism, legal or otherwise.
Control of pain and anxiety 15
Analgesics 15 The dental practitioner is largely dependent on the
British national formulary medical history to identify systemic disease or therapy
Learning outcomes that may affect patient management. It is, therefore,
References vital that this is comprehensive and regularly updated.
In addition, any areas of uncertainty or concern should
SUMMARY be discussed with the patient’s physician prior to com-
mencing treatment. Many patients have systemic disor-
A patient’s general health may have an impact on endo- ders, which are well-controlled by therapy and, therefore,
dontic treatment. In addition, pain is the predominant unlikely to influence the outcome of dental treatment.
complaint associated with endodontic disease. This However, the therapy itself may influence their manage-
chapter will cover the diagnosis of orofacial pain of both ment, for example patients taking prednisolone or
warfarin.

The assessment will initially consist of the history and
a clinical examination, which will provide a differential
diagnosis. It should be remembered that the history is the

© 2009 Elsevier Ltd, Inc, BV 9
DOI: 10.1016/B978-0-7020-3156-4.00005-X

Harty’s endodontics in clinical practice

single most important factor in arriving at a diagnosis.1 Table 2.1  Pain history
However, the clinical examination and subsequent inves-
tigations will increase the clinician’s confidence in the Duration When did your pain start?
diagnosis, even though they may contribute relatively few Have you ever had a pain like this
new facts.2 The fear of transmission of HIV (human immu- before?
nodeficiency virus) or hepatitis viruses as well as prions
has highlighted the importance of applying current guide- Character What type of pain is it?
lines for cross-infection control in endodontics as in any
other aspect of clinical dentistry.3 Periodicity When do you get the pain?

DIFFERENTIAL DIAGNOSIS Does it come and go?
OF DENTAL PAIN
Is there any particular pattern to the
The commonest cause of pain in the orofacial region pain?
is dental disease leading to pulpal pain (see Chapter 3).
As such, dental surgeons are experienced and competent Severity How severe is your pain?
in the diagnosis and management of this complaint.
However, the differential diagnosis of pain in the teeth, Site Where is your pain?
jaws and face is far wider than is sometimes appreciated.
Pain may be: Radiation Does your pain spread to other
areas?
• referred from a distant origin, e.g. cardiac
• have an unusual local cause, e.g. osteomyelitis Provoking factors Does anything make your pain
• psychogenic in origin, e.g. atypical facial pain worse?
• neurological, e.g. trigeminal neuralgia
• modified by apparently unrelated factors, e.g. Relieving factors Does anything make your pain
better?
previous cerebrovascular accident.
Associated factors Have you noticed anything else
This broader diagnostic sieve should be remembered, about your pain?
particularly if the pattern of presentation is unusual, the
examination findings are sparse or conflicting, or if folds. Observation of the patient’s face during the history
pain persists or develops in spite of, apparently, successful taking may reveal a subtle neurological feature requiring
treatment. The essence of good clinical practice is a formal assessment of cranial nerve function. An assess-
methodical and disciplined approach (history, followed ment of the level of pain can be made using the facial
by examination, followed by special investigations – expression,5 although it is important to remember that
usually radiographic, followed by analysis and conclu- facial expressions can be manipulated. Hence avoidance
sion). In the case of orofacial pain this is extremely well of, or flinching from, examination may be a more accurate
dealt with in other texts.4 indication of a trigger spot or tenderness than response to
questioning during examination. The observation of man-
Pain history dibular movements is the essential preliminary to exami-
nation of temporomandibular joint function.
A thorough, structured pain history will provide a diagno-
sis in the majority of cases and will help identify those areas The features of a comprehensive examination of the
in need of further investigation. This should commence teeth and jaws are described in Chapter 3. The soft tissues
with the patient being asked to describe the pain in their of the cheeks, palate, tongue and floor of the mouth may
own words, before asking direct questions. Certain, core also yield vital, relevant information. The necessity of a
information (Table 2.1) should be elicited in all cases.4 detailed occlusal examination depends on the history and
clinical setting. Similarly, the history will determine the
Examination necessity or desirability of formal assessment of the tem-
poromandibular apparatus. The maxillary sinus as a cause
The assessment of a patient starts with their entry into the of pain is considered below. Thermal or electrical stimula-
clinical setting. This will enable observation of the general tion of suspect teeth, differential local anaesthetic injec-
demeanour as well as any locomotor problems, walking tions, and removal of restorations all have their place in
aids or possible neurological deficits. It may enable iden- diagnosis. In addition, radiography is essential, but all
tification of a facial swelling, and particular attention these techniques must supplement the history and clinical
should be paid to facial symmetry, notably that of the examination, and never replace them.
cheeks, the mandibular angle region and the nasolabial
Persistent orofacial pain

The orofacial region (including the teeth) is a common
site for the expression of pain or discomfort as a manifes-

10

General and systemic aspects of endodontics Chapter | 2 |

tation of underlying psychosocial disharmony. It may be of benefit.7 However, the clinician will need to weigh
represent anything from a plea for help to a symptom of the small benefits of the antibiotic treatment against the
frank psychosis. The dental surgeon should avoid being potential for adverse effects at both the individual and
manipulated by the patient, or their relatives, into under- general population levels.7 Periapical infection of premo-
taking treatment when the diagnosis is uncertain or the lar or molar teeth may lead to purulent discharge into the
evidence conflicting. In such circumstances, it is better to sinus with associated pain. A further consideration is the
defer active treatment until a definitive diagnosis can be risk of penetration of the sinus wall or even the sinus
obtained. In many such cases, the pain will either resolve lining by endodontic instruments, or during apical surgery.
spontaneously or provide further evidence to assist in the This may result in acute sinusitis from bacterial contami-
diagnosis, e.g. development of a hemifacial rash of herpes nation. The condition may resolve spontaneously but the
zoster. A review appointment should be arranged with the prescription of a broad-spectrum antibiotic and nasal
caveat that the patient may return sooner should the need decongestant (see below) is usual practice.
arise. The dental practitioner also has the opportunity to
refer the patient for a second opinion at any time, particu- Small oroantral communications usually heal sponta-
larly where the diagnosis continues to remain unclear. neously, and in the case of apical surgery, the replacement
of the surgical flap is sufficient to seal the opening. The
Certain features in the history often help in the diagno- identity of microorganisms involved in sinus infection is
sis of idiopathic facial pain. The pain is often unremitting often unclear and broad-spectrum antibiotics may be
and may have been present for months or even years. The required, e.g. amoxicillin 500 mg, three times a day. It is
stated severity may be out of proportion to the observed usual to continue therapy for 5 days although a one-off
level of distress, disturbance of life or self-therapy. The 3g dose of amoxicillin is equally effective. If there is poor
pain may not follow anatomical boundaries and may be drainage of the sinus, e.g. a history of chronic sinusitis,
described as throbbing, nagging, aching, miserable or nasal drops (0.5% ephedrine) should be prescribed. In
cruel in nature. It does not usually disturb sleep, although addition, inhalations, such as menthol and eucalyptus,
there may be a coincident disturbance of sleep pattern. In have a soothing effect and may be of benefit.
addition, other chronic pain conditions such as headache,
low back pain and abdominal or pelvic pain are often A connection between sinus disease and root canal
present. There may also be obvious secondary gain (family treatment was reported. They relate to aspergillosis of the
or social) for the sufferer. In such cases it is important to maxillary antrum following root canal treatment with
seek further information in relation to the patient’s social zinc-oxide based cements that are known to promote
history and family circumstances. There is often a history cultures of the fungus Aspergillus.8,9,10
of long-term or recent distressing life events, e.g. bereave-
ment, divorce or job loss.4 SYSTEMIC DISEASE AND
ENDODONTICS
Depression is common in chronic pain patients and
may be effectively detected by two simple questions:6 Disabled or debilitated patients cannot be expected to
‘during the last month have you often been bothered by readily tolerate complex and lengthy treatment proce-
feeling down, depressed or hopeless?’ and ‘during the past dures. However, even in severe ill-health, some patients
month have you been bothered by having little interest or have a strong desire to retain their natural teeth, and the
pleasure in doing things?’ Psychiatric treatment or psycho- dentist’s duty is to try to respond. Even in terminal illness,
therapy is often beneficial and may be curative. Such cases simple treatment can be a great aid to comfort, masticatory
are often best referred to an oral physician as direct referral function and morale. Good decision-making is dependent
to a psychiatrist may meet with difficulties. on frank and thoughtful discussion with the patient
and his medical advisers. In some conditions, e.g. cardiac
MAXILLARY SINUS abnormalities, endodontic treatment should only be
carried out if a high standard of treatment can be achieved,
The close proximity of the maxillary sinuses to the maxil- which may involve referral to a specialist.
lary teeth can make the diagnosis of pain in these seg-
ments difficult. The distinction between pain of dental Both the patient’s general prognosis and the prognosis
origin and sinusitis may be helped by the presence of for the tooth being treated must be considered; this may
obvious dental disease, or a typical acute or recurrent lead to the decision to extract the tooth rather than under-
sinusitis with nasal discharge. Acute sinusitis rarely occurs take root canal treatment. In chronic diseases, subject
without preceding symptoms of ‘a cold’, and tenderness to cyclical remission, either spontaneously or with treat-
to pressure of a whole quadrant of teeth is characteristic. ment, it is sensible to defer dental intervention until the
In such cases, the use of broad-spectrum antibiotics, e.g. optimum physical health is achieved. This is particularly
amoxicillin 500 mg, three times a day for 7–14 days, may true of haematological disorders, e.g. leukaemia, espe-
cially if the patient receives periodic transfusion or cycles

11

Harty’s endodontics in clinical practice

of chemotherapy. Sufferers from haemorrhagic diatheses • any episodes of infection should be investigated and
will not require factor replacement or antifibrinolytic
therapy for root canal treatment alone, but may do if a treated promptly to reduce the risk of endocarditis
local anaesthetic is to be given or endodontic surgery developing.
undertaken. In all such cases, the patient’s haematologist
should be consulted to discuss any necessary preoperative NICE also recommended that healthcare professionals
or perioperative measures. There is insufficient evidence should offer people at risk of infective endocarditis
to show that the presence of systemic disease has a major clear and consistent information about prevention; these
influence on the healing of periapical lesions. Hence, a include:
positive approach should be taken to treatment even in
immunocompromised patients.11 • the benefits and risks of antibiotic prophylaxis, and

Progressive narrowing of pulp chambers and root canals an explanation as to why antibiotic prophylaxis is no
(due to excessive dentine formation) in patients receiving longer routinely recommended;
substantial doses of corticosteroids following renal trans-
plantation has been observed.12 There is no need for anti- • the importance of maintaining good oral health;
biotic prophylaxis when undertaking dental treatment in • symptoms that may indicate infective endocarditis
these patients, although some renal transplant units still
advise the need for prophylaxis. In such circumstances, it and when to seek expert advice;
would be advisable to discuss the individual case with the
unit concerned. • the risks of undergoing invasive procedures,

Endodontics and infective including non-medical procedures such as body
endocarditis piercing or tattooing.

Infective endocarditis (IE) is an uncommon but life- Endodontics in patients with
threatening condition with an overall mortality of 20%. prosthetic hip joints
Since 1955 antibiotic prophylaxis has been recommended
for at risk individuals on the basis that endocarditis usually There is no special risk to patients with hip or knee
follows bacteraemia as a result of certain dental proce- prostheses from any form of dental treatment, and cer-
dures and the bacteria responsible are usually sensitive to tainly not from endodontic procedures.19 However, some
antibiotics.13 However, the evidence for the use of anti­ orthopaedic patients are still advised of the need for anti-
biotic prophylaxis relied heavily on extrapolation from biotic prophylaxis and in such cases, it would be advisable
animal models14 and their application to humans has to discuss the individual situation with the surgeon
been questioned. Similarly, the assumption that antibiotic concerned.
prophylaxis is effective for the prevention of IE has not
really been proven.15 Endodontics in patients taking
warfarin or corticosteroids
Recent guidelines by the British Society for Antimicro-
bial Chemotherapy16 and the American Heart Associa- Increasing numbers of patients are taking regular medica-
tion17 have challenged existing dogma by highlighting tion for a variety of conditions. Amongst those of particu-
the prevalence of bacteraemias that arise from everyday lar relevance to the management of dental patients are
activities such as toothbrushing, the lack of association warfarin and corticosteroids. Warfarin is a commonly used
between episodes of IE and prior interventional proce- oral anticoagulant in the management of several medical
dures, and the questionable efficacy of antibiotic prophy- conditions. Its action is monitored by means of the Inter-
laxis regimens. Against this background, the Department national Normalised Ratio (INR); the desired therapeutic
of Health (England) asked the National Institute for range (deep vein thrombosis INR 2.0–3.0, prosthetic heart
Health and Clinical Excellence (NICE), the body respon- valve INR 3.0–4.0) and the duration of treatment is
sible for recommending what treatment and medication dependent on the medical condition. In such cases, the
should be available on the National Health Service, first question is whether the warfarin therapy is to be
to look at conflicting advice in relation to antibiotic discontinued at any time? If it is, then a decision can
prophylaxis against IE. After an independent review of be made as to whether the proposed treatment can be
the available scientific evidence, NICE has recommended deferred until that time. However, if treatment is required,
that for people at risk of developing IE undergoing dental or the warfarin therapy is ongoing, the INR will need to
procedures:18 be reconsidered. Warfarin therapy should not be stopped
or altered prior to dental treatment without the agreement
• antibiotic prophylaxis is not recommended; of the anticoagulant team.
• chlorhexidine mouthwash should not be offered;
Endodontic treatment, with or without local anaesthe-
sia (except inferior alveolar nerve blocks), can safely be
undertaken with an INR of 4.0 or less20 and provided the
INR is stable. Apical surgery, involving raising a mucope-
riosteal flap and bone removal, is best avoided above an

12

General and systemic aspects of endodontics Chapter | 2 |

INR of 2.5, as are inferior alveolar nerve blocks. In all BON in patients taking oral therapy developed after at
cases the INR should be formally checked within 24 hours, least 3 years of therapy with the incidence and severity
prior to the procedure and ideally on the day of increasing linearly thereafter.22 The risk is also increased
treatment.20 Patients presenting with an INR much higher by concomitant corticosteroid therapy.
than their normal value, even if it is less than 4.0, should
have their procedure postponed and should be referred Endodontic treatment is preferable to extraction if a
back to the clinician maintaining their anticoagulant tooth is restorable. Routine endodontic technique should
therapy.20 The use of low-dose aspirin as an anti-platelet be used although manipulation beyond the apex is to be
drug is also unlikely to pose significant problems provided avoided.23 If extractions or bone surgery are necessary, the
appropriate local measures are employed.21 patient should be informed of the risk of BON and alter-
native treatment options considered. In some situations,
Corticosteroids may be administered topically, via an depending on risk, removal of the clinical crown and
inhaler or systemically. Systemic corticosteroids taken endodontic treatment, to allow passive exfoliation of the
above a dose of 7.5 mg (10 mg in some guidelines) daily remaining root may be appropriate. In all cases a conserva-
for over a month, or in high doses (>40 mg per day) for tive surgical technique should be adopted with primary
periods as short as a week may cause adrenocortical sup- closure, if possible.23 In addition, immediately before and
pression. In the case of high doses for short periods after any surgical procedures involving bone, the patient
(‘pulsed’) the effects are not clinically significant after a should be instructed to rinse gently with a chlorhexidine-
month off treatment and deferral of treatment until this containing mouthwash until the wound has healed. The
time would be prudent. In the case of long-term corticos- regimen may be extended depending on the progress of
teroid therapy, prophylaxis is required and is best admin- healing. The use of prophylactic antibiotics after a surgical
istered either orally or intravenously. Two regimes may be procedure should be based on the risk of developing an
employed depending on the preference of the patient and infection and not on the patient’s bisphosphonate therapy.
clinician. The first requires that the patient doubling the There is no evidence that the use of antibiotics is effective
normal daily dose the day before, the day of and the day in preventing BON.23
after treatment. The second is a one-off dose of 100  mg
hydrocortisone administered orally 1 hour prior to treat- USE OF ANTIBIOTICS IN
ment, or intravenously a few minutes before treatment. ENDODONTICS

It should also be noted that some inhaled cortico­ Antibiotics or other antimicrobial drugs are either
steroids, e.g. fluticasone, may cause adrenal suppression. bacteriocidal (kill susceptible bacteria) or bacteriostatic
Similarly, potent topical corticosteroids prescribed by der- (arrest their multiplication), and so allow the natural
matologists, e.g. Eumovate (clobetasone butyrate), applied defence processes to combat infection, and healing to
to large areas, particularly if ulcerated, may also produce progress (Table 2.2). They do not relieve pain or reduce
suppression and require corticosteroid prophylaxis prior swelling and should not be used to treat pulpitis,24
to dental treatment. but reserved to control a spreading cellulitis or a periapical
abscess together with drainage. Overuse should be
Endodontics in patients taking avoided to prevent further increase in resistant strains of
bisphosphonates
Table 2.2  Useful antibacterial drugs
Bisphosphonates are increasingly prescribed to reduce
the morbidity of osteoclast-mediated bone diseases such Treatment of infections
as osteopenia, osteoporosis, fibrous dysplasia, Paget’s
disease, multiple myeloma and metastatic bone cancer. Phenoxymethylpenicillin capsules, 250 mg
The relevance of these drugs to the dental surgeon is their one or two 6-hourly, at least 30 minutes before food,
association with osteonecrosis of the jaws following dental for 4–7 days
intervention. The condition has a predilection for the
molar region and, in particular, in the mandible. Amoxicillin capsules, 250 mg
one or two 8-hourly for 4–7 days
The risk of bisphosphonate-associated osteonecrosis
(BON) is related to the type, dose and duration of Augmentin capsules, 375 mg
bisphosphonate therapy as well as the nature of the one or two 8-hourly for 4–7 days
dental intervention. Intravenous bisphosphonate therapy
(pamidronate, zoledronate) confers a much higher risk of Metronidazole tablets, 200 mg
BON (up to 20%) than oral therapy (alendronate, residro- one or two 8-hourly for 3–5 days
nate and ibandronate) where the risk is 0–0.04%.22 The
risk of BON increases with the duration of therapy, most
cases developing after a mean of around 9 months of
treatment for intravenous bisphosphonates. All cases of

13

Harty’s endodontics in clinical practice

microorganisms25 and adherence to clinical guidelines is Table 2.3  Useful analgesics
recommended.26
Mild to moderate pain
Ideally, the choice of an antibiotic should be based on
the results of identification and sensitivity testing of the Aspirin tablets, 300 mg (or aspirin tablets dispersible,
microorganisms responsible for the infection. This is 300 mg)
seldom feasible in clinical practice and requires culture one to three every 4–6 hours as necessary, maximum
techniques in a laboratory setting, as simple Gram staining 4 g/day
and microscopy is of little help. However, most of the
bacteria associated from dentoalveolar infection are still Paracetamol tablets, 500 mg
sensitive to penicillins and hence, if not allergic, phe- one to two every 6 hours as necessary, maximum
noxymethylpenicillin 250 mg or 500 mg, four times a day 4 g/day
for 5 days, depending on the severity of the infection, is
appropriate.26 Amoxicillin 250  mg, three times a day for Ibuprofen tablets, 200 mg
5 days may be preferred because of its efficient absorption. one to two every 4–6 hours, as necessary, preferably
Metronidazole 200 mg or 400 mg, three times a day for 3 after food, maximum 2.4 g/day
to 5 days will assist in the elimination of anaerobes and
may be used alone or in combination with penicillin. The Moderate to severe pain
newer penicillinase-resistant antibiotic Augmentin (amox-
icillin 250  mg and clavulanic acid 125  mg) may be pre- Dihydrocodeine tablets, 30 mg
ferred for ease of use and patient compliance. A potential one every 4–6 hours, as necessary after food, maximum
unwanted side-effect of the use of broad-spectrum antibi- 1.8 g/day
otics is interference with absorption of the oestrogen com-
ponent of combined oral contraceptives, with consequent Severe pain
loss of effect. Women taking such preparations concur-
rently should be advised not to rely on this method of Pethidine tablets, 50 mg
contraception alone for one month after the end of the one to two every 4 hours, maximum 6 g/day
antibiotic course. In addition, antibiotics are known to
potentiate the action of warfarin, which may upset the Conscious sedation using either an inhaled mixture of
therapeutic control.27 Erythromycin and other macrolide nitrous oxide and oxygen, or intravenous administration
antibiotics interact with warfarin unpredictably and only of midazolam, is a safe and effective way of overcoming
in certain individuals. Metronidazole also interacts with anxiety. Such techniques are only rarely required for root
warfarin and should be avoided if possible. If necessary, canal treatment, however, sedation may more often be
the patient should, therefore, be advised to contact their required for apical surgery.
anticoagulant centre for appropriate follow-up.
Analgesics
CONTROL OF PAIN AND ANXIETY
Analgesics may be used to treat existing pain, or to reduce
Pain and anxiety control are central to successful endo- postoperative pain (Table 2.3). Analgesics administered
dontic treatment. The drugs available for local analgesia preoperatively, as a pre-emptive measure, are useful in
and for sedation are both safe and effective, but, as with reducing postoperative pain. Aspirin and paracetamol
any potent therapeutic agent, need to be employed with (acetaminophen) remain the most effective and widely
skill and discretion, particularly in patients who are taking used remedies for local pain of mild to moderate severity.
other medication regularly. A whole spectrum of tech- Aspirin is contraindicated in patients with peptic ulcera-
niques of control of pain and anxiety are applicable in tion, bleeding diatheses, or who are taking systemic corti-
endodontics as in other dental treatment. These range costeroids. It is also not advised in children because of the
from simple persuasion and a comforting and sympathetic risk of causing Reye’s syndrome. When paracetamol is
manner, through to sedation. Local anaesthetic techniques used, it is essential to warn patients not to exceed the daily
are well established, and 2–4 ml of lidocaine (lignocaine) maximum dose of 4 g, because of the risk of severe and
2% with 1 : 80,000 adrenaline (epinephrine) is a safe and sometimes fatal liver damage. Other non-steroidal anti-
effective preparation for all patients. An aspirating syringe inflammatory drugs (NSAIDs) such as ibuprofen may be
system should be used to help avoid inadvertent intravas- used if preferred and may be used in combination with
cular injection. Only in very rare cases where true allergy paracetamol if required. For patients who are taking war-
to lidocaine is proven, need an alternative solution, e.g. farin, analgesics such as ibuprofen, aspirin and diclofenac
prilocaine with felypressin, be used. should not be used.27

Dihydrocodeine tartrate is used to relieve more severe
pain, but frequently causes unpleasant side-effects, includ-
ing dizziness and nausea, and may prove ineffective. On

14

General and systemic aspects of endodontics Chapter | 2 |

the rare occasions that severe pain persists, then pethidine and analgesics as well as information on potential drug
50 mg, one or two tablets 4-hourly, can be given and the interactions, prescribing during pregnancy and medical
patient’s condition reviewed the next day. Local treatment, emergencies in dental practice are particularly useful. A
e.g. drainage and irrigation of a root canal, making a tooth dentist’s guide to using this formulary and advice on
free of occlusal contact, replacement of a failed temporary rational prescribing was recently published as a two-part
filling following root canal cleaning, or irrigation of a series of articles.28,29 Further information on medical
surgical wound, are far more effective ways of dealing with aspects of dentistry, is available in ‘Medical Problems in
pain than the indiscriminate use of analgesics. Dentistry’.30

BRITISH NATIONAL FORMULARY LEARNING OUTCOMES

This formulary,19 which includes the Dental Practitioner’s After reading this chapter, the reader should:
Formulary, published jointly by the British Medical
Association and the Royal Pharmaceutical Society of Great • be aware of the differential diagnosis of orofacial pain
Britain is a succinct and authoritative guide to prescribing • understand the relevance of concurrent, systemic
for the dentist and is regularly updated. It is an invaluable
source of advice and information and should be available disease as well as medication to treatment planning
in every dental surgery. The sections on antibiotics and management of endodontic patients

• be familiar with the use of analgesics and antibiotics

in endodontic cases.

REFERENCES

1. Hampton JR, Harrison MJ, Mitchell 7. Ahovuo-Saloranta A, Borisenko 13. Durack DT. Prevention of infective
JR, et al. Relative contributions of OV, Kovanen N, et al. Antibiotics endocarditis. New England Journal
history-taking, physical for acute maxillary sinusitis. of Medicine 1995;332:38–44.
examination and laboratory Cochrane Database Systemic
investigations to diagnosis and Reviews 2008;Art. No. 14. Pallasch TJ. Antibiotic prophylaxis:
management of medical (2):CD000243. problems in paradise. Dental
outpatients. British Medical Journal Clinics of North America 2003;47:
1975;2:486–489. 8. Beck-Mannagetta J, Necek D. 665–679.
Radiologic findings in aspergillosis
2. Roshan M, Rao AP. A study on of the maxillary sinus. Oral 15. Prendergast BD. The changing face
relative contributions of the Surgery, Oral Medicine, Oral of infective endocarditis. Heart
history, physical examination and Pathology 1986;62:345–349. 2006;92:879–885.
investigations in making medical
diagnosis. Journal of the 9. Giardino L, Pontieri F, Savoldi E, 16. Gould FK, Elliott TSJ, Foweraker J
Association of Physicians of India Tallarigo F. Aspergillus mycetoma et al. Guidelines for the prevention
2000;48:771–775. of the maxillary sinus secondary of endocarditis: report of the
to overfilling of a root canal. Working Party of the British
3. Department of Health. Health Journal of Endodontics 2006;32: Society for Antimicrobial
Technical Memorandum 01-05: 692–694. Chemotherapy. The Journal of
Decontamination in primary care Antimicrobial Chemotherapy
dental practices. London: 10. Khongkhunthian P, Reichart PA. 2006;57:1035–1042.
Department of Health; 2008. Aspergillosis of the maxillary sinus
as a complication of overfilling 17. Wilson W, Taubert K, Gewitz M
4. Zakrzewska J, Harrison SD. Pain root canal material into the sinus: et al. Prevention of infective
Research and Clinical Management: report of two cases. Journal of endocarditis. Guidelines from the
Volume 14, Assessment and Endodontics 2001;27:476–478. American Heart Association: A
management of orofacial pain. Guideline from the American Heart
Amsterdam: Elsevier; 2002. 11. DePaola LG, Peterson DE, Association Rheumatic Fever,
Overholser Jr CD, et al. Dental care Endocarditis and Kawasaki Disease
5. Solomon PE, Prkahin KM, Farewell for patients receiving Committee, Council on
V. Enhancing sensitivity to facial chemotherapy. Journal of the Cardiovascular Disease in the
expression of pain. Pain 1997;71: American Dental Association Young and the Council on Clinical
279–284. 1986;112:198–203. Cardiology, Council on
Cardiovascular Surgery and
6. Whooley MA, Avins AL, Miranda J, 12. Näsström K, Forsberg B, Petersson Anaesthesia and the Quality of
Browner WS. Case–finding A, Westesson PL. Narrowing of the Care and Outcomes Research
instruments for depression. Two dental pulp chamber in patients Interdisciplinary Working
questions are as good as many. with renal diseases. Oral Surgery, Group. Circulation 2007;116:1736–
Journal of General Internal Oral Medicine, Oral Pathology 1754.
Medicine 1997;12:439–445. 1985;59:242–246.

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Harty’s endodontics in clinical practice

18. Prophylaxis against infective 22. Marx RE, Cillo JE, Ulloa JJ. Oral <http://www.who.int/
endocarditis: NICE guidelines. bisphosphonate-induced drugresistance/Antimicrobial_
National Institute for Health and osteonecrosis: Risk factors, resistance_recommendations_of_
Clinical Excellence. Online. predilection of risk using serum expert_polic.pdf>; 2001.
Available: <http://www.nice. CTX testing, prevention and
org.uk/nicemedia/pdf/ treatment. Journal of Oral and 26. Adult antimicrobial prescribing in
CG64NICEguidance.pdf>; 2008. Maxillofacial Surgery 2007;65: primary dental care for general
2397–2410. dental practitioners. London, UK:
19. British National Formulary. Faculty of General Dental Practice
London: British Medical 23. Edwards BJ, Hellstein JW, Jacobsen UK, Royal College of Surgeons of
Association & Royal PL et al. Updated recommendations England; 2006.
Pharmaceutical Society of Great for managing the care of patients
Britain; September 2008. receiving oral bisphosphonate 27. Managing patients who are taking
therapy: An advisory statement warfarin and undergoing dental
20. Surgical management of the from the American Dental treatment. National Patient Safety
primary care dental patient on Association Council on Scientific Agency, London, UK. Online.
warfarin. North West Medicines Affairs. Journal of the American Available: <http://www.npsa.nhs.
Information Centre, Liverpool, UK. Dental Association 2008;139: uk/nrls/alerts-and-directives/alerts/
Online. Available: <http://www. 1674–1677. anticoagulant/>; 2009.
nelm.nhs.uk/en/NeLM-Area/
Evidence/Medicines-Q--A/ 24. Nagle D, Reader A, Beck M, Weaver 28. Wray D, Wagle SMS. A dentist’s
Surgical-management-of-the- J. Effect of systemic penicillin on guide to using the BNF: part I.
primary-care-dental-patient-on-warf pain in untreated irreversible British Dental Journal 2008;204:
arin/?query=warfarin+++surgical+m pulpitis. Oral Surgery, Oral 437–439.
anagement&rank=5>; 2007. Medicine, Oral Pathology, Oral
Radiology & Endodontics 29. Wray D, Wagle SMS. A dentist’s
21. Ardekian L, Gaspar R, Peled M, 2000;90:636–640. guide to using the BNF: part II.
et al. Does low-dose aspirin British Dental Journal 2008;204:
therapy complicate oral surgical 25. World Health Organisation. 487–491.
procedures? Journal of the Antibiotic resistance: synthesis of
American Dental Association recommendations by expert 30. Scully C, Cawson RA. Medical
2000;131:331–335. policy groups. Online. Available: problems in dentistry. 5th ed.
Amsterdam: Churchill Livingstone/
Elsevier; 2005.

16

3Chapter  

Diagnosis

S. Patel, B.S. Chong

CHAPTER CONTENTS Pulp extirpation 29

Summary Root canal treatment 29
Introduction 17 Root canal retreatment 30
History 17 Learning outcomes 30
18 References 31
Presenting complaint 18
History of presenting complaint
Dental history 18 SUMMARY
Medical history
Examination 18
Extraoral
Intraoral 18 Diagnosis is the first step in the care and management of
Investigations
Pulp sensitivity tests 18 any patient. A systematic and organized approach is
Bite/cusp loading tests 18 important in order to avoid misdiagnosis. Special test and
Selective local anaesthesia additional investigations may be necessary to help confirm
Blood flow assessment 19 a provisional diagnosis. Until and unless a clear diagnosis
Radiographs
Differential diagnosis 21 is possible, invasive and irreversible treatment may have
Pulpal conditions
Periapical conditions 21 to be delayed. However, once a confirmed diagnosis has
Restorability
Treatment options 24 emerged, in conjunction with the patient, the various
Watch and review treatment options can then be considered. Depending on
Save tooth 24 patient’s preference, a treatment plan is formulated and
Lose tooth
Specific endodontic treatment options 24 then carried out to resolve the patient’s complaint. Referral
Pulp monitoring 25 to a specialist may, sometimes, be necessary to help estab-
Pulp preservation
26 lish a diagnosis or if complex endodontic treatment is
© 2009 Elsevier Ltd, Inc, BV 26 required.
DOI: 10.1016/B978-0-7020-3156-4.00006-1
28 INTRODUCTION
28

29 Diagnosis is the process of identifying a disease or an
29 abnormal condition by collecting and evaluating the
29 patient’s presenting signs and symptoms, and the results

29 of further investigations. A clear diagnosis can only
be reached when information is collected systematically
29 and interpreted accurately. Without a correct diagnosis,

29 the clinician will not be able to manage and provide
29 appropriate treatment to resolve the patient’s complaint.

17

Harty’s endodontics in clinical practice

If a diagnosis cannot be reached, irreversible treatment whilst others may see their dentist on a more regular basis.
may have to be delayed. The maxim ‘first do no harm’ is It is also important to determine if the patient has recently
a reminder it may be better to do nothing than something had dental treatment in the region of interest because
that risks causing more harm than good. If a diagnosis unless it is purely coincidental, it may be related to the
cannot be established, a referral to an appropriate special- presenting complaint. Other relevant snippets of informa-
ist should be considered. tion gleaned from the dental history may provide clues to
possible factors contributory to the patient’s complaint.
HISTORY For example, a history of dental trauma may explain
symptoms of irreversible pulpitis associated with an
Taking an accurate history from the patient is the first step otherwise clinically unremarkable tooth.
in diagnosis. The clinician can then decide the direction
the diagnostic process should take, for example, the Medical history
additional investigations or special tests required. Subject
to confirmation, a tentative diagnosis may be possible at An up-to-date medical history is required. Unless already
this stage. documented, normally the patient is requested to com-
plete a medical history form beforehand, which the clini-
As well as helping to establish the reasons for the cian will then go through with the patient. It is imperative
patient’s attendance, the history may also reveal the to ascertain if there are any medical conditions or medica-
patient’s attitude and motivation towards dental treatment. tions that the patient may be taking, which may alter their
The clinician may be alerted to potential patient manage- dental management. In addition, patients should be asked
ment problems, for example, if the patient mentioned pre- if they are allergic to latex (rubber dam and rubber gloves),
vious difficulties in achieving adequate anaesthesia or an household bleach (sodium hypochlorite) and iodine;
intolerance to having dental instruments in the mouth. materials they will be in contact with during endodontic
treatment. The subject of the patient’s general health and
Presenting complaint potential impact on endodontic treatment is covered in
Chapter 2.
Patients should be questioned sympathetically and asked
to describe their complaint in their own words; this should EXAMINATION
then be documented. Their cooperation and ability to
describe their complaint accurately will greatly aid diag- Extraoral
nosis. The questions asked should be open ended and not
leading, for example, ‘What brings you to see me today?’ The patient’s general well-being and demeanour will be
With endodontic problems, pain and/or swelling are noticeable during consultation. Signs of facial asymmetry,
usually the predominant complaints. Typically with pain, swelling and/or trismus may also be apparent (Fig. 3.1).
a series of follow-up questions is necessary to help estab- However, less obvious signs may only be revealed follow-
lish the character, duration, severity and other features of
the pain or discomfort (see Chapter 2, Table 2.1).

History of presenting complaint

Often, the presenting complaint is not new but previous
symptoms may have been mild or they may have tempo-
rarily abated. The patient may be unaware that treatment
is required or may have even chosen to ignore the problem,
especially if no longer causing symptoms. However, a his-
torical perspective and the chronology of the presenting
complaint are still necessary as it will provide relevant
information for arriving at a diagnosis.

Dental history Figure 3.1  An extraoral swelling and associated facial
asymmetry that will be obvious upon meeting the patient.
It is helpful to gain an insight into the patient’s past and
present dental history including pattern of attendance.
Some patients may only attend when they are in pain,

18

Diagnosis Chapter | 3 |

AB

Figure 3.2  (A) Clinical view of the buccal sinus tract associated with a maxillary central incisor. (B) Periapical radiograph of
tooth showing an overextended and sub-optimal root canal filling.

ing closer examination. The lymph glands, temporoman-
dibular joint and muscles of mastication are assessed. The
degree of mouth opening possible should also be noted
because if limited, access for endodontic treatment may
be hindered.

Intraoral Figure 3.3  The state of the dentition will provide an overall
clinical view of the patient’s past dental history.
Soft tissues

The general state of the soft tissues should be assessed.
Scalloping of the lateral borders of the tongue and/or
frictional keratosis of the buccal mucosa may indicate a
parafunctional habit. The area of interest requires
more detailed assessment (see later). Signs, such as a swell-
ing or the presence of a sinus tract should be noted
(Fig. 3.2).

Hard tissues If evident, the severity and distribution of tooth surface
loss should be recorded. Localized wear facets and fracture
The dentition, including the state and quality of existing lines may indicate an occlusal component to the patient’s
restorations is assessed; this will provide an overall clinical symptoms (Fig. 3.4). If a cracked tooth is suspected it may
view of the patient’s dental history (Fig. 3.3). Combined be necessary to assess individual cusps by occlusal loading
with the oral hygiene status, general periodontal probing (see later). Transillumination, using a light source placed
profile and caries experience, these are relevant when on the side of the tooth may help reveal otherwise hard
devising a treatment plan.

19

Harty’s endodontics in clinical practice

Figure 3.6  A large carious cavity in a maxillary right first
molar. The clinical picture suggested possible pulpal
involvement and the need for endodontic treatment.

Figure 3.4  Excessive generalised tooth surface loss in this greatly aid visualisation allowing a detailed examination
mandibular left second molar has resulted in pulpal (see Chapter 6).
symptoms.

Figure 3.5  Transillumination using a fibreoptic light. Specific tooth/teeth

to detect fracture lines (Fig. 3.5). Special dyes, such as The area of interest and specific tooth/teeth are assessed
methylene blue (Vista-Blue, Vista Dental Products, Racine, in more detail. The occlusion and the strategic nature
WI, USA) may also be used to highlight a fracture line of the tooth are considered, for example, if a tooth is
once its approximate position is known. In general, unopposed or non-functional. The colour of the tooth,
the use of magnification and enhanced illumination should be compared with adjacent teeth; any darkening
of the clinical crown may be related to a history of trauma.1
The possible causes of pulpal or periapical diseases are
noted, for example, the presence of primary or secondary
caries (Fig. 3.6), fracture lines (Fig. 3.7) and extensive
dentine exposure due to tooth surface loss. The restorabil-
ity of the tooth must be assessed. The extent of any
caries, the size of existing restorations and the amount of
original tooth substance left will provide an indication
about restorability; there is further discussion on this
subject later.

Palpation

The buccal/labial and palatal/lingual mucosa are palpated.
Light finger pressure is applied in a rolling motion on the
soft tissues using, normally, an index finger (Fig. 3.8).
Signs of tenderness usually indicate inflammation of the
underlying tissue.

20

Diagnosis Chapter | 3 |

Figure 3.9  Tooth percussion performed using a forefinger.

Figure 3.7  A mandibular right first molar with stained crack
lines and an old amalgam restoration that is leaking, with
evidence of secondary caries underneath.

Figure 3.10  The periodontal probe must be walked around
the tooth to ensure that any isolated narrow periodontal
defects are not missed.

Figure 3.8  Light finger pressure is applied in a rolling causes of increased mobility include periodontal disease,
motion to palpate the soft tissues. root fracture and acute apical periodontitis.

Percussion Periodontal probing

Teeth are percussed in an axial and buccal direction using Probing depths should be assessed by ‘walking’ the peri-
a forefinger (Fig. 3.9) or the end of a mirror handle. Ten- odontal probe around the entire circumference of the
derness to gentle percussion indicates inflammation of the tooth (Fig. 3.10). The probing profile for root fractures
periodontal ligament surrounding the tooth; this may be and iatrogenic perforations is, characteristically, an iso-
of pulpal or periodontal in origin. lated localised loss of attachment. Whereas loss of attach-
ment due to periodontal disease is usually more generalised
Mobility and not associated with a singular defect. Furcation
involvement may indicate advanced periodontal disease
With fingers or combined with a mirror handle, any (Fig. 3.11) or an iatrogenic root perforation.
abnormal tooth mobility should be noted. Common
INVESTIGATIONS

Pulp sensitivity tests

Currently available sensitivity tests assess the neural
response, and not the vascular supply of the pulp, the

21

Harty’s endodontics in clinical practice

Figure 3.11  Advanced periodontal disease. Figure 3.12  Cold thermal test; a refrigerant is sprayed on a
small cotton pellet and applied to the tooth.
assumption with these tests is that the neural status reflects
the blood supply status of the tooth.2,3 With any sensitivity
test, an explanation should be given to the patient about
the rationale for the test. Otherwise, particularly with an
anxious patient, false positive responses will result. An
adjacent tooth, considered healthy, should be tested first;
this will act as the control and allow the patient to experi-
ence the likely response.

Thermal tests Figure 3.13  A tooth is isolated with rubber dam and bathed
with cold water; this is repeated for each tooth in the
Cold test quadrant to try to reproduce the patient’s symptoms.

Cold thermal tests work by causing contraction of the ticularly useful test when a patient is complaining of a
dentinal fluid within the dentine tubules; this rapid poorly localized pain provoked by cold (Fig. 3.13). The
outward flow of movement results in ‘hydrodynamic colder the applied stimulus the more reliable the test as
forces’ acting on the Aδ nerve fibres.4,5 There is a sharp there is a greater temperature reduction within the den-
sensation, lasting for up to a few seconds after the cold tine-pulp complex.7,8 This is important in posterior teeth
stimulus has been removed from the tooth.6 Several types as the thickness of both dentine and enamel is greater than
of cold tests are available; the main difference between that in anterior teeth. A negative response may be because
them is the operating temperature. the applied stimulus is not cold enough. A prolonged and
lingering response usually indicates irreversible pulpitis.
Ice sticks (0°C) are made by filling discarded, sterilized Cold tests appear to be more effective in assessing nerve
local anaesthetic needle covers with water and placing status than heat tests.9,10
them in the freezer. They have the advantage of being
inexpensive and easy to prepare. However, false negative Heat test
responses can occur as a result of water droplets contacting
adjacent teeth and gingivae, as the ice melts. Commer- Heat may be applied to a tooth using a heat-softened
cially available refrigerant spray containing tetrafluoro­ gutta-percha stick. A thin layer of petroleum jelly should
ethane (−50°C) is convenient and easy to use. It is sprayed first be applied to the test surface to prevent the gutta-
onto a small cotton pellet and then applied to the tooth
(Fig. 3.12). Carbon dioxide snow (−78.5°C) is also very
effective. Carbon dioxide is expressed into a plunger
mechanism from a pressurised gas cylinder, and then com-
pressed into a stick of carbon dioxide snow. This is then
placed on the tooth to be tested using a special applicator.
Being the coldest, carbon dioxide snow is particularly
useful for assessing teeth restored with full coverage
restorations.

Teeth may also be isolated individually with rubber
dam, and then bathed with cold water. This test is a par-

22

Diagnosis Chapter | 3 |

percha sticking to the tooth. Another way of applying heat tooth to be assessed is isolated with cotton wool and
to a tooth is by running a rubber prophylaxis cup dry, in dried. Depending on the EPT, the patient is asked to hold
a slow handpiece, to generate frictional heat on the crown the handle of the probe, or a lip hook is placed, to form
of the tooth11 but this method is seldom used; a false posi- one loop of the circuit. The tip of the probe is usually
tive response may be obtained because of the vibrations, coated with a conducting medium (e.g. toothpaste) to
and particularly if the patient is anxious. improve electrical transmission to the tooth. When the
probe is placed onto the tooth (Fig. 3.14), the circuit is
Individual teeth may also be isolated with rubber dam complete. If desired, strips of rubber dam or cellulose
and warm water applied. Again, this test is particularly strips may be used interproximally to reduce the likeli-
useful when the patient complained of poorly localized hood of electrical conduction to adjacent teeth.3
heat sensitivity. Prolonged application of heat to a tooth
can result in stimulation of C-fibres, resulting in lingering As the test proceeds, the strength of the electrical stimu-
pain.12 For testing purposes and for this reason, heat lus will increase and when sensation is elicited, the patient
should only be applied to a tooth for a maximum of is advised to either let go of the handle of the probe which
5 seconds.3 breaks the circuit, or signal to the clinician so the probe
may be removed. The reading on the EPT, either numerical
Electric pulp test or arbitrary is then recorded. If numerical, the digital
readout is relative rather than an accurate quantitative
Electric pulp testers (EPTs) are battery operated units (Fig. measurement of the health status of the pulp. Apart from
3.14). They produce negative pulses of electricity, with a a total lack of response suggesting a lack of vitality, EPT
maximum current of a few milliamperes. The current can readings are merely an indication, a comparative measure-
be adjusted; it is either controlled by the operator or it ment as healthy teeth will respond over a range of values.
increases automatically when the unit is activated.13 The The threshold for obtaining a positive response depends
on the position of the probe on the tooth and the thick-
A ness of the enamel and dentine. The probe of the EPT
should be placed adjacent to the pulp horn as this is where
B there is the highest density of nerves. In the case of ante-
Figure 3.14  (A) A typical electric pulp tester. (B) The probe rior and posterior teeth this is at the incisal and mid-third
is placed on the incisal third of the crown of the tooth; region of the tooth respectively14,15,16 (Fig. 3.14). The
toothpaste is used to help improve conduction. thicker the enamel and dentine, the higher the excitation
threshold; for this reason, the probe should be placed
where the enamel is thinnest.17 This explains why for a
given test, the excitation threshold increase from incisor
to premolar to molar teeth as the thickness of the overly-
ing enamel and dentine increases.12,18

A tingling or warm sensation indicates a healthy ‘posi-
tive’ response. This is a result of Aδ nerve fibres being
stimulated, resulting in an ionic shift in the dentinal fluid
causing a localized depolarisation and the generation of
an action potential from the healthy nerve.19 A lingering,
dull ache following the removal of the EPT probe is a
result of stimulation of the C-fibres, which is indicative of
irreversible pulpal inflammation. No response from elec-
tric pulp testing indicates that the tooth is non-vital, i.e.
the pulp is necrotic. Saliva conduction through the peri-
odontal ligament may result in a false positive reading; a
negative response may also be due to the failure to com-
plete the electrical circuit. A review on electric pulp testing
was published recently;20 included is the important
reminder that electric pulp tests can be unreliable, espe-
cially in the case of immature and concussed teeth.

A study to evaluate the ability of thermal and electrical
tests to register pulp vitality2 reported that the probability
of a non-sensitive reaction representing a necrotic pulp
was 89% with the cold test, 88% with the electrical test
and 48% with the heat test. It also indicated that the prob-
ability of a sensitive reaction representing a vital pulp was

23

Harty’s endodontics in clinical practice

90% with the cold test, 84% with the electrical test and
83% with the heat test. The results of this study would
suggest that, in descending order of accuracy: the cold test
followed by the electrical test and then the heat test.

Test cavity preparation A

Historically, test cavity preparation has been suggested as B
a technique to assess the pulp status when all other tests Figure 3.15  Bite/cusp loading test. (A) The patient is asked
are inconclusive. Local anaesthetic is not administered to bite on a cotton roll to try and reproduce symptoms of
and a small bur is used with copious irrigation to prepare localized tenderness to chewing. (B) A wedging device may
a small cavity down the centre of the tooth into dentine.21 be used to apply more specific pressure to individual cusps.
If the patient feels sensitivity, this may indicate that the
tooth is vital; alternatively, it may indicate that the tooth
is unhealthy as Aδ fibres may still be viable in necrotic
pulp tissue. No response indicates a lack of pulpal vitality.
However, if the pulp tissue has receded away from the
centre of the tooth and an excessive amount of tertiary
dentine has been deposited within the root canal system,
the dentinal tubules being transected may not communi-
cate with the vital odontoblastic processes, hence a nega-
tive response.

The patient’s response to all sensitivity testing is subjec-
tive.22,23 There is a poor correlation between signs and
symptoms, and pulpal and periapical histopathol-
ogy.10,24,25,26 When the results of five studies were analysed
in an attempt to correlate clinical findings with the his-
topathological status of teeth, it was concluded that the
results of these tests were more likely to be correct when
teeth are healthy than diseased.27 Sensitivity tests by itself
are of limited value; they should be used when indicated
as an adjunct, as part of the diagnostic process.24,28

Bite/cusp loading tests testing is equivocal, then selective local anaesthesia may
be helpful. Using the intraligamental local anaesthetic
Tenderness to bite is indicative of inflammation of the injection technique, the clinician should first selectively
periodontium and a common presenting symptom. The anaesthetize teeth in the maxillary quadrant starting from
more specific cusp loading bite test using some form of the distal sulcus of the most posterior tooth. The local
wedging device is indicated for patients with a suspected anaesthetic is then administered more forward, one tooth
cusp, tooth or root fracture presenting with poorly local- at a time, until the pain disappears. If, after an appropriate
ized pain on biting.29 The patient is instructed to bite interval, the pain persists, selective local anaesthesia
firmly on a cotton roll (Fig. 3.15A) or a commercially should, similarly, be performed in the mandibular quad-
available ‘Tooth Slooth’ (Professional Results, Inc., Laguna rant. Selective local anaesthesia is usually better at pin-
Niguel, CA, USA) (Fig. 3.15B). The biting pressure results pointing the arch or quadrant rather than a specific tooth.
in the temporary separation of the fractured segments,
thus reproducing the patient’s symptoms. Neighbouring Blood flow assessment
teeth are used as controls.
Various ‘physiometric’ tests have been investigated to
Selective local anaesthesia evaluate the actual blood supply within the tooth. They
include Laser Doppler Flowmetry (LDF), pulse oxime-
If symptoms, particularly pain, are poorly localized or try30,31 and the measurement of tooth temperature using
referred, it will be difficult to identify the source. Often, thermocouples, thermistors, infrared thermography and
patients may be able to indicate that the pain is from the cholesteric liquid crystals;32 most of these methods are
left or right side of their mouth but they may be unsure if experimental.
it is from the mandible or maxilla. If pulp sensitivity

24

Diagnosis Chapter | 3 |

A Radiographs

B Radiographs are an essential component of the diagnostic
process.40 Images from conventional radiography are cap-
Figure 3.16  (A) A bitewing and (B) a periapical radiograph tured on X-ray films or digital sensors. With the latter, the
of the maxillary left quadrant combined to provide sensors are either charged-coupled devices (CCDs) or
information about the quality of existing restorations, extent storage phosphor plates (SPPs). CCD sensors are relatively
of caries, crestal bone levels, pulpal calcifications, root bulky and are available as wired or wireless versions; cap-
morphology and apical health. tured images allow immediate viewing. SPP sensors are
almost equivalent in thickness to conventional X-ray films
LDF, which is a non-invasive technique, appears to and there is no wire connection but irradiated sensors
be the most promising.3,33 A probe which emits a low have to be scanned in a processing unit before images can
energy laser beam is placed against the surface of the be viewed.
tooth. This laser beam travels along the enamel prisms
and dentinal tubules to reach the pulp tissue. On reaching Periapical radiographs may be supplemented with
the pulp tissue, some of the light from the laser beam bitewing radiographs; this view may reveal additional
is absorbed and scattered by red blood cells within the information regarding the quality of any restoration
capillary plexus resulting in a Doppler shift in the fre- present, extent of caries in relation to the pulp, calcifica-
quency of the light reflected back to the probe.34,35 The tions in the pulp chamber and crestal bone levels41 (Fig.
LDF amplifies this reflected light and detects its pulsatility 3.16). Radiographs should be taken using the paralleling
and signal strength. Fourier analysis, a mathematical tech- technique, aided by a beam-aiming device, rather than the
nique, can be used to improve the diagnostic accuracy bisecting angle technique to reduce geometric distortions
of LDF.33 As well as assessing the blood supply of the thus resulting in more accurate images of the apical
tooth, the other major advantages of LDF include more anatomy.42 In addition, the use of a beam-aiming device
objective and reliable results compared with sensitivity allows similar positioning to be reproduced when radio-
tests.32,36 LDF is particularly helpful when the results of graphs are taken at a later date43,44 for review or compara-
other investigations are inconclusive;37 it has also been tive purposes. All radiographs condense the complex
used to detect the pulpal status of traumatized teeth.38,39 three-dimensional anatomy of the tooth and its surround-
Unfortunately, LDF does have its disadvantages, these ing alveolar anatomy into a two-dimensional image. The
include being more time-consuming to perform, tech- parallax technique may be used to detect, for example,
nique sensitive and it cannot be used on extensively additional root canals and improve perception of the
restored or decayed teeth.3 spatial relationship of the root apices to their relevant
surrounding structures (Fig. 3.17).

Cone Beam Computed Tomography (CBCT) is a rela-
tively new imaging technique that has been exclusively
designed for scanning the maxillofacial skeleton.45,46 CBCT
overcomes some of the deficiencies of conventional radio­
graphy.47,48 A series of exposures is taken in a single rota-
tion of a cone shaped X-ray source and the reciprocal
detector around the patient’s head.49 The patient radiation
dose is of the same order of magnitude as conventional
radiography.50,51,52 Reconstruction algorithms convert
these two-dimensional images into a three-dimensional
volume of data and using sophisticated software, proc-
essed into a format which closely resembles that produced
by conventional CT scanners. Selecting and moving the
cursor on one image automatically alters the reconstructed
slices in three orthogonal planes: axial, sagittal and
coronal, thus allowing images to be scrolled through in
real time.53,54,55,56 CBCT produces undistorted and accurate
images of the area under investigation. Studies have con-
cluded that CBCT detects endodontic lesions before they
become visible on conventional radiographs57,58,59,60,61
(Fig. 3.18). This should help improve diagnosis, and may
also result in a more objective assessment of healing of
root treated teeth.54 The compact size of the CBCT scanner
and ease of use has resulted in a relatively rapid uptake in

25

Harty’s endodontics in clinical practice

AB

Figure 3.17  Additional radiographs may be helpful. The first periapical radiograph (A) reveals an inadequately root treated
maxillary right first molar and distal caries in the adjacent second molar; the second, parallax radiograph (B) reveals more
details.

dentistry.54,62 However, the cost of the equipment is not Reversible pulpitis
inconsiderable and limitations include scatter caused by
metallic restorations; the resolution (2–3 lines/mm) is There is mild or transient pulpal inflammation. This may
also inferior to conventional radiography (15–20 lines/ result in the tooth causing sharp pain lasting for up to
mm). At present, CBCT is not yet universally available in 5–10 seconds, which does not linger, after the applied
dental practices. stimulus has been removed. Common causes of reversible
pulpitis include caries and coronal leakage. Radiological
DIFFERENTIAL DIAGNOSIS examination may confirm the presence of caries or a
defective restoration; the periapical tissues will appear
Differential diagnosis is the process of distinguishing normal. Removal of the causal factor/s will, usually, result
between diseases or conditions of similar characteristics in alleviation of pulpal inflammation and the patient’s
by comparing their presenting signs and symptoms. The symptoms.
differential diagnosis of dental pain in general is covered
in Chapter 2; pulpal and periapical conditions are covered Irreversible pulpitis
in this chapter.
The pulp has suffered a more severe insult and is irrevers-
There is no universally agreed diagnostic terminology, ibly inflamed; therefore, the tooth cannot be treated con-
classification scheme or system for pulpal and periapical servatively. Symptoms of irreversible pulpitis may range
diseases. The terms symptomatic/asymptomatic have been from a throbbing pain, initiated by hot or cold stimuli and
suggested to replace acute/chronic; the changes to reflect lasting minutes to hours, to spontaneous intermittent
the nature of the patient’s presenting complaint instead of bouts of aching pain lasting for hours. Symptoms may be
the histological description. The terms apical, periapical exacerbated when the patient lies down or bends over; this
and periradicular are often used interchangeably. The is due to increased intra-pulpal pressure. As mentioned
choice of terminology is a matter of personal preference earlier, the results of clinical examination do not, neces-
and invariably some latitude is necessary. In this chapter, sarily, correlate with the true histopathological status of
the more conservative terms have been retained. the pulp.10,24,25,63 This is especially true with irreversible
pulpitis, which may progress relatively symptom-free to
Pulpal conditions pulp necrosis and subsequent apical periodontitis.64

Normal pulp Clinical examination may reveal caries or a defective
restoration; this may be confirmed by radiological exami-
A tooth with a normal pulp will be symptom-free. The nation but the periapical tissues may appear normal. An
results of clinical examination will be unremarkable, and attempt to reproduce the patient’s symptoms is prudent,
the tooth will respond normally to sensitivity testing. to confirm the diagnosis. With the application of thermal
stimulus there is usually an initial sharp shooting Aδ fibre
type pain lasting for a few seconds, then after a few seconds

26

Diagnosis Chapter | 3 |

A
B

CD

Figure 3.18  (A) A periapical radiograph of the maxillary left first molar showing, apparently, normal periapical health.
(B) Axial, (C) sagittal and (D) coronal reconstructed views from Cone Beam Computed Tomography showing the presence
of a periapical radiolucency associated with the distobuccal and palatal roots (yellow arrow) and the presence of only one
mesiobuccal canal (red arrow).

of quiescence, a dull throbbing C-fibre ache develops If the necrotic tissue has not become infected, then the
which may take minutes to hours to subside even after the periapical tissues will appear normal radiologically. Until
stimulus has been removed.65,66 Once the offending tooth the periodontium is involved, the tooth is usually symp-
has been identified and irreversible pulpitis confirmed, tom-free. Single-rooted teeth usually do not respond
preservation of the pulp is not possible and pulp removal to sensitivity testing. However, in multi-rooted teeth,
is necessary. the pulp may still be partially vital; as a result, sensitivity
testing may produce a negative or positive response,
Pulp necrosis depending on the status of the neural supply adjacent
to the tooth surface being tested. Root canal treatment
This term describes the partial or complete necrosis of is indicated if the diagnosis of pulp necrosis is
the pulp caused by a loss of, or inadequate blood supply. confirmed.

27

Harty’s endodontics in clinical practice

Periapical conditions root canal by instituting root canal treatment and incision
and drainage is also required for any fluctuant swelling
Normal periapical tissues (Fig. 3.19).

The tooth is symptom-free and there is no tenderness to Chronic apical periodontitis
palpation or percussion. Radiological examination will
reveal a normal periodontal ligament space and no evi- Patients may be symptom-free, alternatively, they may
dence of periapical pathosis. report that the tooth feels different or it may be slightly
tender to chewing. Clinically, the tooth may be tender to
Acute apical periodontitis percussion or palpation and does not respond to sensitiv-
ity testing. Radiologically, there may be a widening of the
The tooth in question will be exquisitely tender to touch, periodontal ligament space or more usually, a periapical
biting or percussion. Radiological examination may reveal radiolucency may be present (Fig. 3.20). A ‘phoenix’
a slight widening of the periodontal ligament space. A abscess is an acute exacerbation of chronic apical perio-
negative response to sensitivity testing indicates an endo- dontitis and arises in a tooth with a pre-existing periapical
dontic cause. radiolucency.

Acute periapical abscess Chronic periapical abscess

Patients suffering from acute periapical abscess will usually The tooth is usually symptom-free, not sensitive to biting
present complaining of an intense throbbing pain. The pressure but may ‘feel different’ to the patient upon per-
tooth in question will be very tender to touch, percussion cussion. It is not responsive to pulp sensitivity tests and
and palpation. There may be discernible mobility as the radiologically, there will be a periapical radiolucency.
tooth is elevated from its bony socket. The tooth will Chronic periapical abscess may be distinguished from
not respond to sensitivity tests. An intra or extraoral swell- chronic apical periodontitis because the former will
ing may be present (Fig. 3.19). In severe cases, there may usually be associated with a draining sinus tract. If the
be lymphadenopathy, malaise and the patient may have sinus tract is sited at the gingival margin, there will be a
an elevated temperature. Radiologically, the periapical localized, narrow periodontal pocket. A gutta-percha
tissues may appear normal, or there may be a periapical point may be gently inserted into the sinus tract and a
radiolucency. The abscess will have to be drained via the radiograph taken to track the source and confirm the caus-
ative tooth (Fig. 3.21).

RESTORABILITY

Figure 3.19  An acute periapical abscess related to the If a tooth is to be retained as a functional unit in the
maxillary left first premolar. The palatal swelling will have to dental arch after endodontic treatment, it has to be
be incised and drained, and root canal treatment instituted if restored to both form and function. Therefore, the restor-
the tooth is to be retained. ability of the tooth has to be considered before providing
treatment. If there are any doubts about restorability, it
may be necessary to remove the entire existing restoration
to check.67 Only after it has been established that there
is sufficient sound coronal tooth structure remaining
should endodontic treatment proceed. This approach
has the added benefit of allowing the clinician to visualize
and consider the eventual post-endodontic restoration
required.

Recently, a ‘Tooth Restorability Index’ (TRI) was devised
to assist the clinician in deciding how to restore root
treated tooth.68 Prior to restoration, the tooth is divided
into sextants. The amount of remaining sound coronal
tooth structure in each sextant is given a grade ranging
from 0–3 depending on its quantity, height and width.
The scores from each sextant are then combined, the
resulting score will help guide the clinician in planning

28

Diagnosis Chapter | 3 |

Save tooth

If a tooth is potentially saveable and the patient preference
is for its retention, then treatment should be provided in
the effort to keep the tooth.

Lose tooth

If the prognosis is likely to be poor despite intervention,
or the patient does not want to retain a potentially salvage-
able tooth, then extraction may be necessary

SPECIFIC ENDODONTIC
TREATMENT OPTIONS

Figure 3.20  A mandibular left first molar with chronic apical Pulp monitoring
periodontitis. The tooth is restored with a crown and is
symptom-free but the radiograph reveals a periapical If there is insufficient and inconclusive evidence that
radiolucency. endodontic intervention is required, periodic reviews may
be necessary to monitor pulpal status. A common example
which type of post-endodontic restoration is suitable for is cases of trauma, where teeth have to be reassessed and
the tooth. The restoration of endodontically treated teeth special tests may have to be repeated to evaluate pulpal
is covered in Chapter 15. vitality. The rationale for such an approach should be
explained to the patient and if there are any new develop-
ments, the need for treatment should be reconsidered.

TREATMENT OPTIONS Pulp preservation

Upon reaching a diagnosis, the patient should be advised The aim of this treatment option is to maintain
of the different endodontic treatment options available. pulpal vitality by removing irritants that may provoke
As part of the decision-making process, the advantages, pulpal inflammation. The treatments commonly used to
disadvantages and the prognosis for each treatment option preserve pulp vitality include indirect pulp capping, direct
should be discussed with the patient. The treatment plan pulp capping and pulpotomy. This subject is covered in
should be tailored to the patient’s specific problem, taking Chapter 5.
into account the patient’s preference. In addition, the cli-
nician should be competent and confident in carrying out Pulp extirpation
the treatment plan. If not, the case may be best referred to
a specialist for management (Fig. 3.22). Endodontic case When the vital pulp is irreversibly damaged, its removal
assessment forms69,70 have been devised to help the clini- is inevitable. Pulp extirpation is often the first stage in root
cians evaluate the potential complexity of endodontic canal treatment and a necessary emergency procedure to
treatment. Similar forms have been found to be useful for render the patient pain-free.
assessing the potential complexity of endodontic treat-
ment, therefore helping the general practitioner decide Root canal treatment
whether to refer the patient to a specialist.71
Root canal treatment is needed for teeth with irreversible
Watch and review pulpitis or apical periodontitis. Treatment may be com-
pleted in a single visit if the tooth is not infected, the
If there is no clear diagnosis or the patient is undecided patient prefers and there is sufficient time available for
on treatment, then a more cautious approach may be this approach. Otherwise, the pulp may first have to be
adopted. The tooth is monitored until a definitive diagno- extirpated and another appointment scheduled for
sis or decision on treatment has been reached. If appropri- completion of the root canal treatment. If the tooth is
ate and necessary, for the time being, only symptomatic infected or there is concern about being able to achieve
treatment is provided, for example, analgesics for pain. predictable disinfection of the root canal system, then
more than one visit may be necessary. A successful

29

Harty’s endodontics in clinical practice

AC

BD

Figure 3.21  (A) A buccal sinus tract situated between two mandibular left molars. (B) A periapical radiograph showing
both teeth with suboptimal root fillings. (C) A gutta-percha point is inserted into the sinus tract to trace the source and
(D) a second radiograph taken confirmed the culprit is the mandibular left first molar. From Chong 2004,71 with permission
of Quintessence Publishing Co. Ltd.

treatment outcome should never be sacrificed for the sake surgical and surgical retreatment in Chapters 14 and 10
of procedural expediency. The issue as to whether root respectively.
canal treatment should be completed in one or more visits
is discussed in Chapter 7. LEARNING OUTCOMES

Root canal retreatment Following completion of this chapter, the reader should
be able to understand and discuss the:
Although a tooth has already been root treated, if there
are signs and symptoms indicative of treatment failure and • systematic approach needed to achieving a
the tooth is to be retained, then root canal retreatment is
required72 (Fig. 3.18). Retreatment may be via a non-sur- diagnosis
gical or a surgical approach. There is coverage on non-
• importance of deferring irreversible, invasive

treatment until there is a clear diagnosis

30

Diagnosis Chapter | 3 |

• special tests or additional investigations required to

help confirm the provisional diagnosis

• conditions associated with pulpal or periapical

diseases and their differential diagnosis

• general and specific endodontic treatment

options

• process of formulating a treatment plan based on

the diagnosis

• appropriate referral to a specialist if a diagnosis

cannot be established or complex endodontic
treatment is required.

Figure 3.22  A complex endodontic case that may be best
referred to a specialist for management. Apart from
extensive caries, especially in the second molar, both teeth
have complicated root morphology and significant canal
sclerosis; also, access to these teeth will not be easy.

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4Chapter  

Pulp space anatomy and access cavities

A.D.M. Watson

CHAPTER CONTENTS 35 SUMMARY
35
Summary 36 Knowledge of pulp space anatomy is essential to achieving
Introduction 38 the objectives of endodontic treatment. The advent of
Nomenclature 38 newer imaging techniques including three-dimensional
Accessory and lateral canals 38 tomography has revealed and confirmed the complex
Location of apical foramina 39 and divergent anatomy of the pulp space. Classical, pre-
Variations in pulp space anatomy 40 conceptualized access cavity designs are informative in the
Effects of tertiary dentine on pulp space 40 understanding of pulp space anatomy. However, they
Pulp space anatomy and access cavities 42 have been replaced by emergent and customized access
42 cavity designs, prepared according to treatment require-
Maxillary central and lateral incisors 42 ments. Unnecessary and excessive destruction of tooth
Maxillary canine 43 tissue during access cavity preparation remains unwar-
Maxillary first premolar 45 ranted. The wider adoption of magnification and enhanced
Maxillary second premolar 45 illumination, especially the clinical use of an operating
Maxillary first molar 46 microscope, is invaluable, greatly aiding access cavity
Maxillary second molar 47 preparation and allowing the detailed examination of the
Maxillary third molar 47 pulp space.
Mandibular central and lateral incisors 48
Mandibular canine 48 INTRODUCTION
Mandibular premolars 49
Mandibular first molar 49 The major factors involved in the development of apical
Mandibular second molar 49 periodontitis are loss of integrity of coronal tooth sub-
Mandibular third molar 50 stance and the entry of microorganisms into the dentine
Pulp space anatomy of primary teeth 50 and pulp space. The primary aim of root canal treatment
Primary incisors and canines 51 is the removal and exclusion of these microorganisms,
Primary molars 51 their substrates and products from the pulp space and
Apical closure surrounding dentine. Current practice involves the chem-
Learning outcomes omechanical cleaning, followed by the complete sealing
References of the pulp space. In addition, the need for a good coronal
restoration is integral to reducing the risk of pulp space
© 2009 Elsevier Ltd, Inc, BV recontamination.
DOI: 10.1016/B978-0-7020-3156-4.00007-3
35

Harty’s endodontics in clinical practice

A clear understanding of the anatomy of human teeth chamber projects into well-developed pulp horns. In mul-
is an essential prerequisite to achieving the objectives of tirooted teeth the depth of the pulp chamber depends
adequate access, thorough cleaning, effective disinfection, upon the position of the root furcation and may extend
and complete obturation of the pulp space. Many of the beyond the anatomical crown. In young teeth, the outline
problems encountered during endodontic treatment occur of the pulp chamber resembles the shape of the exterior
because of the pulp response to irritation and an inade- of the dentine. With age, the dentinal tubules and the
quate understanding of the pulp space anatomy. Both pulp chamber become reduced in size by the laying down
students and clinicians need to familiarize themselves of intratubular dentine, secondary dentine and tertiary
with the intricacies, complexities and aberrations that are dentine, particularly in areas where there has been caries,
likely to occur within the pulp space. The importance of tooth wear and exposure to operative treatment (Fig. 4.2).
developing a visual picture of the expected locations and The pulp chamber may then become irregular in outline.
numbers of canals in a particular tooth cannot be With age, there is also a gradual decrease in pulp space
overemphasized. volume, the number of nerves, blood vessels and cells
within, but an increase in the fibrous and mineral compo-
The internal anatomy of human teeth has been studied nents. The rate at which the pulps age varies from one
by many investigators, who have provided a valuable tooth to another, and from one patient to another. Calcific
insight into the size, shape and form of the pulp space. changes can lead to the pulp space appearing entirely
Methods of study have included replication techniques,1,2 obliterated radiologically. A residual canal, although
ground sections,3 clearing techniques4,5,6 and radiogra- radiologically unidentifiable, almost certainly remains
phy.7–12 Clinical radiographs show the forms of roots within the root as a pathway for microbes to reach the
and pulp canals in two planes only. A third plane exists apex and cause periapical changes.
in a buccolingual direction. The pulp space volume is
invariably much greater than the clinical radiograph The pulp of root canals is continuous with the
would suggest. Micro-computed tomography has allowed pulp chamber and normally the greatest diameter is at
the appreciation of pulp space anatomy in three- the pulp chamber level. Because roots tend to taper
dimensions (Fig. 4.1). More recently, Cone Beam Com- towards their apex, the canals also have a tapering
puted Tomography (CBCT) has increased our knowledge form which is constricted at the end, the apical constric-
of the pulp space13,14 and allowed the identification of tion, before emerging at the apical foramina, near the
missed anatomy. root end; rarely do the foramina open at the exact ana-
tomical apex of the tooth. During root development, the
NOMENCLATURE pulp and periodontal tissues become separated, maintain-
ing neural and vascular connections through the apical
Anatomically, the dental pulp space is surrounded foramina.
by dentine to form the pulp-dentine complex. Dentine
forms the bulk of the mineralized tissue of the tooth. The pulp space is complex and root canals may divide
The dentinal tubules, which are interconnected, make up and rejoin, and possess forms that are considerably more
20–30% of the total volume of dentine.15 The number involved than many textbooks of anatomy have implied.
of tubules per square millimetre more than doubles and Many roots have additional canals and a variety of canal
the area occupied by tubules increases three-fold from the configurations. Eight separate pulp space configurations
dentine near the amelodentinal junction, to that near have been identified6 (Fig. 4.3). In the simplest form, each
the pulp.16 These differences have a significant clinical root has a single canal and a single apical foramen (Type
effect on the permeability of dentine. It is now realized I). Commonly, however, other canal complexities are
that the dentinal tubules are an important reservoir of present and exit the root as one, two or more apical canals
microorganisms when pulpal necrosis occurs.17 A direct (Types II–VIII).
route of contamination from unclean root canals into the
periapical tissues may be created by the exposure of Since roots tend to be broader buccolingually than
infected tubules following root-end resection during they are mesiodistally, the pulp space is similarly oval in
apical surgery.18,19 cross-section. The diameter of the root canal decreases
towards the apical foramen and reaches its narrowest
The pulp space is divided into two parts: the pulp point 1.0–1.5  mm from the foramen. This point, the
chamber, which is usually described as that portion within apical constriction lies within dentine just prior to the first
the crown; and the pulp canal or root canal, which lies layers of cementum and is the narrowest point to which
within the confines of the root. The pulp chamber is a the canal tapers. During root development the apical part
single cavity, the dimensions of which vary according to of the pulp is described as being ‘open’. As the tooth
the outline of the crown and the structure of the roots. matures, the funnel-shaped foramen closes and constricts
Thus if the crown has well-developed cusps the pulp to a normal root shape with a small apical foramen.
The position of the apical foramen may also be altered,
relative to the root apex with the deposition of secondary
cementum.

36

Pulp space anatomy and access cavities Chapter | 4 |

A

B
C
Figure 4.1  Three-dimensional images reconstructed from micro-computed tomography data; cross sections at various levels
indicated by corresponding lines. (A) Maxillary molar. (B) Mandibular molar. (C) Cellular arrangement of odontoblast layer.
From Peters 2008,38 with permission of Quintessence Publishing Co. Ltd.

37