ENDODONTICS-Endodontics in Clinical Practice, 6e

Harty’s endodontics in clinical practice

allow the more slowly growing progenitor cells from the some trends and correlations, but even these findings
bone and periodontal ligament to repopulate the root may only be applicable to specifically controlled
surface and produce a new connective tissue attachment. cases.105,143
The objectives of membrane application in endodontic
surgery are the following:140 Success (complete healing) with periradicular surgery
has been reported to range from very low levels to levels
• To facilitate tissue regeneration by creating an as high as 96.8%143 using mixed populations, at frequently
less than ideal percentages of review examinations and
optimum environment (stable and protected short follow-up periods. With longer follow-up periods of
wound). up to 8 years, a success rate of 91.5% has been achieved,3
which correlates closely with other long-term prospective
• To exclude undesirable, fast-proliferating cells that studies (91.2%).144 Whilst significant variability in results
makes comparisons of studies questionable, the identifica-
interfere with desired tissue regeneration. tion of factors that have contributed to the success or
failure of periradicular surgery is essential, and these
A classification for guided-tissue regeneration (GTR) should be integrated into all phases of case assessment
application in endodontic surgery based on the location, and treatment.145 Often the aetiology of failure may be
extent and nature of the lesion has been proposed: difficult to identify, and may encompass a multitude of
factors. For periradicular surgery, most failures can be
• Class I – bony defects located at the apex. attributed to specific causes. At the same time, when
• Class II – apical lesions with concomitant marginal failure cannot be explained, uncertain aetiological factors
and treatment may be speculated. Table 10.6 lists the
lesions. aetiological factors often cited as valid, or uncertain in the
failure of periradicular surgery.
• Class III – lateral or furcation lesions with or
Table 10.6  Factors influencing success or failure of
without a marginal lesion. periradicular surgery

Two main types of membrane have been used, absorbable Valid causes for surgical failure
and non-absorbable. The first commercially available
membrane was an expanded polytetrafluoroethylene Failure to debride the root canal space thoroughly.
(ePTFE) non-absorbable membrane (GORE-TEX, W.L.
Gore & Associates, Flagstaff, AZ, USA). The use of GORE- Failure to seal the root canal space adequately.
TEX membrane necessitated a second surgical procedure
to remove it. With the development of absorbable mem- Tissue irritation from toxic root canal or root-end fillings.
branes, single visit surgical procedures became possible.
Studies have subsequently shown that there is no signifi- Failure to manage root canal or root-end materials
cant difference in the healing with either type of properly.
membrane.141
Superimposition of periodontal disease.
The absorbable membranes can be either natural mate-
rials such as collagen (Biomend, Zimmer Dental, Carlsbad, Longitudinal root fracture.
CA, USA or Bio-Gide, Geistlich, Wolhusen, Germany)
or synthetic polymers such as polyglactin. The natural Recurrent cystic lesion.
materials are absorbed by enzymatic action while the
synthetic materials are absorbed by hydrolysis. The use Improper management of the supporting periodontium.
of an absorbable membrane (Bio-Gide) in combination
with a bone substitute material (Bio-Oss, Geistlich) Uncertain causes for surgical failure
has been shown to stimulate substantial new bone and
cementum formation with Sharpey’s fibre attachment.142 Infected dentinal tubules.
Histological evaluation suggests that the combined
approach compares favourably with other regenerative Infected periradicular lesion.
treatment.
Failure to use antibiotics when indicated.
TREATMENT OUTCOME – AETIOLOGY
AND EVALUATION Accessory or lateral canals.

Although many studies have attempted to determine Loss of alveolar bone.
success–failure rates for periradicular surgery, none have
been able to integrate fully all parameters of evaluation Root resorption.
with techniques performed, materials used, patient
compliance, clinician expertise, variability and interpreta- Timing of root canal filling (before or during surgery).
tive skills. Attempts at multivariate analysis have provided
Type of root-end filling.

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Table 10.7  Clinical evaluation of success and failure Table 10.8  Radiological evaluation of success
Clinical success and failure
No tenderness to percussion or palpation. Radiological success
Normal mobility and function. Normal periodontal ligament width or slight increase.
No sinusitis or paraesthesia. Normal lamina dura or elimination of radiolucency.
No sinus tract or periodontal pocket. Normal to fine-meshed osseous trabeculae.
No infection or swelling. No resorption evident.
Adjacent teeth respond as expected to stimuli. Radiological uncertainty
Minimal to no scarring or discolouration. Slight increase in periodontal ligament width.
No subjective discomfort. Slight increase in width of lamina dura.
Clinical uncertainty Size of radiolucency static or slight evidence of repair.
Sporadic vague symptoms. Radiolucency is circular or asymmetric.
Pressure sensation or feeling of fullness. Extension of the periodontal ligament into radiolucency.
Low grade discomfort on percussion, palpation, or Evidence of resorption.
chewing. Radiological failure
Discomfort with tongue pressure. Increased width of the periodontal ligament and lamina
Superimposed sinusitis focused on treated tooth. dura.
Occasional need to use analgesics. Circular radiolucency with limited osseous trabeculae.
Clinical failure Symmetrical radiolucency with funnel-shaped borders.
Persistent subjective symptoms. Evidence of resorption.
Discomfort to percussion and/or palpation.
Recurrent sinus tract or swelling. ently normal radiological appearance, a clinically symp-
Evidence or irreparable tooth fracture. tom-free tooth may exhibit histopathological changes in
Excessive mobility or progressive periodontal breakdown. the periradicular tissues. This is especially true adjacent
Inability to chew on the tooth. on resected root surfaces which are difficult to assess
radiologically.

Evaluation of success or failure following root-end RETREATMENT OF SURGICAL
surgery is limited to clinical and radiological examina- PROCEDURES
tions. Clinical criteria for success or failure are used most
commonly and in conjunction with the radiological find- Not all surgery is successful, but when a case has been
ings. The clinical outcome is classified into one of three identified as failing, it is necessary to use all tests and
categories at the time of review (Table 10.7). Patient information available to determine the cause prior to
assessment, however, must be made in conjunction with further surgery. Table 10.9 lists some of the more common
both clinical and radiological parameters of evaluation unsuspected, anatomical and technical causes for failure.
(Table 10.8). If the only goal of periradicular surgery is to Not all of these causes are amenable to further surgery,
retain the tooth in adequate clinical function, then many and a tooth may require extraction and prosthetic
cases can be classified as successful. Many factors, however, replacement.
such as case selection, evaluator bias, and patient factors
can skew levels of success or failure. Likewise, many clini- Very few studies have evaluated the results of per­
cally symptom-free teeth may have histopathological iradicular surgery that was performed subsequent to
changes at the root apices along with minimal or extensive previous surgical failure.43,146 The success rates of
radiological changes. Even in the presence of an appar- repeat surgery were 50% or less with little subsequent
alteration in healing after one year, but these figures

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Harty’s endodontics in clinical practice

Table 10.9  Causes of surgical failure of the canal space as possible and to seal thoroughly the
coronal aspects of the root canal system before resorting
Unsuspected to surgical intervention. Failing to adhere to this will inevi-
Root fracture not readily visible. tably result in failure.

Post-hole perforation, especially on the buccal or lingual LEARNING OUTCOMES
surface.
Upon completion of this chapter, the reader should be
Instrument perforation coronal to the resected root end. able to describe and discuss the:

Persistent infection in the apically resected tubules. • indications for periradicular surgery and the

Corrosion of previously placed amalgam root-end filling. preoperative assessment process

Anatomical • key instruments and their usage in surgical
Fenestrations or dehiscences – loss of marginal bone.
endodontics
Aberrant root anatomy or canal space.
• importance of tissue anaesthesia and haemostasis
Proximity of root of adjacent teeth. • management of the soft tissue, including tissue flap

Proximity of maxillary sinus. design, tissue incision, elevation and reflection

Technical • procedures for osseous entry and root identification
Poor canal cleaning and filling.
in the various tooth groups
Inadequate root-end resection.
• rationale and techniques for the removal of soft
Inadequate root-end preparation and filling.
tissue lesions and tissue biopsy
Toxicity of root-end filling material.
• rationale, techniques and instruments for root-end
Improper soft tissue management.
resection, root-end cavity preparation and root-end
relate to discontinued techniques. In a recent, systematic filling
review and meta-analysis of the outcomes of resur-
gery14,63,105 there was a near equal distribution of the cases • root-end filling materials available and the choice of
between the three outcome groups: 35.7 % healed success-
fully, 26.3% healed with uncertain results and 38% did material
not heal.
• techniques for primary closure of the surgical site to
The primary reason for failure following periradicular
surgery is the presence of infected debris in uncleaned and minimize postoperative sequelae
poorly filled canal spaces.14,105 The primary cause of failure
with root canal treatment has been identified as coronal • importance of the postoperative examination and
leakage due to poor quality of the coronal restoration.84,147
Therefore, it is essential to access, clean and fill as much case review, including radiographic assessment

• implications and anatomical concerns when

considering periradicular surgery of particular teeth

• repair of tooth/root perforations and the rationale

for tooth replantation or transplantation

• rationale for, and clinical techniques of, regenerative

procedures that may be used in conjunction with
periradicular surgery

• importance of assessing treatment outcome,

including identification of adverse aetiological
factors that may require the revision of previous
surgical procedures.

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116. Nicholls E. Treatment of 128. Dahlin C, Linde A, Gottlow J,
106. Reit C. Decision strategies in traumatic perforations of the Nyman S. Healing of bone
endodontics: on the design of a pulp cavity. Oral Surgery defects by guided tissue
recall program. Endodontics & 1962;15:603–612. regeneration. Plastic &
Dental Traumatology 1987;3: Reconstructive Surgery 1988;81:
233–239. 117. Oswald RJ. Procedural accidents 672–676.
and their repair. Dental Clinics
107. Finn MD, Schow SR, of North America 1979;23: 129. Dahlin C, Gottlow J, Linde A,
Schneiderman ED. Osseous 593–616. Nyman S. Healing of maxillary
regeneration in the presence of and mandibular bone defects
four common hemostatic agents. 118. Sinai IH. Endodontic using a membrane technique. An
Journal of Oral & Maxillofacial perforations: their prognosis and experimental study in monkeys.
Surgery 1992;50:608–612. treatment. Journal of the Scandinavian Journal of Plastic &
American Dental Association Reconstructive Surgery & Hand
108. Pinto VS, Zuolo ML, Mellonig JT. 1977;95:90–95. Surgery 1990;24:13–19.
Guided bone regeneration in the
treatment of a large periapical 119. Young GR. Contemporary 130. Douthitt JC, Gutmann JL,
lesion: a case report. Practical management of lateral root Witherspoon DE. Histologic
Periodontics & Aesthetic perforation diagnosed with the assessment of healing after the
Dentistry 1995;7:76–81; quiz 2. aid of dental computed use of a bioresorbable membrane
tomography. Australian in the management of buccal
109. Benenati FW, Roane JB, Biggs JT, Endodontic Journal 2007;33: bone loss concomitant with
Simon JH. Recall evaluation of 112–118. periradicular surgery. Journal of
iatrogenic root perforations Endodontics 2001;27:404–410.
repaired with amalgam and 120. American Association of
gutta-percha. Journal of Endodontists. Glossary of 131. Blomlöf L, Lindskog S. Cervical
Endodontics 1986;12:161–166. endodontic terms. 7th ed. root resorption associated with
Chicago, IL, USA: American guided tissue regeneration: a case
110. Biggs JT, Benenati FW, Sabala CL. Association of Endodontists; report. Journal of Periodontology
Treatment of iatrogenic root 2003. 1998;69:392–395.

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132. Uchin RA. Use of a bioresorbable human studies. Periodontology bone – Bio-Oss composite graft
guided tissue membrane at an 2000 1993;1:26–35. and a Bio-Gide membrane.
adjunct to bony regeneration in International Journal of
cases requiring endodontic 138. Nyman S, Gottlow J, Karring T, Periodontics & Restorative
surgical intervention. Journal of Lindhe J. The regenerative Dentistry 2001;21:109–119.
Endodontics 1996;22:94–96. potential of the periodontal
ligament. An experimental study 143. Rubinstein RA, Kim S. Short-term
133. Zenobio EG, Shibli JA. Treatment in the monkey. Journal of observation of the results of
of endodontic perforations using Clinical Periodontology 1982;9: endodontic surgery with the use
guided tissue regeneration and 257–265. of a surgical microscope and
demineralized freeze-dried bone Super-EBA as root-end filling
allograft: two case reports with 139. Gottlow J, Nyman S, Karring T, material. Journal of Endodontics
2–4 year post-surgical Lindhe J. New attachment 1999;25:43–48.
evaluations. Journal of formation as the result of
Contemporary Dental Practice controlled tissue regeneration. 144. Zuolo ML, Ferreira MO,
2004;5:131–141. Journal of Clinical Gutmann JL. Prognosis in
Periodontology 1984;11: periradicular surgery: a clinical
134. Zorzano LA, Sanchez AL, 494–503. prospective study. International
Chacartegi JE, et al. Guided tissue Endodontic Journal 2000;33:
regeneration procedure applied to 140. von Arx T, Cochran DL. Rationale 91–98.
the treatment of endodontic- for the application of the GTR
periodontal disease: analysis of a principle using a barrier 145. Lim LM, Pascon EA, Skribner J,
case. Quintessence International membrane in endodontic surgery: et al. Clinical, radiographic, and
1997;28:87–91. a proposal of classification and histological study of endodontic
literature review. International treatment failures. Oral Surgery,
135. Melcher AH. On the repair Journal of Periodontics & Oral Medicine, Oral Pathology
potential of periodontal tissues. Restorative Dentistry 2001;21: 1991;71:603–611.
Journal of Periodontology 127–139.
1976;47:256–260. 146. Nordenram A, Svardstrom G.
141. Caffesse RG, Mota LF, Quinones Results of apicectomy. Swedish
136. Karring T, Nyman S, Lindhe J. CR, Morrison EC. Clinical Dental Journal 1970;63:593–604.
Healing following implantation comparison of resorbable and
of periodontitis affected roots non-resorbable barriers for 147. Ray HA, Trope M. Periapical
into bone tissue. Journal of guided periodontal tissue status of endodontically treated
Clinical Periodontology 1980;7: regeneration. Journal of Clinical teeth in relation to the technical
96–105. Periodontology 1997;24: quality of the root filling and the
747–752. coronal restoration. International
137. Karring T, Nyman S, Gottlow J, Endodontic Journal 1995;28:
Laurell L. Development of the 142. Camelo M, Nevins ML, Lynch SE, 12–18.
biologic concept of guided tissue Shenk RK. Periodontal
regeneration – animal and regeneration with an autogenous

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Chapter 11 

Endodontics in primary teeth

A. O’Donnell

CHAPTER CONTENTS 197 INTRODUCTION
197
Summary 198 The basic aims of endodontic treatment of primary
Introduction 199 teeth are similar to those for the permanent dentition:
Treatment of primary teeth 200 prevention or treatment of apical periodontitis, as well
200 as the relief of associated symptoms including pain. It
Indirect pulp capping 201 is generally accepted that primary molar teeth should be
Direct pulp capping 203 retained until they exfoliate naturally to avoid loss of
Pulpotomy 204 space and crowding of the permanent dentition.
Medicaments 205
Pulpectomy Although the response of primary teeth to infection
Learning outcomes is similar to that of adult teeth, morphological and
References physiological differences exist between primary and
permanent teeth resulting in varying techniques for
SUMMARY endodontic treatment. In addition, extra care must always
be taken when carrying out endodontic treatment,
Endodontic treatment for deciduous teeth can be especially on deciduous incisors. Parents must be warned
challenging due to the morphology of the root canal of potential damage to the underlying permanent succes-
system, difficulties with correct diagnosis and behaviour sor and the risks versus benefits discussed in full. A referral
management issues associated with a young patient. to a specialist paedodontic unit is sometimes necessary
The vital, non-infected pulp should be preserved when for endodontic management of primary teeth. When
appropriate. As with any endodontic treatment, the elimi- deciding on a suitable treatment plan for primary teeth,
nation of infection is critical to a successful outcome. the clinician must consider whether the tooth should
There is a move away from formocresol and most paedi- be saved with endodontic treatment or if extraction
atric dentists now prefer to use alternative medicaments. would be more advantageous. The following should be
Root canal treatment of the infected primary tooth is, considered:
often, the best treatment option but it may be challenging
and impractical to perform. A referral to a specialist may Factors related to the patient
sometimes be necessary for endodontic management of
primary teeth. • Patient cooperation – if a child is uncooperative or

unable to cope with treatment in the dental chair,
careful thought must be given to the potential
benefits versus the risks of carrying out endodontic
treatment under general anaesthesia. Although
endodontic treatment enjoys a high success rate, the
outcome cannot be guaranteed when there are
compounding factors. If failure occurs, the child may

© 2009 Elsevier Ltd, Inc, BV 197
DOI: 10.1016/B978-0-7020-3156-4.00014-0

Harty’s endodontics in clinical practice

be subjected to a repeat general anaesthetic to has affected two-thirds or more of the roots, then
remove the tooth. endodontic treatment is not a sensible option as the
tooth is close to being exfoliated.
• Medical history – certain medical conditions will
TREATMENT OF PRIMARY TEETH
determine whether endodontic treatment should be
undertaken. Children who are immunosuppressed, Primary teeth differ morphologically from their perma-
e.g. receiving chemotherapy, are not suitable nent successors both in shape and size; pulp space
candidates for endodontic treatment as there is the anatomy of primary teeth is covered in Chapter 4. In
concern regarding a potential source of infection in general, the enamel and dentine are thinner than in a
the deciduous tooth. In patients at risk of infective permanent tooth. Pulpal changes in response to caries,
endocarditis, endodontic treatment in deciduous therefore, occur more rapidly and even lesions that appear
teeth is also not recommended. However, very minimal clinically can extend into the pulp (Fig.
endodontic treatment may be the treatment of 11.1). Primary molars have fine tapered roots which are
choice in patients with coagulation disorders to flattened mesiodistally to enclose a ribbon-like root canal
avoid the risk of bleeding associated with an system and their pulp chambers are relatively larger than
extraction. Children whose medical history permanent teeth. The single root canal may become par-
contraindicates general anaesthesia, and who are tially calcified with age,2 to produce several intercommu-
unable to tolerate an extraction under local nicating canals, thus making instrumentation of the
anaesthesia, may sometimes be able to cope with radicular pulp space difficult. Many lateral canals have
root canal treatment under local anaesthesia. For any been reported to exist in the furcation of primary molar
child with a relevant medical history, the medical teeth,3 and these may contribute to the early spread of
team should be consulted before deciding on the infection from the pulp chamber to the interradicular
best treatment option. area.4

• Irregular attenders and poor parental attitude to The correct diagnosis of pulp disease is important as this
will determine which endodontic treatment procedure
dentistry – this may lead the clinician to decide will be required. The diagnosis is dependent on the com-
against endodontic treatment due to the inability to bination of a good history, clinical and radiological exami-
carry out regular clinical and radiological follow-up. nation. A clear history of clinical symptoms is especially
difficult to obtain in young patients because they are
Factors related to the dentition usually unable to give an accurate pain history, and paren-
tal report is usually relied upon. Symptoms of irreversible
• Extent of dental decay – if the decay is extensive and damage will include a history of spontaneous pain, severe
pain at night and pain on biting. The clinical examination
restoration following endodontic treatment will be should begin with assessing the extent of the caries. It has
difficult or impossible then extraction is the been reported that in the majority of primary molars with
treatment of choice. marginal ridge breakdown there is pulpal inflammation
involving the pulp horn adjacent to the carious lesion.5
• Extent of periapical infection – if gross, pathological The presence of abnormal tooth mobility, intraoral swell-
ing, discharging sinus tracts and tenderness to pressure
resorption has occurred or the infection is severe, will also indicate periapical pathosis. In primary teeth,
extraction may be the best option. sensitivity testing has been shown to be an unreliable
guide to the histological status of the pulp,6,7,8 so a com-
• Condition of the rest of the dentition – if this is bination of the history, clinical and radiological examina-
tion provides an indication of the pulpal status.
poor and patient’s motivation to change diet and
improve oral hygiene is not deemed to be high, If the child is cooperative, preoperative radiological
extraction is usually recommended. examination is invaluable. This provides information
regarding root morphology, periapical pathosis, resorp-
• Hypodontia – If there is no permanent successor, tion and calcifications, aiding diagnosis and assessment of
any local contraindications to endodontic treatment. The
endodontic treatment may be the best option in treatment techniques that have been advocated for use on
order to keep the space for a future bridge or primary teeth may be grouped as follows:
implant.1 However, it is important to obtain
orthodontic advice beforehand; the deciduous tooth • indirect pulp capping
may be best removed and, provided the timing is • direct pulp capping
right, the space may be used orthodontically.

• Balancing in primary canines and first molars – if

the contralateral tooth has been lost, it may be
preferable to carry out a ‘balancing’ extraction rather
than perform endodontic treatment, especially when
the arch is crowded.

• Remaining natural lifespan of the tooth – it is

generally accepted that primary molar teeth should
be retained until they exfoliate naturally to avoid
loss of space and crowding of the permanent
dentition. However, if physiological root resorption

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Endodontics in primary teeth Chapter | 11 |

AB

Figure 11.1  Carious deciduous molar. (A) The carious lesion appears minimal clinically. (B) Pulpal exposure following total
caries removal. Reproduced courtesy of M.Vaidyanathan.

• pulpotomy ciated swelling, tenderness to biting, or abnormal tooth
• pulpectomy. mobility. Likewise, preoperative radiographs must be
examined for pathological root resorption, pulp calcifica-
In all cases, the administration of local anaesthesia and tions or periapical radiolucency, which if present, would
adequate tooth isolation, preferably with rubber dam, necessitate less conservative treatment.
are advised. For vital maxillary teeth, infiltration anaesthe-
sia is usually satisfactory, whereas a nerve block or intrali- At the initial visit, all soft carious dentine is removed
gamentary injection may be more suitable for mandibular with a bur in a slow-speed handpiece or by hand with an
molar teeth. It cannot be overemphasized that a successful excavator. The amelodentinal junction must be free from
treatment outcome is dependent on correct diagnosis, all softened carious dentine. The area of dentine over the
appropriate technique and the provision of a definitive site of a potential pulpal exposure is covered with a layer
restoration, ideally a preformed metal crown, which will of hard setting cement containing calcium hydroxide
provide a good coronal seal.9 All primary teeth that have (e.g. Dycal, Dentsply, Weybridge, Surrey, UK) and sealed
had an endodontic procedure carried out should be fol- with an overlying structural base of a quick-setting, rein-
lowed up clinically and radiographically. forced zinc oxide–eugenol preparation (e.g. IRM, Dent-
sply) or glass ionomer cement. A success rate of 92% for
Indirect pulp capping indirect pulp capping with calcium hydroxide in primary
incisors followed for 42 months has been reported,13 and
This is the term used to describe the placement of a dress- 96% in primary molars after 1 year.14 Alternatively, an
ing over residual carious dentine in an attempt to allow adhesive resin system may be used, directly over the
secondary dentine to be formed within the pulp chamber.10 dentine which has shown to have a success rate of 96%
Exposure of the pulp is, therefore, avoided in teeth with compared with 83% for calcium hydroxide.15 Other
deep carious lesions when there is no clinical or radiologi- studies have shown success when glass ionomer is placed
cal evidence of pulpal or periapical disease. Removal of over the dentine,16 which offers the additional benefit of
caries from the lateral wall ensures that there is an ade- fluoride release. The final restoration can then be placed.
quate seal between the tooth and the restoration so that The indirect pulp cap technique has been shown to be
microbes are deprived of the nutrients necessary for their clinically more successful than formocresol pulpotomy,17,18
survival.11,12 Contraindications to this method of treat- and therefore, offers an alternative to the pulpotomy
ment include any evidence of an irreversibly inflamed or technique. Some authors have advocated a two-stage
necrotic pulp such as a history of spontaneous pain, asso- procedure where the tooth is re-opened 3 months later
and further caries removal is performed.18 Due to the

199

Harty’s endodontics in clinical practice

ration, the tooth should be monitored clinically and radi-
ologically for any signs of subsequent pulp necrosis or
extensive resorption, indicative of treatment failure.

Figure 11.2  Pulp cap with calcium hydroxide. Reproduced Pulpotomy
courtesy of T.Kandiah.
Vital (full coronal) pulpotomy involves the removal of the
high success of the one-stage indirect pulp cap, this is no entire coronal pulp that has undergone irreversible inflam-
longer necessary and regular review of tooth vitality is matory changes or necrosis, leaving remaining healthy
preferable to subjecting the patient to subsequent re-entry vital tissue intact within the root canal system. The cut
into the tooth. radicular pulp stumps are covered with a medicament
which will result in either healing or ‘fixation’ of the tissue
Direct pulp capping beyond the interface of dressing and radicular pulp. Vital
pulpotomy provides the most suitable method for treating
Direct pulp capping is generally not advocated for primary carious exposures in primary teeth without a history of
teeth due to limited evidence of success in the literature. spontaneous pain, swelling, sinus tract, any evidence of
Inflammation within the pulp can persist and is followed internal or external root resorption, or periapical pathosis.
by necrosis or internal resorption. The only possible appli- Its success is dependent on correct diagnosis, control of
cation of this technique is when pulp tissue has been haemorrhage from the radicular pulp and achieving an
mechanically exposed as a result of cavity preparation,19 excellent coronal seal. A preformed metal crown is the
or when the tooth is close to exfoliation.20 Calcium final restoration of choice as this minimizes the risks of
hydroxide is placed on the exposure and encourages for- tooth fracture and microleakage, and hence enhances the
mation of a dentine bridge below the exposure site in an prognosis.
attempt to maintain pulp vitality (Fig. 11.2). The tech-
nique should not be used for carious exposures. The basic technique consists of the following steps:

The exposure site should be gently irrigated with a non- • Local anaesthesia and adequate isolation.
irritant solution, e.g. saline, to remove any debris that may • Caries removal.
impede healing and also to keep the pulp moist. The • Extend cavity so that entire roof of the coronal pulp
capping material should be flowed gently over the expo-
sure and allowed to set. Various capping materials have chamber is removed.
been employed. Calcium hydroxide used alone or in con-
junction with zinc oxide–eugenol, has been most widely • Rose head bur in a slow-speed handpiece or a hand
investigated.21,22 The use of dentine bonding systems has
also been advocated and promising results have been excavator to remove coronal pulp tissue.
reported.19,23 The advantage is that a polymer film can be
layered over an exposure site without displacing the pulp, • Control haemorrhage with sterile cotton wool
and onto surrounding dentine where it permeates the
tubules. Further work is required before these materials pledgets (if bleeding continues this may mean that
can be recommended as capping agents. A more promis- initial diagnosis is incorrect and the pulp is
ing material is Mineral Trioxide Aggregate (MTA), which irreversibly damaged, so pulpectomy is the treatment
is biocompatible and has good sealing properties.24 of choice).
Favourable results have been reported for MTA direct pulp
capping on deciduous molars compared with calcium • Placement of pulpotomy medicament (Fig. 11.3A).
hydroxide;25 and clinical case reports have also supported • Coronal restoration of the tooth (Fig. 11.3B,C).
the use of MTA.26 Following pulp capping and final resto- • Follow-up (Fig. 11.3D).

Electrosurgery may be used for pulpotomy procedures to
either remove the pulp tissue or to control haemorrhage;
the main advantage is that the need for any potentially
toxic medicament can be avoided. However, it was
reported that when electrosurgery was used to remove the
entire coronal pulp and treat the remaining stumps, root
resorption occurred.27 An alternative method may be to
remove the coronal pulp mechanically and treat the
remaining pulp stumps electrosurgically28 in order to
avoid excessive heat dissipation. Although a clinical and
radiological success rate of 99% has been demonstrated
at 2 years,29 the electrosurgical pulpotomy technique is
still experimental and not widely adopted. Lasers have
also been suggested as an alternative instrument but
some studies have shown carbonization, necrosis and
inflammation of the pulp with little evidence of repair.19,30,31
A study on laser pulpotomy versus the formocresol

200

Endodontics in primary teeth Chapter | 11 |

Medicament
Vital pulp

A C
Stainless steel crown

Zinc oxide-eugenol

Vital pulp

D
B

Figure 11.3  Vital pulpotomy. (A) Following caries and coronal pulp removal, medicament is placed; (B) the pulp chamber is
then filled with zinc oxide-eugenol cement and the tooth restored with a preformed metal crown (based on the original
drawings by A Muir). (C) Clinical view of a preformed stainless steel crown. (D) Example of a follow-up radiograph.
Reproduced courtesy of M.Vaidyanathan.

technique carried out on caries-free primary molar teeth, with decay involving the pulp found that the evidence
which were scheduled for extraction reported comparable available did not support the superiority of one type of
results.32 Due to limited evidence, the expense involved treatment over another.33 Therefore, the choice of treat-
and the success of alternative techniques, lasers are rarely ment is very much dependent on clinical presentation and
used for pulpotomies in children. the individual operator.

Medicaments Formocresol

Medicaments are used in endodontic treatment of primary Buckley34 formulated a solution containing equal parts
teeth as wound dressings, tissue fixatives, disinfectants and of formalin and tricresol. A commercial solution contain-
inflammatory suppressants. A systematic review of the lit- ing 19% formaldehyde, 35% cresol in a glycerine/water
erature on the relative effectiveness of various medica- vehicle (Buckley’s formocresol, Cosby laboratories,
ments and techniques for treating primary molar teeth Burbank, CA, USA), was later developed as a suitable

201

Harty’s endodontics in clinical practice

medicament for the treatment of pulpally exposed primary Figure 11.4  Ferric sulphate pulpotomy. The appearance of
teeth. The aim of this treatment technique is to fix the the pulp stumps following application of this medicament.
coronal portion of the radicular pulp and to maintain Reproduced courtesy of T.Kandiah.
vitality of the remaining apical portion.35,36 Formocresol
acts through its aldehyde group and binds to the amino Although glutaraldehyde was proposed as a replacement
acids of protein and bacteria to prevent autolysis and for formocresol, questions remain about its safety.36 On a
hydrolysis so rendering tissue inert.37 weight-for-weight basis there is little difference in toxicity
between formocresol and glutaraldehyde.55
Over the years, there has been increasing concern about
the toxicity, both local and systemic, of formocresol. Ferric sulphate
Experimental evidence has shown that sufficient formoc-
resol was absorbed systemically from multiple pulpotomy Ferric sulphate is commonly used in dentistry for control
sites in an experimental animal to induce early tissue of bleeding during surgery or for gingival retraction. When
injury in the kidneys and liver.38,39,40 However, it was applied directly to pulp tissue, a ferric ion-protein complex
argued that due to the quantity normally used in man, the is formed which blocks the cut vessels mechanically.
risk is much less and may therefore be negligible. A defi- Although not a fixative, having only bacteriostatic proper-
nite relationship between formocresol pulpotomies in ties, ferric sulphate is used to control haemorrhage by
primary teeth and enamel defects on their permanent suc- gentle intermittent application of a 15.5% solution for up
cessors has been demonstrated,41 but not confirmed in to 15 seconds (Fig. 11.4). A zinc oxide–eugenol base is
other studies.42,43 In addition, carcinogenic and mutagenic then placed to cover the pulp stumps, prior to the coronal
properties have been recognized, which together with restoration.
local and systemic effects, have led to the use of a 20%
(1 : 5) diluted solution.44,45 The International Agency for A better clinical success rate was reported, after 1 year,
Research on Cancer (IARC) classified formaldehyde as a when 15.5% ferric sulphate was compared with 1 : 5
carcinogen in 2004. Case control and cohort studies of diluted formocresol.56 However, the preliminary report
workers exposed to formaldehyde daily have shown an from another study was that there was no difference
association between formaldehyde exposure and nasopha- between the two medicaments.57 Following these results,
ryngeal cancer and leukaemia. This has raised questions the ferric sulphate technique was subjected to further clini-
as to the continuing use of formocresol in children. The cal investigation with a longer follow-up period, and
use of alternative medicaments has been debated within found to perform well.58 Recent systematic reviews have
the literature due to alternative methods being shown to concluded that the treatment outcome with either formo-
be equally successful clinically.46,47,48 Although a recent cresol or ferric sulphate is similar.59,60 The short applica-
evaluation of the research regarding safety of formalde- tion time is a clear advantage when treating children, and
hyde concluded that there was inconsequential risk of hence, ferric sulphate is considered an alternative to
carcinogenesis associated with formaldehyde use in pae- formocresol.
diatric pulp therapy,49 there is continuing unease. There is
a growing movement away from using formocresol and
most paediatric dentists now prefer to use alternative
medicaments. Nevertheless, the clinician should always
consider each case individually and involve parents in the
decision-making process when treatment planning.

Glutaraldehyde

Glutaraldehyde has been investigated as an alternative
fixative to formocresol because of its lower toxicity.50 Glu-
taraldehyde is a larger molecule than formaldehyde, and
as a result diffusion through the tissues is reduced. When
2% unbuffered glutaraldehyde was used, over 96% clinical
success was reported after 42 months.51,52 A 90% clinical
success rate was reported after 1 year, where 2% buffered
glutaraldehyde was applied for 5 minutes in pulpoto-
mies.53 At follow-up after 2 years there was a failure rate
of 18% as a result of internal resorption;54 the authors
concluded that the relatively high failure rate reported in
this study does not justify recommending a 2% buffered
glutaraldehyde solution as a substitute to formocresol.

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Endodontics in primary teeth Chapter | 11 |

Calcium hydroxide greater than 90%. Studies have also compared MTA to
formocresol and calcium hydroxide.67 A small study com-
Although the application of pure calcium hydroxide to the pared the use of formocresol, ferric sulphate, calcium
cut pulp stumps after haemorrhage control was previously hydroxide and MTA in primary molar pulpotomies and
favoured for pulpotomy of primary teeth,61 the work of showed no significant difference in the success of any of
Magnusson62 cast doubt on the use of this material in the medicaments.63 However, internal root resorption,
primary teeth. However, later studies indicated that if a seen with both ferric sulphate and formocresol, was not
carefully controlled technique is used, then calcium observed in the MTA treated teeth.20 MTA is relatively
hydroxide may produce long-term results which are com- expensive when compared with other pulpotomy medica-
parable with those obtained with formocresol.21,22,63 ments which may limit its more widespread use.
Calcium hydroxide in its pure, powder form is a clinically
acceptable alternative when strict selection criteria are Corticosteroids
used.64 The critical factor is the level of inflammation in
the pulp and attempts have been made to assess this objec- Corticosteroid may be used to suppress pulpal inflamma-
tively by measuring prostaglandin levels;65 however, this tion for the short-term purpose of desensitising the
work is still experimental. pulp. Ledermix (Haupt Pharma GmbH, Wolfratshausen,
Germany), a corticosteroid-antibiotic dressing may be
A well-conducted randomized controlled trial compar- useful in treating the inflamed, but not infected pulp,
ing the relative effectiveness of formocresol, ferric sul- when it is too painful to allow pulp tissue removal. Led-
phate, laser and calcium hydroxide reported equally ermix is placed directly over the exposed pulp followed by
successful results with formocresol, ferric sulphate and a temporary dressing. The tooth is then revisited a week
laser. Only calcium hydroxide performed significantly or so later and pulp removal is then carried out. Corticos-
worse and hence, considered less appropriate for pulpoto- teroid compounds should only be used in carefully
mies.66 Other studies have shown that calcium hydroxide selected cases and never as a substitute for proper
does not perform well as a pulpotomy medicament when treatment.
compared with available alternatives.67 This could be due
to the reported high incidence of internal resorption noted Antibiotics
in calcium hydroxide pulpotomies. The rate of such ‘path-
ological’ resorption compared with ‘physiological’ resorp- Recently, the concept of ‘Lesion Sterilization and Tissue
tion should be borne in mind when using this criterion to Repair’ (LSTR) was developed in which a combination of
classify a pulpotomy as a ‘failure’. antibiotics is employed to disinfect the infected root canal
system. A study on primary teeth with infected root canals
Mineral Trioxide Aggregate and periapical lesions in which a mixture of antibiotics
(metronidazole, ciprofloxacin, and minocycline) was
Mineral Trioxide Aggregate (MTA) was originally formu- placed at the orifices of root canals or in the pulp chamber
lated as a root-end filling material in apical surgery.68 It is reported promising results.76 However, research is limited
available in either grey or white forms and is, chemically, and this technique is not recommended at present.
similar to Portland cement (mixture of dicalcium silicate,
tricalcium silicate, tricalcium aluminate, gypsum and tet- Bone morphogenic proteins
racalcium aluminoferrite), but made radiopaque due to
the addition of bismuth oxide.69 It is biocompatible, has Bone morphogenic proteins (BMP) is a family of growth
a high compressive strength, good sealing ability and the factors that was discovered following the observation that
potential to induce the formation of a hard tissue barrier. demineralized bone matrix can stimulate new bone when
The setting time of MTA has been reported to vary from implanted in an ectopic site such as muscle.77 With the
45 to 175 minutes70 Due to this long setting time, the development of molecular biology, these factors were iso-
initial compressive strength is low. Glass ionomer or com- lated and their physiological roles investigated. A number
posite resin can be placed directly over MTA with no of BMP are capable of inducing reparative dentine and
adverse reactions.71,72 It is, therefore, advisable to restore recombinant human BMP have been used experimen-
the tooth immediately with a preformed metal crown or tally.78 These materials would have clear advantages in
a composite resin restoration. Following its successful pulpotomy techniques, producing a biological barrier
application in endodontics for permanent teeth, MTA was without concern regarding toxicity.
suggested as also being suitable for endodontics in primary
teeth. The MTA powder is mixed with sterile water to form Pulpectomy
a paste. This is then placed over the pulp stumps once
haemostasis has been achieved. It has been recommended Non-vital primary teeth may be retained successfully when
as an alternative to formocresol for pulpotomies in this technique is employed but it may be technically dif-
primary teeth73,74,75 and the reported success rates are

203

Harty’s endodontics in clinical practice

Figure 11.5  A buccal draining abscess related to two • resorption at a rate similar to that of the deciduous
carious deciduous molars.
tooth;
ficult to carry out due to the fine ribbon-like canals and
the high incidence of accessory canals. Pulpal necrosis, • antiseptic properties.
alveolar swelling, interradicular or periapical radiolucency
are not contraindications to this treatment modality. Root Resorbable materials based on zinc oxide–eugenol,
canal treatment provides the most satisfactory method of calcium hydroxide and iodoform paste have been used
retaining the restorable primary tooth where infection successfully.79,80,81 Vitapex (Neo Dental, Federal Way, WA,
extends to the radicular pulp and extraction remains the USA), a premixed calcium hydroxide and iodoform paste,
only other option. The whole procedure may be com- has also been recommended as a root canal filling material
pleted in one visit when there is no infection, or over two for primary teeth82 and has been shown to be clinically
visits if infection is present (Fig. 11.5). superior to zinc oxide-eugenol,79 as has another iodoform-
based material (Kri paste).83
Once any initial pain or swelling has been relieved, an
access cavity is prepared under rubber dam isolation. The The chosen filling material should be mixed to a
use of local anaesthesia is recommended as some vital creamy consistency and carried into the canals using a
tissue could still be encountered in the root canal system. pressure syringe, spiral root canal filler, or if mixed to
Any pulp tissue in the root canal system is removed, and a stiffer consistency, packed into the canal with pluggers.
the canals are cleaned with small files (sizes 15 and 20) Various filling techniques including the Lentulo spiral
to within 2  mm of the radiographic apex. Sodium filler and the Jiffy tube pressure syringe have been com-
hypochlorite solution (1%) should be used to irrigate the pared for filling root canals of primary teeth; the Lentulo
canals and achieve chemical dissolution of any remaining spiral was found to perform best.84 After root canal filling,
pulp tissue. An alternative is chlorhexidine (0.2%) but this the pulp chamber should be packed with a suitable
has no tissue solvent properties. The canals are then dried cement, and the tooth restored with a preformed metal
with paper points and filled. If treatment is carried out crown. Teeth that have had a pulpectomy should be fol-
over two visits and if required, the canals are dressed with lowed up clinically and radiologically; if failure occurs,
non-setting calcium hydroxide and a temporary filling. extraction should be considered. Pulpectomy can also be
considered to be an alternative to current pulpotomy tech-
There is no agreed consensus as to the preferred root niques when treating vital primary teeth with carious
canal filling material, but it should have the following exposure.
properties:
LEARNING OUTCOMES
• non-irritant to the periapical tissues and the
After completing this chapter the reader should be able
underlying, developing permanent tooth; to understand and discuss the:

• endodontic challenges of treating the primary

dentition and the patient management issues
associated with the young patient;

• importance and difficulties of correct diagnosis and

its influence on treatment planning;

• factors to consider when deciding whether

endodontic treatment is appropriate or not;

• various endodontic treatment procedures for

primary teeth;

• medicaments used in endodontic treatment of

primary teeth;

• importance of eliminating infection in order

to secure a successful endodontic treatment
outcome.

204

Endodontics in primary teeth Chapter | 11 |

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1904;18:1193–1197. school children. Pediatric Dentistry clinical study of ferric sulfate as a
1981;3:321–324. pulpotomy agent in primary teeth.
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40. Myers DR, Pashley DH, Whitford of Endodontics 1975;1:233– 61. Berk H. Effect of calcium-hydroxide
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Dental Association 1977;94: primary teeth. Journal of 63. Sonmez D, Sari S, Cetinbas T. A
698–700. Pedodontics 1986;10:148–155. comparison of four pulpotomy
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method to detect and quantify trioxide aggregate. Journal of pulp by recombinant human bone
Prostaglandin E2 in pulpal blood Endodontics 2008;34:478–480. morphogenic proteins (BMP)-2
from cariously exposed, vital and -4. Journal of Dental Research
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Endodontic Journal 1999;32: Egilmez T. The evaluation of bond
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controlled trial of mineral trioxide and vitapex for root canal
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et al. The effectiveness of mineral pulpotomy in primary molar teeth. International Journal of Paediatric
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pulpotomies in primary teeth. 81. Cerqueira DF, Mello-Moura AC,
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2008;41:547–555. Mineral trioxide aggregate vs. Cytotoxicity, histopathological,
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68. Torabinejad M, Hong CU, primary molars: a preliminary of an endodontic iodoform-based
McDonald F, Pitt Ford TR. Physical report. Pediatric Dentistry paste used in pediatric dentistry: a
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Long-term evaluation of 82. Kubota K, Golden BE, Penugonda
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trioxide aggregate. Dental Materials formocresol. Pediatric Dentistry literature. Journal of Dentistry for
2005;21:297–303. 2005;27:129–136. Children 1992;58:225–227.

70. Srinivasan V, Waterhouse P, 76. Takushige T, Cruz EV, Asgor Moral 83. Holan G, Fuks AB. A comparison
Whitworth J. Mineral trioxide A, Hoshino E. Endodontic of pulpectomies using ZOE and
aggregate in paediatric dentistry. treatment of primary teeth using a KRI paste in primary molars: a
International Journal of Paediatric combination of antibacterial drugs. retrospective study. Pediatric
Dentistry 2008;19:34–47. International Endodontic Journal Dentistry 1993;15:403–407.
2004;37:132–138.
71. Ballal S, Venkateshbabu N, 84. Aylard SR, Johnson R. Assessment
Nandini S, Kandaswamy D. An in 77. Urist M. Bone formation by of filling techniques for primary
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glass ionomer cement when
layered over partially set mineral 78. Nakashima M. Induction of dentin
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Chapter 12 

Endodontic aspects of traumatic injuries

H.E. Pitt Ford

CHAPTER CONTENTS Root canal retreatment 225
Tooth discolouration 225
Summary 209 Orthodontic treatment 226
Introduction 209 Learning outcomes 226
History, examination and immediate References 226
management 210
Types of injury 211 SUMMARY
Effects of trauma on the dental tissues 212
Management of primary teeth 212 Correct diagnosis and treatment planning are fundamen-
212 tal to successful endodontic management of traumatized
Fractures 212 teeth. The preservation of pulpal vitality in a young tooth
Luxation injuries 213 is very important for further development and maturation,
Tooth discolouration 213 allowing the tooth to attain structural strength, otherwise
Management of permanent teeth 213 it is very liable to fracture. The elimination of infection
Fractures 217 during root canal treatment is critical to achieving a suc-
Luxation injuries 220 cessful outcome. The introduction of Cone Beam Com-
Root canal treatment of immature teeth 221 puted Tomography (CBCT) is a valuable new develop-
Avoidance of cervical root fracture 222 ment in the diagnosis of complex traumatic injuries. The
Surgical treatment of immature teeth efficiency of root canal treatment of non-vital immature
Revascularization treatment of immature 222 teeth has greatly improved with the more widespread use
teeth of Mineral Trioxide Aggregate. Better illumination and
Regenerative treatment of immature 223 magnification through the use of an operating microscope
teeth facilitates the management of complex cases, which may
Auto-transplantation of an immature 223 be best referred to a specialist centre. Clinicians should
premolar into the incisor space 223 always bear in mind the possibility of non-accidental
Complications 223 injury in cases of trauma.
External inflammatory root resorption
Cervical external inflammatory root 224 INTRODUCTION
resorption 224
External replacement root resorption 225 This chapter is principally concerned with the endodontic
Barrier formation coronal to the apex 225 aspects of traumatic injuries of the teeth, and does not
Previous injury
209
© 2009 Elsevier Ltd, Inc, BV
DOI: 10.1016/B978-0-7020-3156-4.00015-2

Harty’s endodontics in clinical practice

attempt to cover dental traumatology comprehensively. medical practitioner where appropriate.5 There is further
For this, reference should be made to a textbook on dental coverage on this subject in Chapter 2.
traumatology or to current guidelines.1,2,3 Since most
general practitioners see only a small number of patients The clinical examination should include assessment of
with traumatic dental injuries, it may be appropriate to the soft tissues and facial skeleton. Disturbances to the
refer the more complex injuries to a colleague with special- occlusion are investigated as these may indicate jaw frac-
ist experience. ture or condylar displacement. Any soft tissue injury is
noted and the possible presence of a foreign body consid-
When a tooth has been damaged through trauma, a ered; radiographic examination may be necessary to locate
good history and thorough examination are essential to this. Injuries to the oral mucosa are investigated, especially
ensure a correct diagnosis and the best treatment outcome. bleeding from the gingival sulcus; lacerations may occur
The status of the pulp of all involved teeth must be with displaced teeth; bleeding from a non-lacerated gingi-
assessed, and their vitality maintained wherever possible. val margin may indicate periodontal damage. The probing
Many injured teeth are immature, and their development depths of the gingival sulci are recorded. It should always
and maturation depend on maintaining pulp vitality. It be remembered that the effect of an injury may not be
should be borne in mind that vital teeth may not respond confined to the visibly affected teeth, and adjacent, appar-
to sensitivity testing immediately after an accident. Main- ently unaffected teeth should always be included in the
taining dental pulp vitality is covered in Chapter 5. examination and investigations. Infractions, fractures,
pulpal exposures, mobility or displacement are noted
HISTORY, EXAMINATION AND along with any colour changes. A dark discolouration
IMMEDIATE MANAGEMENT immediately after the injury indicates haemorrhage within
the pulp space. There may be potential for repair and,
A dental injury should always be treated as an emergency. therefore, this is not an indication for root canal treat-
Management of any severe bleeding or respiratory prob- ment. If, however, the tooth becomes dark some months
lems takes priority. Any period of unconsciousness, after the injury this usually indicates pulp necrosis. Yellow
amnesia, headache, nausea or vomiting may indicate cer- discolouration some time after the injury is associated
ebral involvement, and the patient should be referred with pulp calcification and is not an indication for root
immediately for medical examination and appropriate canal treatment, even if there is no response to sensitivity
care.1,4 It is important to give a full explanation of the testing.6 Lost pieces of fractured teeth should be accounted
extent of the injury and the prognosis to anxious parents. for; in case they are embedded in soft tissue, or have been
Inconsistencies between the history and the injuries sus- swallowed or inhaled. Thermal sensitivity of the teeth may
tained, particularly if accompanied by late presentation, be a consequence of exposed dentine or pulp. Mobility
should alert the clinician to the possibility of non-acciden- and percussion testing should be carried out as they may
tal injury.1 indicate damage to the supporting tissues.

A full account of when, where, and how the injury Response to pulp sensitivity testing should be recorded.
occurred must be recorded. The circumstances of the acci- Some injured teeth may have the potential to recover but
dent may have legal implications and a photograph may may not respond for up to 2 years after trauma;7the results
be especially useful. The time interval between injury and of sensitivity tests will provide a baseline for later com-
presentation can influence the choice of treatment, and parison. A negative response to sensitivity testing should
may be critical to the success of replantation of avulsed not, therefore, be taken as an indication for root canal
teeth. The place where the injury happened may suggest treatment. Blood flow in severely luxated teeth has been
possible contamination of open wounds and the need for shown some time ahead of their pulps responding to elec-
tetanus prophylaxis. The way the injury occurred may give tric pulp testing.7,8,9 In assessing vitality of luxated teeth
some indication of the type and the extent. Any previous it is not unusual for the findings to be contradictory.61
injury or treatment should be recorded. The medical Radiographic examination of permanent teeth should
history must be reviewed as this may influence treatment include a paralleling technique periapical film of each
planning, for example, if the patient suffers from an affected tooth using a film holder to standardize projec-
immunological or blood disorder. The current National tions for later comparison. For luxation injuries a further
Institute for Health and Clinical Excellence (NICE) guide- film, with the tube rotated horizontally, is often helpful.11
lines state that antibiotic prophylaxis against infective If a root fracture is suspected in the maxillary incisor
endocarditis is not recommended for patients undergoing region an occlusal radiograph should be taken. If an
dental procedures; however, it is essential to keep up to immature tooth has been non-vital for some time, its
date with current guidelines and to liaise with the patient’s development will have been arrested, leaving the pulp
space larger than would be expected. For primary teeth an
occlusal film alone is usually sufficient. Cone Beam Com-
puted Tomography (CBCT) is a very valuable new devel-

210

Endodontic aspects of traumatic injuries Chapter | 12 |

AB

Figure 12.1  Maxillary left central incisor. (A) Radiograph showing the horizontal root fracture. (B) Cone beam CT scanning
gives a more comprehensive three-dimensional view of the fracture (reproduced courtesy of S Patel).

opment in the diagnosis of traumatic injuries; the covered in more detail later. If the patient is very upset, it
three-dimensional picture gives much more information may be better to delay non-urgent treatment until a sub-
than a standard radiograph12–16 (Fig 12.1). sequent visit. In the case of a traumatically exposed pulp,
inflammation has been shown not to extend beyond
Following a thorough clinical and radiographic exami- 3–4 mm after several days.18 Unless unavoidable, it is most
nation, a diagnosis is made for each injured tooth. The important not to remove the pulp of an immature tooth
importance of this cannot be overstated. The outcome of which has the potential for further maturation.
treatment is dependent on a correct diagnosis as inappro-
priate treatment may readily be initiated at this stage.1,17 TYPES OF INJURY
The prognosis should be considered and the value, or
otherwise, of endodontic treatment determined. Newer Trauma may cause the following damage to the teeth:
treatment methods, such as the introduction of Mineral
Trioxide Aggregate (MTA) (ProRoot MTA, Dentsply, Wey- • infraction of enamel
bridge, Surrey, UK) have resulted in a reduced number of • fracture of enamel
treatment visits, less stressful and demanding of patients • fracture of enamel and dentine
who have sustained dental injury. Also, methods of • fracture of enamel and dentine with pulp exposure
strengthening the cervical region of immature teeth reduce • crown-root fracture involving enamel, dentine,
the risk of loss through fracture (see later). A tooth is the
best space maintainer and, provided it is free of infection, cementum and pulp
its retention preserves alveolar bone for later restoration.
• intra-alveolar root fracture
Soft tissue injuries should be cleaned and sutured if • concussion
necessary, and any tooth fragments embedded in the lips • subluxation
removed. Exposed dentine is covered and pulp exposures • extrusive luxation
treated; displaced teeth are repositioned and splinted • lateral luxation
when appropriate. If a permanent tooth has been avulsed, • intrusive luxation
the socket is irrigated with saline to remove blood clot, • avulsion.
and the tooth replanted and splinted. These injuries are

211

Harty’s endodontics in clinical practice

Sudden contact of upper and lower teeth caused by, for
example, a blow to the mandible can result in damage to
posterior teeth. These injuries are rare but can result in a
range of damage, from minimal loss of hard tissue to verti-
cal crown-root fracture or avulsion.

EFFECTS OF TRAUMA ON
THE DENTAL TISSUES

Many traumatized teeth are immature. These teeth have Figure 12.2  Primary maxillary central incisors that have
large pulp spaces and short, wide dentinal tubules. Infec- suffered a traumatic injury. The maxillary left incisor has
tion may, therefore, readily spread to the pulp if the crown responded with calcification of the pulp space, while the
is fractured. This may lead to loss of vitality due to sever- right incisor has developed an abscess.
ance or crushing of the apical vessels during luxation inju-
ries. The pulp of an avulsed tooth may also become infected primary tooth should not be left untreated as the
infected via the apex, if contaminated. Teeth depend on a infection may cause damage to the permanent successor
vital pulp in order to develop their potential maturity and (Fig. 12.2).
strength. A tooth that loses its vitality while immature is
always prone to fracture, especially in the cervical region Intra-alveolar root fracture
of the root.19
This is less common in primary teeth than in permanent
The cementum on the root surface may be damaged by teeth. Active intervention is rarely required. If the coronal
luxation injuries; the natural repair mechanism involves fragment is very loose and at risk of being inhaled or
limited surface resorption. However, where there is exten- grossly displaced, or if pulp necrosis and infection develop,
sive damage to the cementum, ankylosis associated with extraction is usually indicated; however, the apical frag-
replacement resorption is a frequent complication. If ment is normally left in situ to resorb naturally and to
infection from the pulp complicates damage to cemen- avoid surgical damage to the developing permanent
tum, then external inflammatory root resorption may be successor.
very rapid, particularly in immature teeth.1,2
Luxation injuries
MANAGEMENT OF PRIMARY TEETH
In general, a conservative approach to management is
When a primary tooth is injured, a major consideration is adopted with primary teeth. Laterally luxated primary
avoidance of damage to the successional tooth. This may teeth are frequently repositioned naturally in time by
occur either mechanically at the time of injury, during occlusal and muscular forces. If a laterally luxated tooth
treatment, or as a result of infection.1,20 Young children interferes with the occlusion, the injury is mild and there
may not be very cooperative, particularly after a traumatic is no risk to the permanent successor, it may be carefully
injury when the soft tissues are sore, swollen and bruised, repositioned.1,22 If the root apex is directed palatally
therefore, immediate treatment may need to be limited. towards the developing permanent tooth then it should
be extracted atraumatically. If a tooth is very mobile and
Fractures in danger of inhalation, or if occlusal interference is too
great, it should be extracted. Intruded teeth will usually
Crown fractures re-erupt albeit sometimes over several months. If the pulp
becomes non-vital and infected, root canal treatment may
Enamel fractures should be smoothed, while fractures be considered (see Ch. 11). Replantation of avulsed
into dentine should be covered. If the pulp has been primary teeth is not normally carried out because of the
exposed and if there is sufficient cooperation, a partial potential risk of direct physical damage to the developing
pulpotomy and restoration may be carried out with a view
to preserving pulp vitality; this does not need to be at the
emergency visit.18,21 Otherwise, extraction of the tooth
may be indicated. The technique of pulpotomy is covered
in the section on permanent teeth. Root canal treatment
of primary teeth has been covered in Chapter 11. An

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Endodontic aspects of traumatic injuries Chapter | 12 |

permanent tooth, or damage from later infection of the therefore, result in damage to the pulp. Fractures involving
pulp of the primary tooth. dentine open up numerous dentinal tubules. If left
untreated, microbial plaque will grow on the exposed
Tooth discolouration surface and cause pulpal inflammation, which may lead
to pulp necrosis. The early placement of a restoration
Pulp damage is a frequent complication of injuries, and prevents permanent pulp damage and relieves sensitivity.
as a result primary teeth may discolour. Immediate discol- The use of etched and bonded composite resin restores the
ouration indicates bleeding in the pulp and the possibility appearance and does not hinder subsequent monitoring
of repair. Later darkening of the tooth signifies pulp necro- of pulp vitality (Fig. 12.3). This has been shown to seal
sis and if there is associated infection, root canal treatment more effectively than conventional glass ionomer
or extraction is indicated. Later yellow discolouration indi- cement.25 Restoration of the contour of the tooth may be
cates pulp canal obliteration and no intervention is left until a later visit. A fractured fragment may be success-
required (Fig. 12.2). fully reattached with composite resin retained by etched
enamel. The likelihood of pulp canal obliteration or pulp
MANAGEMENT OF necrosis occurring is low following fractures involving
PERMANENT TEETH dentine, provided the dentine tubules are effectively
covered.1,23 The chance of pulp damage is increased if there
is associated luxation of the tooth.24,26

Fractures Fracture of enamel and dentine
with pulp exposure
Infractions and fracture of enamel
Immature teeth
Infraction of enamel rarely requires operative treatment,
but the pulpal status should be monitored. Infection may If this type of injury occurs in a young patient
very rarely enter the pulp through enamel infractions. whose permanent tooth is immature, then treatment is
There is no effective treatment to avoid this. Fractures of directed at maintaining pulp vitality to allow continued
enamel may be either smoothed or repaired with compos- tooth maturation; this considerably improves the long-
ite resin. The likelihood of pulp canal obliteration or pulp term prognosis of the tooth by reducing the risk of subse-
necrosis occurring is low for both enamel infractions and quent root fracture.19 Permanent incisor teeth have
enamel fractures.23 The chance of pulp damage is increased been shown to reach maturity at the age of about 13 years.
if there is associated luxation of the tooth.24 The pulp can usually be treated conservatively as it has
a good blood supply and rarely becomes necrotic.27,28
Fracture of enamel and dentine Partial pulpotomy is the treatment of choice.18,27,29,30,31 The
advantages of partial pulpotomy over pulp capping
In children, trauma to anterior teeth commonly affects are that inflamed pulp tissue and adjacent infected dentine
sound teeth, which frequently have large pulps and wide are removed, and that the pulp dressing is placed in a
dentinal tubules. Any injury that exposes dentine can, cavity where it can be covered by a protective base. If the

AB
Figure 12.3  (A) Fractured incisal edges of maxillary central incisors exposing dentine. (B) Restoration of incisal edges using
composite resin retained by etched enamel.

213

Harty’s endodontics in clinical practice

AB

Figure 12.4  (A) Maxillary right central incisor with a fracture involving the pulp. (B) After placement of medicament in the
partial pulpotomy preparation.

restoration is lost, the cavity dressing should not be the hard tissue barrier is usually porous.18 This treatment
displaced. has a high success rate; the pulp may be expected to
remain vital and healthy.18,27,29 There is no need for root
Local anaesthesia is necessary to carry out a pulpotomy. canal treatment subsequent to pulpotomy, unless necrosis
The tooth is isolated with rubber dam to exclude salivary and infection develop.32
contamination; retention of rubber dam on an immature
tooth is facilitated by a suitable clamp (e.g. Ash EW, Dent- Mature teeth
sply). A small cavity approximately 2 × 2 mm is cut in the
fractured dentine surface at the exposure site, with the Where crown fracture of a mature tooth involves the pulp,
periphery of the cavity floor in dentine (Fig. 12.4). Pulp conservative treatment by partial pulpotomy should still
removal is usually confined to the superficial 2 mm since be considered as the first treatment option. However,
infection does not normally extend beyond this level.18 where the entire clinical crown has been lost, pulpal extir-
The pulp is best removed with a bur in the turbine hand- pation, root canal filling and construction of a post-
piece using copious water spray; this causes less damage retained crown is usually indicated.
than a bur at slow-speed or an excavator.29,30,32 Haemor-
rhage is arrested using a cotton pellet soaked in saline and Crown-root fracture involving enamel,
the wound is covered with MTA.31,33,34,35,36 Over this is dentine, cementum and pulp
placed a layer of resin-modified glass ionomer cement,
before restoring the tooth with composite resin. Should In this type of extensive tooth fracture, the coronal frag-
the composite resin be lost the restoration within the ment is usually retained by a limited amount of periodon-
cavity should remain intact. MTA has been shown to give tal ligament. These teeth may have a poor prognosis,
better results than calcium hydroxide in this situation.31,33 especially if the fracture line is a long way subgingival on
Alternatively, the cavity may be restored with a calcium the palatal aspect. When the patient first presents, the
hydroxide base (either a slurry which is subsequently com- coronal fragment is often loose and painful to bite on. It
pressed and dried with cotton wool or a hard setting base is usually necessary to give local anaesthesia to allow
material) and a resin-modified zinc oxide-eugenol cement removal of the fragment and to assess the extent of the
(IRM, Dentsply) followed by glass ionomer cement. fracture. If time does not allow this, the fragment may be
bonded temporarily to the tooth to minimize discomfort.
The coronal contour should then be restored with Where the fracture does not extend far subgingivally, it is
etched-retained composite resin. A hard tissue barrier often possible to restore the tooth without crown length-
should form beneath the dressing.29,30,34,35 The tooth ening. Otherwise periodontal surgery to expose the margin
should be reviewed after six months, and then at least of the fracture, or orthodontic extrusion, will need to be
annually for several years, to ensure continued pulp vital- considered. In an immature permanent tooth with an
ity by regular pulp testing, and continued root develop- exposed pulp, where the fracture does not extend far
ment by examination of radiographs. Should the subgingivally, pulpotomy should be carried out (as
restoration fail, it must be replaced immediately in order
to prevent infection of the pulp via the pulpotomy site, as

214

Endodontic aspects of traumatic injuries Chapter | 12 |

described above). Where loss of the root is more extensive, otherwise, elective decoronation may be used to preserve
the tooth will be difficult to restore and is likely to have a the alveolar ridge.
poor long-term prognosis. While its loss will be planned
for, in the longer term, it may be possible to carry out Intra-alveolar root fracture
a pulpotomy, restoring the supragingival contour with
composite resin and retain the tooth while the dentition Intra-alveolar root fractures are relatively uncommon,
continues to develop. and fortunately, often occur without the complication
of microbial contamination from the mouth. The coronal
In a mature tooth where the fracture is superficial, fragment may be mobile with the fulcrum coronal to
pulpotomy may still be the first line of treatment, or it the apex, and may be extrusively or laterally luxated. The
may be more appropriate to carry out root canal treatment tooth should be examined carefully for any periodontal
and restore the tooth with a post-retained crown. If the injury whereby the gingival sulcus communicates with the
fracture is deeper, it will be difficult to isolate the tooth fracture; this substantially reduces the prognosis. Diagno-
for root canal treatment, and orthodontic extrusion of the sis of intra-alveolar root fracture is made by radiological
root followed by crown lengthening will need to be con- examination with two films, taken at different vertical
sidered before restoration by a post-retained crown.1 angles. Root fractures are more frequently observed on
When the fracture is very deep, there may be insufficient an occlusal film than a film taken with a paralleling tech-
root remaining to support a restoration even after ortho- nique (Fig. 12.5). CBCT has greatly contributed to diag-
dontic extrusion; such teeth are also more likely to fail nosis of complex fractures, as it gives a three-dimensional
subsequently. Where the prognosis is very poor, extraction view.14,15,16
of the remaining root should be considered if it is infected;

AB
Figure 12.5  Maxillary left central incisor. (A) Part of an occlusal radiograph more easily demonstrates an intra-alveolar root
fracture (arrowed) than (B) a paralleling-technique radiograph on which the fracture is more difficult to see.

215

Harty’s endodontics in clinical practice

The apical fragment almost without exception remains between splinting method, duration and healing.38 No
vital, and does not require treatment. This is, therefore, displacement of the coronal fragment and preserved vital-
in effect a luxation injury of the coronal fragment. If ity of the pulp are highly indicative of fracture healing.37,38,39
there is no mobility or displacement, immediate treatment A splint should allow physiological movement to avoid
is not required and the fractured root should heal with ankylosis. The patient is advised to use a chlorhexidine
hard tissue formation; the pulp is likely to remain mouthwash to maintain oral hygiene, and the tooth
vital. Teeth that have fractures remote from the gingival reviewed at the time of intended splint removal. Pulp
sulcus have the best long-term prognosis (Fig. 12.5). If the sensitivity is checked. Where there is no response, the
fracture is close to the neck of the tooth, the prognosis will tooth should be reviewed clinically at 3-monthly intervals.
be poorer, but extraction need not be indicated, unless Where no vital response is obtained, provided there is no
there is a communication between the gingival sulcus and tenderness to palpation, nor a sinus tract, pulp testing
the fracture line. Teeth with a transverse fracture have a should be carried out at 3 and then 6-monthly intervals
poorer long-term prognosis than those with an oblique either until a response occurs, or evidence of pulp necrosis
fracture because of the risk of future displacement37,38 appears. Radiographic review should normally be restricted
(Fig. 12.6). to once or twice yearly unless there is a risk of external
inflammatory root resorption.
If the tooth is displaced or mobile, immediate treatment
consists of repositioning the coronal fragment and The most favourable response is uniting of the two frag-
splinting if it is very mobile, typically, for approximately ments by hard tissue laid down both in the root canal and
4 weeks. Recent work has failed to show a correlation on the root surface. A less favourable but still satisfactory
outcome is continued pulp vitality in the coronal fragment
Figure 12.6  Radiograph of a maxillary right central incisor but no union of the fragments. The sharp edges at the
with a horizontal root fracture close to the gingival margin. fracture line become rounded by remodelling, and con-
The pulp responded to electric pulp testing one year after nective tissue and/or bone lie between the fragments; the
trauma; however, the long-term prognosis is poor. space between the fragments may increase with continued
alveolar growth in younger patients. Often the pulp in the
coronal fragment calcifies and radiologically shows an
obliterated pulp space; the pulp may not respond to sen-
sitivity testing.40,41 Pulp canal obliteration itself is not an
indication for root canal treatment.1,42

Pulp necrosis occurs in approximately 20% of intra-
alveolar root fractured teeth and is associated with initial
coronal displacement, lack of pulp sensitivity after the
accident, coronal position of the root fracture, a commu-
nication with the gingival sulcus, maturity of the root and
coronal fracture.37,38,39,41 Pulp necrosis is invariably con-
fined to the coronal fragment.1 As well as the loss of
response to thermal and electrical stimuli, there is fre-
quently radiolucency in the bone around the tooth at the
fracture line (Fig. 12.7). Root canal treatment should be
carried out in the coronal fragment alone unless there is
definite evidence to implicate involvement of the apical
fragment. Following cleaning of the canal in the coronal
fragment, a well-packed dressing of calcium hydroxide
may be placed, if required, to assist disinfection of the
canal; MTA is subsequently placed in the first 3–4 mm at
the fracture line, followed, if desired, by back filling with
gutta-percha (see section on root filling of immature teeth
for method)35 (Fig. 12.7). This treatment has a high success
rate.43 If there is an inadequate stop at the apical end of
the coronal fragment, the first 1–2  mm may be packed
with calcium hydroxide, or a sterile resorbable material
(e.g. Surgicel, Johnson and Johnson Medical Ltd., Gar-
grave, N. Yorks, UK) may be inserted to limit extrusion of
MTA at the fracture site. It is not normally practical to
attempt to root treat both fragments. If the apical fragment
is non-vital surgical removal is indicated.

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Endodontic aspects of traumatic injuries Chapter | 12 |

Concussion

This is an injury to the supporting tissues without loosen-
ing or displacement of the tooth. Lasting pulp damage
is rare, especially in an immature permanent tooth,
although the tooth may not respond to sensitivity testing
for some months.

AB Subluxation

The tooth is loosened in its socket but not displaced. With
subluxation there is unlikely to be severance of the blood
vessels supplying the pulp, giving a good possibility of
pulp survival. Pulp survival rate is 90% for immature teeth
and 75% for mature teeth.11 It is essential to allow the pulp
time for recovery before deciding to remove it.

Extrusive luxation

If this is severe the pulpal vessels and nerves are usually
severed. In an immature tooth that is repositioned soon
after injury, revascularization, followed by obliteration of
the pulp space, is the likely outcome; in a mature tooth
pulp necrosis is more common.11 External inflammatory
root resorption may occur following pulp necrosis.

CD Lateral luxation

Figure 12.7  (A) The maxillary left central incisor has a root The tooth is displaced laterally and the apex may be
fracture in the mid-third and has been splinted; there is a locked into bone. This can be diagnosed by percussion,
radiolucency at the fracture line (arrowed). (B) The root canal when the tooth gives a high ringing tone. This crushing
of the coronal fragment has been disinfected and filled with injury causes damage to the supporting structures. The
MTA to the fracture line. (C) The neck of the tooth has been labial plate of bone may also be fractured. Pulpal healing
filled with etched and bonded composite resin. (D) One year may be expected in 70% of immature teeth11 (Fig. 12.8).
later, healing has taken place and further calcification has Revascularization will take some weeks but return of func-
occurred in the apical fragment indicating that it is still vital. tioning nerve fibres may take a year or more;45 therefore,
root canal treatment should not be undertaken unless
Luxation injuries there is positive evidence of pulpal infection. In mature
teeth that have suffered a severe luxation injury pulpal
A luxation injury is characterized by damage to the sup- healing is unlikely, and therefore, root canal treatment is
porting tissues of the tooth and the tooth may be dis- indicated, except in cases where follow-up can be assured
placed. There may be interruption of the vessels and to observe for possible recovery. Damage to the support-
nerves at the apex. The prognosis for pulp recovery is ing structures makes both inflammatory and replacement
reduced if there is a concomitant crown fracture as this is external root resorption frequent complications of lateral
a possible route for entry of microbes. Luxation injuries luxation.11
are the most common type of dental injury.44
A laterally luxated tooth may need to be disimpacted
from its new position, under local anaesthesia if necessary,
to allow correct repositioning. If the apex is displaced labi-
ally, repositioning is most readily achieved from behind
the patient, by pressing with the thumb on the impacted
apex. The tooth may be splinted with a flexible splint for
2–3 weeks (Fig. 12.9). The patient is recommended to use
a chlorhexidine mouthwash during the early stages of
healing. Radiographs are taken at one month to check for
signs of disease, especially external inflammatory root
resorption. If there are signs of this, the pulp should be

217

Harty’s endodontics in clinical practice

AB
Figure 12.8  (A) The immature maxillary right central incisor was luxated. (B) One year later the root has continued to form.

response in the early period after luxation injury. Concur-
rent with return of sensitivity, there may be evidence of
pulp canal obliteration (Fig. 12.10), which is very common
in laterally luxated teeth.46 This causes a yellowish coronal
discolouration and the tooth may cease to respond to
sensitivity testing but it is not an indication for root canal
treatment. In about 4% of luxated teeth periapical radiolu-
cency, together with discolouration and absence of sensi-
tivity, is a temporary phenomenon and disappears as
healing progresses. This is known as transient apical
breakdown.47

Figure 12.9  Emergency treatment after a traumatic injury. Intrusive luxation
The maxillary right central incisor was avulsed and lost. The
maxillary left central incisor was luxated and has been This is a severe injury; the tooth is forced into its socket,
repositioned and splinted. so crushing the supporting structures and the blood vessels
and nerve fibres that supply the pulp. The tooth is likely
removed promptly and the pulp space disinfected. Root to be wedged in the supporting bone, therefore displaying
canal treatment should then be carried out (see later). If a lack of mobility and a ringing note on percussion. Radio-
no signs of disease are observed, the patient is reviewed graphs will show obliteration of the periodontal ligament
again after 2, 3, 6 months and 1 year. Pulp sensitivity space. Many immature teeth will re-erupt spontaneously,
is assessed at each period using thermal and electric but if there is no evidence of this after 3 weeks, rapid
tests; electric pulp testing often does not produce a orthodontic repositioning should be undertaken. Access
to the clinical crown must be available for endodontic
treatment should this become necessary. Severe intrusions
may require surgical repositioning, taking great care

218

Endodontic aspects of traumatic injuries Chapter | 12 |

Figure 12.10  Both maxillary central incisors have suffered Avulsion
luxation injuries and have responded with calcification of the
pulp spaces. The tooth is completely displaced from its socket,
and should be replaced as soon as possible, preferably at
not to damage the cementum in the cervical area.3 Pulp the site of the accident. Immature avulsed teeth, which
necrosis is a very frequent complication of intrusion; 60% have been replanted immediately or correctly stored until
of immature teeth become non-vital.11 Immature teeth emergency treatment can be obtained, have a reasonable
should, therefore, be observed for signs of pulp vitality prognosis for pulp revascularization and periodontal
returning or complications developing. The regime for healing; mature teeth do not revascularize.1 Both external
reviewing intrusions is similar to that for other luxations. inflammatory and replacement resorption are frequent
If evidence of pulp necrosis or infection appears, root complications.48,49,50
canal treatment should be undertaken (see below). Mature
teeth do not re-erupt and almost without exception The avulsed tooth needs careful handling while it is out
become non-vital; endodontic treatment consists of pulp of the mouth to prevent damage to the periodontal liga-
extirpation, disinfection of the pulp space, dressing with ment. It should not be allowed to dry out, and if necessary
calcium hydroxide for a short period and subsequent root is best kept in cold milk. The patient should be taken
canal filling. immediately to an experienced practitioner, who should
decide whether replantation of the tooth is appropriate.2
Radiographs should be taken frequently to check for The medical history must also be considered as to whether
the presence of external inflammatory root resorption. replantation is appropriate, and whether any special pre-
Another complication of intrusion is a high incidence of cautions may be required. The tetanus status should be
replacement resorption,11 as a result of damage to the checked if the accident took place outdoors. The tooth is
cementum. This can be diagnosed by percussion and radi- examined, without touching the root to avoid damage to
ologically. Intrusion is a severe injury, which may be best the periodontal ligament, and dirt rinsed off with saline;
referred for specialist care. under no circumstances should it be scrubbed or severe
periodontal ligament damage will occur. It is helpful to
note the length of the tooth for future endodontic treat-
ment. It may be necessary to take a radiograph of the
socket to check that no tooth fragment remains. Local
anaesthesia may not always be needed; the socket is
syringed with saline to remove any clot, and the tooth
gently repositioned into its socket; the position is then
confirmed radiographically. The tooth is splinted for 7–10
days, using a flexible splint. For optimal healing it is essen-
tial to avoid infection, therefore, in the days following
replantation the patient should use a chlorhexidine
mouthwash to maintain oral hygiene. Current guidelines
also recommend the administration of systemic antibiot-
ics for the avulsed tooth.2 Tetracycline is the first choice,
doxycycline twice a day for 7 days at appropriate dose for
the patient’s age and weight.2 However, the risk of discol-
ouration of permanent teeth must be considered before
systemic administration of tetracycline; it is not recom-
mended for patients under 12 years of age. Phenoxyme-
thyl penicillin (Pen V) may be used as an alternative to
tetracycline provided the patient is not allergic to it.

With an immature tooth with an open apex, there is a
good chance of pulp revascularization, so the pulp should
not be electively removed; revascularization will allow
root formation and maturation to continue, and reduce
the risk of subsequent root fracture.1,19 However, there is
a risk that infection present on the root surface or on the
apical surface of the pulp at the time of replantation may
initiate, or perpetuate, inflammatory resorption, which
can rapidly destroy the thin wall of the immature root. If
this or any other positive sign of infection does occur, the

219

Harty’s endodontics in clinical practice

pulp space should be cleaned and disinfected, and root or very crowded a split dam technique may be used, with
canal treatment undertaken (see below). Otherwise, a caulking agent (OraSeal, Ultradent Products, South
regular clinical and radiological reviews should be under- Jordan, UT, USA). Occasionally, in the early stages of
taken at approximately 1, 2, 3, 6 months and 1 year; the treatment, if the child is exceptionally anxious, local
patient should be asked to return immediately should any anaesthesia and a clamp may be avoided and an alterna-
problems develop. tive rubber dam used (Dry Dam, Directa AB, Upplands
Väsby, Sweden). However, access may be very limited for
With mature teeth the chances of pulp revascularization endodontics and leakage more difficult to control. It is
are so low that the necrotic pulp should be extirpated essential to appreciate that avoiding local anaesthesia and
through a conventional access cavity prior to removal of then the child experiencing pain because of residual vital
the splint. The cleaned and shaped root canal is, initially, pulp may make future treatment very difficult if not
filled with a dressing of calcium hydroxide prior to root impossible; therefore, there is no substitute for adequate
canal filling with gutta-percha. There appears to be no anaesthesia and proper tooth isolation for successful
benefit in leaving calcium hydroxide in the tooth for a endodontics. The access cavity on the palatal surface of the
prolonged period.51,52 In addition, calcium hydroxide crown should be sufficiently large, and sufficiently incis-
should not be inserted within one week of injury, to allow ally placed, to allow adequate access to the wide root
periodontal healing to take place at the apex. canal; care must be taken to remove all remnants of pulp
tissue from the pulp horns, or discolouration of the crown
ROOT CANAL TREATMENT OF may ensue. Since both sodium hypochlorite and calcium
IMMATURE TEETH hydroxide dissolve organic matter it is not strictly neces-
sary to have straight-line access to the whole root canal at
The teeth most commonly injured are the incisors. The the expense of tooth tissue conservation. Indeed, to
apices of these teeth are not normally closed until about attempt this would often be to weaken the neck of the
the age of 13 years; although in a two-dimensional radio- tooth excessively. The cervical constriction apical to the
graph they may appear closed much earlier than this. It is cingulum should be reduced.61 Instrumentation should be
necessary to produce an apical barrier against which a root carried out to 1–2  mm short of the radiographic apex,
filling can be packed. This has, traditionally, been achieved unless necrotic tissue is encountered at this level, when
by disinfection of the root canal space and repeated dress- instruments should be taken further. The length of the
ing with calcium hydroxide until a biological barrier was root canal is estimated by taking a radiograph with a file
achieved. This had the disadvantages of prolonged treat- of known length in place. If the canal is very wide it may
ment for a usually anxious child, risk of root fracture due be helpful to wedge the file in place with a pledget of
to dentine desiccation with prolonged contact with cotton wool.
calcium hydroxide and risk of reinfection due to loss or
leakage of temporary fillings.52,53 More recently, MTA has Excessive filing of the root canal walls must be avoided
been used with success to produce an immediate hard as the canal walls are already thin; instead the pulp space
matrix barrier.33,35,36,53–59 It is necessary first to disinfect the should be cleaned by copious irrigation with sodium
canal. Some operators then dress with calcium hydroxide hypochlorite. The irrigation needle should be pre-meas-
for one week or slightly longer,56 while others rely on irrig- ured, and the irrigant delivered with gentle pressure using
ants to disinfect the canal and immediately place a plug the forefinger to depress the plunger of the syringe, to
of MTA at the apex.57 When set, this acts as a mechanical prevent forcing sodium hypochlorite through the apex.
barrier; hard tissue will eventually form against the After thorough cleaning, a stiff paste of calcium hydroxide,
MTA.35,60 The elimination of infection from the root canal if used, is packed into the canal with root canal pluggers.62
space prior to filling is essential; the canal must be clean Calcium hydroxide is alkaline and has an antimicrobial
and dry. Sometimes a radiolucent area may not resolve effect, and thus allows healing to take place. The quality
immediately. If it persists, this may indicate either a long- of the calcium hydroxide filling may be checked radiologi-
standing infection outside the tooth which requires cally before closure of the access cavity with an effective
surgery, or an undetected, possibly vertical, root fracture. temporary filling (e.g. IRM, Dentsply). The tooth should
A small radiolucency may also remain representing be reviewed and if symptom-free, the calcium hydroxide
scar tissue. is removed, the canal irrigated and dried. MTA can then
be inserted into the apical 3–4  mm using pre-measured
Local anaesthesia is given so that a rubber dam clamp root canal pluggers (Fig 12.11). Some operators use ultra-
can be placed securely on the tooth and in case the sound, transmitted by holding an ultrasonic tip in contact
pulp is still partially vital. Palatal local anaesthesia may with the root canal plugger, to better condense the MTA.63
also be needed, both for clamp application and if vital A check radiograph is taken and revision undertaken if
tissue is encountered. If the tooth is partially erupted necessary. If the MTA is short of the apex it may be mois-
tened and advanced a little further with pluggers. As the
material takes 3–4 hours to set, if necessary, it can readily

220

Endodontic aspects of traumatic injuries Chapter | 12 |

AB

CD
Figure 12.11  (A) The maxillary left central incisor has become non-vital after a traumatic injury; the root canal is wider than
that of the right central incisor, signifying that the tooth has been non-vital for some time. (B) The root canal has been
disinfected and the apical 4 mm filled with MTA. (C) The canal was then back-filled with gutta-percha and the neck of the
tooth filled with etched and bonded composite resin. (D) One year later, healing has taken place.

221

Harty’s endodontics in clinical practice

Table 12.1  Advantages of MTA over calcium at the neck of the tooth12 (Fig. 12.12). The neck of the
hydroxide for managing the immature tooth with an tooth may be reinforced using etched and bonded com-
open apex posite resin, allowing space, if indicated, for a post.64,65 If
little coronal tissue remains, a fibre post may be cemented
• Reduced number of treatment appointments. into the root canal. Compared to metal posts, fibre posts
• Less demanding on both clinical and patient time. have the advantage of some flexibility; if it fails, it is more
• Less stressful for the patient in terms of overall likely to become decemented rather than cause a root
fracture.66
treatment duration.
• Equal or more favourable treatment outcome. Surgical Treatment
• Reduced risk of root fracture. of Immature Teeth
• Reduced risk of reinfection due to loss of temporary
If attempts to eliminate infection from the periapical
filling. tissues are, ultimately, unsuccessful, then a surgical
• Greater cost of material more than offset by reduced approach may be indicated. In an apprehensive child,
sedation or general anaesthesia may be necessary and
treatment time. appropriate consent should be obtained. Surgery may, for
example, be necessary to look for a longitudinal root frac-
be removed at this stage using root canal files and thor- ture; if present, the tooth would need to be extracted. If
oughly washing with sterile water. apical surgery is to be undertaken, the root canal is nor-
mally filled first, and the root canal filling cut back during
When correct placement is confirmed, it is allowed to surgery to allow placement of a root-end filling of MTA.
set; a moist cotton pellet may be temporarily inserted into Further details on endodontic surgery are covered in
the canal and the access cavity sealed. At a subsequent Chapter 10.
visit, the canal may be back-filled with gutta-percha
(Obtura III Max, Obtura Spartan, Earth City, MO, USA) Revascularization Treatment
(Fig 12.11). Alternatively, this may be done immediately of Immature Teeth
after placing the MTA but there is a high risk of disturbing
the unset MTA plug. Many operators now fill the whole A recent development in treatment of these teeth is to
canal with MTA if there is no contraindication rather than clean the root canal and dress with a triple antibiotic paste
back-filling with gutta-percha. If the apex is wide open, it of ciprofloxacin, metronidazole and minocycline. Care
may be helpful to pack a little sterile resorbable material should be taken to avoid discolouration resulting from the
at the apex to limit extrusion of the MTA (Surgicel, Johnson use of minocycline.67 When the canal is considered clean
and Johnson Medical Ltd.). MTA is extremely ‘tissue and disinfected, bleeding is induced at the apex and MTA
friendly’ and extrusion of a little of the material does not is placed, about 3 mm apical to the cervical constriction,
seem to adversely affect the outcome. This technique can over the subsequent blood clot. This method has been
be demanding as it is difficult to pack the material cor- shown to enable continued root growth and thickening of
rectly at the apex; magnification and good lighting are the walls of the root, which is, obviously, a tremendous
essential so an operating microscope is invaluable. It is advantage as it overcomes the problems of a non-vital
recommended that this treatment should be undertaken immature tooth with very thin walls being prone to frac-
by a specialist. Adequate time must be allowed, as revision ture. The tissue within the pulp space may not be normal
of the filling at a subsequent visit is very challenging. Some pulp, but derived from cells of surrounding tissue. A
authorities cite cost as a contraindication to the use of number of case series have been published showing
MTA; however, the clinical time saved due to the reduced success with this treatment, which appears very
number of treatment appointments more than offsets the promising.10,67–75
cost of the material (Table 12.1) Some specialist groups
still include the calcium hydroxide method in their guide-
lines on account of the availability and lower cost of
calcium hydroxide, but the opinion is emerging that the
MTA is preferable and superior.

Avoidance of Cervical Regenerative Treatment of
Root Fracture Immature Teeth

Non-vital immature teeth have thin roots with weak This requires stem or progenitor cells, a scaffold to provide
dentine walls, and are especially at risk of root fracture a micro-environment for cell growth and differentiation,

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Endodontic aspects of traumatic injuries Chapter | 12 |

Apical to the part of the root which had formed by the
time of transplantation, the root should grow and mature
normally.79 Should the pulp become necrotic, root canal
treatment is complicated and is best referred to a specialist
for management.

COMPLICATIONS

Figure 12.12  The maxillary central incisor suffered a cervical External inflammatory
root fracture during long term calcium hydroxide treatment root resorption
and before root canal treatment was completed.
This may occur if infection develops in the pulp space and
and a signalling mechanism. This technique is under there is damage to the adjacent cementum; this is common
development and not as yet at the stage of being used in the more severe luxation injuries.49,50 Microorganisms
clinically; however, it appears promising for the and their toxins may track along the dentinal tubules to
future.68,76,77,78 the surface of the root, where the resultant inflammatory
reaction attracts osteoclasts, which may destroy a large
part of the root within a few weeks (Fig. 12.13). Inflam-
matory resorption is diagnosed radiologically as a local-
ized area of tooth resorption with a radiolucent area in the
adjacent bone. This may occur particularly rapidly in
immature teeth, which have thin roots and wide dentinal
tubules. It is, therefore, very important to take frequent
radiographs and to disinfect the pulp space promptly if
this type of resorption is seen. This will halt the resorption
and the periodontal structures should heal.80

The root canal must be thoroughly cleaned with
sodium hypochlorite to kill microorganisms. Calcium
hydroxide is then inserted and will create an unsuitable
environment for the continued survival of microorgan-
isms in the pulp space or dentinal tubules; it also raises
the pH, which discourages osteoclastic activity.80 When the
infection is controlled, the root canal can be filled. Should
the coronal seal subsequently fail, microorganisms may
re-enter the root canal and potentially stimulate further
resorption.

AUTO-TRANSPLANTATION OF Cervical external inflammatory
AN IMMATURE PREMOLAR INTO root resorption
THE INCISOR SPACE
Sometimes, a late complication of trauma, particularly
This may be undertaken in a patient who requires extrac- luxation, is inflammatory resorption close to the neck of
tion of premolars as a part of orthodontic treatment. It has the tooth (Fig. 12.14). This may occur in vital as well as
a high success rate but relies on careful case selection and root filled teeth and is often unrelated to the pulpal status,
meticulous surgical technique. The premolar must be as infection has entered from the damaged root surface.50,81
immature, preferably with the root length nearly complete The resorption spreads around the root canal rather than
and the apex open. Great care must be taken not to into it. Cervical resorption may be difficult to differentiate
damage the cementum at the neck of the tooth as this may radiologically from internal resorption. However, if two
cause cervical resorption. The desired outcome is that the views are taken at different horizontal angles, the lesion
pulp of the transplanted tooth should revascularize, and in cervical resorption will be seen to change position;
remain vital. This is followed by pulp canal obliteration. it should be possible to distinguish the outline of the
root canal superimposed upon it. Root canal treatment,

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Harty’s endodontics in clinical practice

Figure 12.13  The maxillary right central incisor displays Figure 12.14  Cervical external inflammatory resorption
external inflammatory root resorption on the mesial aspect (arrowed) has occurred on the distal surface of the maxillary
(arrowed); there is a radiolucency of the bone adjacent to right lateral incisor approximately three years after trauma. If
that in the tooth. The pulp of the tooth became necrotic as surgical access is good, the defect may be repaired, or the
a consequence of a luxation injury. tooth may need to be extracted as in this example.

or retreatment, is not the appropriate method of dealing avulsions if the periodontal ligament is allowed to dry
with the problem. Where the condition is limited and out.49,50 Replacement resorption can be detected at follow-
surgical access is good, surgical repair of the defect may be up appointments; the tooth lacks mobility and when
undertaken. In the case of a vital tooth, only if it is con- approximately 20% of the surface is affected gives a ringing
sidered that surgical repair will expose the pulp, should note to percussion testing.84 The condition can often only
root canal treatment be undertaken. If the condition is be observed on radiographs much later when the root has
extensive or surgical access is poor, extraction is usually a moth-eaten appearance (Fig. 12.15). Because the cemen-
indicated. CBCT scanning is a very valuable method of tum barrier is damaged in replacement resorption, the
assessing the nature and exact location of the resorp- body treats the tooth as bone, and the tooth is gradually
tion.13,14 It has been suggested that cervical resorption may resorbed during physiological bone turnover and replaced
be associated with bleaching of non-vital teeth.55 However, by bone. In a healthy tooth, the cementum resists osteo-
this procedure should not cause damage if the dentine clastic activity. Being a physiological process, replacement
tubules of the root are protected and if sodium perborate resorption cannot be treated; therefore, carrying out root
and water rather than hydrogen peroxide are used.82,83 canal treatment is of no benefit. The tooth will ultimately
be lost, but the time taken is variable and depends on the
External replacement root rate of bone turnover. In some young patients it can
resorption progress rapidly, and during the growth phase the anky-
losed tooth will inhibit local alveolar bone growth and so
This may occur when there is damage to the periodontal appear to sink into the jaw (infraposition) as the sur-
structures as in severe luxation injuries and especially with rounding alveolar bone grows.85,86 Early diagnosis and

224

Endodontic aspects of traumatic injuries Chapter | 12 |

important to have excellent access and vision to avoid
perforation. This treatment is best referred to a specialist.

Previous injury

Sometimes a patient presents with a new injury to an
already traumatized tooth and the history of the present-
ing injury may fail to correlate with the findings of the
clinical and radiological examinations and special tests.
The patient should be questioned specifically about a pre-
vious injury.

Root canal retreatment

If a patient presents with signs or symptoms related to a
root filled immature tooth and there are technical defi-
ciencies in the previous treatment, root canal retreatment
is indicated; it is, generally, more successful than surgery,
which is often complicated by a short root with thin walls.
Root canal retreatment is covered in Chapter 14. If the
technical quality of the previous treatment is already very
good, the possibility of recent root fracture must be
considered.

Figure 12.15  The maxillary right central incisor displays Tooth discolouration
replacement resorption on the mesial and distal root
surfaces; there is a moth-eaten appearance. The tooth had Since non-vital teeth tend to discolour, especially if
been replanted 2 hours after avulsion 1 year previously. necrotic pulp is allowed to remain within the pulp horns,
many patients request to have their teeth bleached. This
treatment planning is, therefore, important. Extraction of may be carried out, under rubber dam; root filling is
an ankylosed tooth in a growing patient is best avoided, removed to the cervical level and the canal entrance sealed
unless the space is to be closed, as alveolar atrophy will with, for example, glass ionomer cement. Smear layer
follow. Before or during the growth spurt, if there is no from the access cavity is removed using an etching agent
infection present, the crown and any root filling may be and a thick paste of sodium perborate and water inserted.
removed and the root retained to preserve alveolar A temporary dressing is placed over this and the patient
bone.85–87 If growth is nearly complete it may be appropri- recalled after 1 week. At this visit, the colour improvement
ate to restore the incisal edge to improve its appearance. is assessed and the treatment may be repeated if required.
In older patients the tooth can be left until symptoms arise When the desired lightening is achieved, the access
from later infection. cavity is then restored with composite resin. Care must be
taken that the root filling is removed to the cervical con-
Barrier formation coronal striction but not further beyond, to reduce the risk of cervi-
to the apex cal external resorption, which has been reported following
bleaching.88 Alternatively, instead of bleaching, a veneer
If vital tissue remains at the apex, and a material such as or crown may be necessary.
calcium hydroxide is placed short of the apex, a calcific
barrier may form coronal to the apex. This may be desir- ORTHODONTIC TREATMENT
able if the apical portion remains vital. However, if sub-
sequent infection occurs, treatment will be required. If the Orthodontists are very concerned about causing resorp-
barrier is near the apex, apical surgery may be the treat- tion of root filled, previously traumatized teeth during
ment of choice. If it is more coronal, it may be necessary tooth movement. However, there is no scientific evidence
to instrument through the barrier. In this case it is very to show that these teeth are more at risk than vital ones.89,90
It is essential that root canal treatment has been carried
out properly prior to orthodontic movement and that

225

Harty’s endodontics in clinical practice

infection has been eliminated; where there is any concern • understand the importance of correct diagnosis and
about the technical quality of the root canal filling, the
root canal treatment should be redone first. There is no treatment planning in cases of trauma
hard evidence to support the clinical practice of dressing
teeth with calcium hydroxide and delaying placement of • treat simple traumatic injuries
the permanent root filling until the completion of ortho- • recognise the significance of and be familiar with
dontic treatment. This practice incurs increased risk of
microleakage or loss of the temporary restoration and the methods of preserving pulpal vitality in immature
canal becoming reinfected. It also causes additional incon-
venience and stress to the patient, as well as risking further teeth
complications like root fracture if the tooth is repeatedly
opened to replace the calcium hydroxide.52,91 • appreciate that elimination of infection from the

LEARNING OUTCOMES root canal system is critical to achieving a favourable

After reading this chapter the reader should be treatment outcome
able to:
• discuss modern, and the shortcomings of older,

endodontic techniques for treating non-vital

immature teeth

• know when it is appropriate to refer a complex case
• describe the common complications following dental

trauma and their management.

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Chapter 13 

Marginal periodontitis and the dental pulp

I. Rotstein, J.H. Simon

CHAPTER CONTENTS assessment. Aetiological factors such as microorganisms,
as well as contributing factors such as trauma, root resorp-
Summary 231 tion, perforation and dental malformation play a role in
Anatomical considerations 231 the development and progression of such diseases. Treat-
Effect of inflamed pulp on the ment and prognosis of endodontic-periodontal diseases
periodontium 232 vary and are dependent on the aetiology, pathogenesis
Effect of marginal periodontitis on the and correct recognition of each specific condition. There-
pulp 233 fore, understanding the interrelationship between endo-
Classification 233 dontic and periodontal diseases will enhance the clinician’s
233 ability to establish correct diagnosis, assess the prognosis
Primary endodontic lesion 233 of the teeth involved and select a treatment plan based on
Primary periodontal lesion 235 biological and clinical evidence.
Combined lesions 242
Diagnosis 242 ANATOMICAL CONSIDERATIONS
Prognosis 242
Complications due to radicular anomalies 243 The dental pulp and the periodontium are intimately
Diagnosis 243 related and connected via exposed dentinal tubules, lateral
Prognosis 243 or accessory canals, and the apical foramen.1–14 Exposed
Treatment 244 dentinal tubules in areas devoid of cementum may serve
Alternatives to implants 244 as viable communication pathways between the dental
Anatomical redesigning 244 pulp and periodontal ligament. Exposure of dentinal
Root amputation 246 tubules may occur due to developmental defects, disease
Tooth resection 247 and following periodontal or surgical procedures. Radicu-
Bicuspidization 248 lar dentinal tubules extend from the pulp to the cemento-
Learning outcomes 250 dentinal junction (CDJ). They run a relatively straight
References course and range in size from 1 to 3 µm in diameter.13 The
diameter of the tubules decreases with age or as a response
SUMMARY to chronic low grade stimuli causing apposition of highly
mineralized peritubular dentine. The number of dentinal
Endodontic-periodontal diseases often present challenges tubules varies from approximately 8000 mm−2 at the CDJ
to the clinician in their diagnosis, treatment and prognosis to 57 000  mm−2 at the pulpal end. In the cervical area
of the root the number of dentinal tubules is about
15 000 mm−2.13

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Harty’s endodontics in clinical practice

When the cementum and enamel do not meet at the potential pathway for the spread of microorganisms and
cemento-enamel junction (CEJ) these tubules remain their toxic byproducts from the pulp to the periodontal
exposed thereby creating pathways of communication ligament and vice-versa, resulting in an inflammatory
between the pulp and the periodontal ligament. Patients process in the involved tissues.
experiencing cervical dentine hypersensitivity are an
example of such a phenomenon. Fluid and irritants may The apical foramen is the principal route of communi-
flow through patent dentinal tubules. In the absence of an cation between the pulp and periodontium. Microbial and
intact enamel or cementum layer, the pulp can become inflammatory byproducts may exit readily through the
exposed to the oral environment via the gingival sulcus or apical foramen to cause periapical pathosis. The apex is
periodontal pocket. Experimental studies demonstrated also a potential portal of entry of inflammatory byprod-
that soluble material from bacterial plaque applied to ucts from deep periodontal pockets into the pulp. Pulp
exposed dentine can cause pulpal inflammation indicating inflammation or pulp necrosis extends into the periapical
that dentinal tubules may provide ready access between tissues causing a local inflammatory response often associ-
the periodontium and the pulp.15 ated with bone and root resorption.24 Endodontic therapy
aims to eliminate the intraradicular aetiological factors
Scanning electron microscopic studies have demon- thereby leading to healing of the affected periapical tissues.
strated that dentine exposure at the CEJ occurred in about
18% of teeth in general and in 25% of anterior teeth in EFFECT OF INFLAMED PULP
particular.16 In addition, the same tooth may have differ- ON THE PERIODONTIUM
ent CEJ characteristics presenting dentine exposure on one
surface while the other surfaces are covered with cemen- When the pulp becomes inflamed, it elicits an inflamma-
tum.17 This area is susceptible to the progression of endo- tory response in the periodontal ligament at the apical
dontic pathogens, as well as to the effect of root scaling foramen and/or adjacent to smaller openings of the
and planing on cementum integrity, trauma, and bleach- root canal system.25 Inflammatory byproducts of pulpal
ing-induced pathosis.18,19,20 Other areas of dentinal com- origin may permeate through the apex, smaller canals
munication may be through developmental grooves both in the apical third of the root canal system or exposed
palato-gingival and apical.21 The base of these grooves is dentinal tubules and trigger an inflammatory vascular
often not covered by cementum and accessory canals are response in the periodontium.26–33 Among those are living
often present. pathogens such as certain bacteria strains including spiro-
chetes, fungi and viruses,26,27,29,33–38 as well as non-living
Lateral and accessory canals can be present anywhere pathogens.37,39,40,41,42 Many of these are pathogens simi-
along the length of the root. Their incidence and location larly encountered in periodontal inflammatory disease. In
have been well documented in both animal and human certain cases, pulpal disease will stimulate epithelial
teeth using a variety of methods. These included dye growth affecting the integrity of the periapical tissues.43,44
perfusion, injection of impression materials, microradiog-
raphy, light microscopy and scanning electron micros- In an experimental study, defects of different sizes were
copy.2,4,6,8,10,14,22 It is estimated that 30–40% of all teeth created on root surfaces of extracted lateral incisors with
have other smaller canal systems and the majority of them open or mature apices. The canals were either infected or
are found in the apical third of the root. It was reported filled with calcium hydroxide and then replanted. It was
that 17% of teeth presented multiple canal systems in observed that intrapulpal infection promoted marginal
the apical third of the root, about 9% in the middle third, epithelial downgrowth on the denuded dentine surface
and less than 2% in the coronal third.4 However, it seems after 20 weeks.45 The effects of endodontic pathogens on
that the incidence of periodontal disease associated with marginal periodontal wound healing on dentinal surfaces
these types of canals is relatively low. A study of 1000 surrounded by healthy periodontal ligament have been
human teeth with extensive periodontal disease found assessed.46 It was found that in infected teeth the defect
only 2% of such canals associated with the involved peri- was covered by 20% more epithelium and the non-
odontal pocket.8 infected had 10% more connective tissue covering. It
appears that the pathogens in a necrotic canal can stimu-
Other canal systems in the furcation of molars may also late epithelial downgrowth along denuded dentine sur-
be a direct pathway of communication between the pulp faces with marginal communication.
and the periodontium.6,10 The incidence of accessory
canals may vary from 23% to 76%.2,4,23 These accessory The effect of endodontic infection on periodontal
canals contain connective tissue and blood vessels that probing depth and the presence of furcation involvement
connect the circulatory system of the pulp to that of the in mandibular molars have also been investigated.47 In
periodontium. However, not all these canals extend the 100 patients with molars with periapical lesions on both
full length from the pulp chamber to the floor of the furca- roots, the periodontal probing depth was significantly
tion.23 It was reported that pulpal inflammation may cause greater than around teeth without periapical lesions. It was
inflammatory reaction in the interradicular periodontal
tissues.24 The presence of these patent smaller canals is a

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Marginal periodontitis and the dental pulp Chapter | 13 |

suggested that root canal inflammation in molars involved CLASSIFICATION
with marginal periodontitis may potentiate periodontitis
progression by pathogens spreading through accessory There are many ways of classifying the so-called endodon-
canals and dentinal tubules causing more attachment loss tic-periodontal (endo-perio) lesions.24,52,59,60,61 For differ-
in the furcation. ential diagnostic and treatment purposes they are best
classified as endodontic, periodontal or combined dis-
Periodontal pathogens in pulp and periodontal diseases eases.62,63 They include:
affecting the same tooth were studied by means of 16S
RNA gene directed polymerase chain reaction samples 1. primary endodontic lesion
from 31 teeth.48 Specific polymerase chain reaction 2. primary periodontal lesion
methods were used to detect Actinobacillus actinomycetem- 3. combined lesions.
comitans, Bacteroides forsythicus, Eikenella corrodens, Fusobac-
terium nucleatum, Porphyromonas gingivalis Prevotella The combined lesions include:
intermedia and Treponena denticola. The pathogens were
found in all endodontic samples. In chronic apical peri- 1. primary endodontic lesion with secondary
odontitis and chronic marginal periodontitis the same periodontal involvement
pathogens were found. It was concluded that periodontal
pathogens often accompany endodontic infections and 2. primary periodontal lesion with secondary
support the concept that endodontic-periodontal interre- endodontic involvement
lationships are a critical pathway for both diseases. In
addition, foreign bodies and materials may also pass into 3. true combined lesions.
the periapical tissues. Extrinsic foreign bodies, including
foreign lipids, cellulose granulomas and iatrogenic materi- This classification is based on the theoretical pathways
als, can cause a direct inflammatory response. explaining how these lesions are formed.61 By understand-
ing the pathogenesis, the clinician can then suggest an
appropriate course of treatment and better assess the
prognosis.

EFFECT OF MARGINAL Primary endodontic lesion
PERIODONTITIS ON THE PULP
An acute exacerbation of a chronic periapical lesion on a
The effect of periodontal inflammation on the tooth with a necrotic pulp may drain coronally through
pulp is controversial and conflicting studies the periodontal ligament into the gingival sulcus (Fig.
abound.3,5,12,24,49,51,52,53,55,57,58 It has been suggested that 13.1A). This condition may mimic a periodontal abscess.
marginal periodontitis has no effect on the pulp, at least, However, it is only periodontal in that it passes through
until it involves the apex.3 On the other hand, several the periodontal ligament space (Figs 13.2–13.5). In reality,
studies suggested that the effect of periodontal disease on it is a sinus tract resulting from pulpal disease. Therefore,
the pulp is degenerative in nature including an increase in it is essential that a gutta-percha cone is inserted into the
calcifications, fibrosis and collagen resorption, as well as sinus tract and one or more radiographs taken to track the
a direct inflammatory effect.9,11 It appears that the pulp is origin of the lesion. When the sinus tract is probed, it is
usually not severely affected by periodontal disease until usually narrow and lacks width. A similar situation occurs
recession has opened an accessory canal to the oral envi- where drainage from the apex of a molar tooth extends
ronment. At that stage, pathogens leaking from the oral coronally into the furcation area (Fig. 13.6). Direct exten-
cavity through the accessory canal into the pulp may cause sion of inflammation from the pulp may also occur into
a chronic inflammatory reaction followed by pulpal the furcation area of a non-vital tooth when a lateral or
necrosis. However, as long as the accessory canals are pro- accessory canal is present (Fig. 13.7). Primary endodontic
tected by sound cementum, necrosis usually does not lesions usually heal following root canal treatment; the
occur. Additionally, if the mircovasculature of the apical sinus tract extending into the gingival sulcus or furcation
foramen remains intact the pulp will maintain its vitality.9 disappears at an early stage (usually within a few weeks)
With regard to the root apex, once the apical vasculature once the consequences of the necrotic pulp has been
is compromised, the pulp will lose its vitality. This is treated. It is important to recognize that an attempt to
shown in teeth with primary periodontal lesions with sec- provide periodontal therapy for this condition will result
ondary endodontic involvement (see later). The effect of in failure since if the necrotic pulp has not been diagnosed
periodontal therapy on the pulp is similar during scaling, and treated.
curettage or periodontal surgery if accessory canals are
opened to the oral environment. In such cases, pathogenic Primary periodontal lesion
invasion and secondary inflammation and necrosis of the
pulp can occur. These lesions (Fig. 13.1C) are caused by marginal perio-
dontitis, which progresses apically along the root surface

233

Harty’s endodontics in clinical practice

ND N VN
AC A

B

B

A B CD

Figure 13.1  Classification of endodontic-periodontal lesions. (A) Primary endodontic lesions: pathway extending from apex to
gingival sulcus via periodontium (A); apex to furcation (B); lateral canal to furcation (C); lateral canal to pocket (D). (B) Primary
endodontic lesion with secondary periodontal involvement. (C) Primary periodontal lesion extending to the apex. (D) Primary
periodontal lesion with secondary endodontic involvement via a lateral canal (A). Combined lesion from coalescence of
separate lesions (B). N = Necrotic pulp. V = Vital pulp.

A BC
Figure 13.2  Primary endodontic lesion. Mandibular premolar with a radiolucency along the distal surface of the root.
(A) Pretreatment, the lesion (arrowed) drained through the gingival sulcus. (B) Immediately after treatment, root canal sealer
can be observed in the sinus tract. (C) Six months later, there is evidence of healing and bone filling.

AB
Figure 13.3  (A) Mandibular molar with a narrow probable distal pocket and large radiolucency (arrowed). (B) Marked healing
apparent at one-year recall confirming that the original ‘pocket’ was of endodontic origin.
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Marginal periodontitis and the dental pulp Chapter | 13 |

AB

Figure 13.4  Success following treatment of a primary endodontic lesion. (A) Immediate post-treatment radiograph of a
mandibular canine showing mesial radiolucency (arrowed). (B) Radiograph at 15 months showing healing.

until the apical region is reached. In such conditions, pulp both endodontic and periodontal treatments. If the endo-
sensitivity testing will reveal a clinically normal pulpal dontic therapy is adequate, the prognosis depends on the
response (Figs 13.8 & 13.9). In addition, a probable severity of the marginal periodontal damage and the effi-
pocket that has width is anticipated, possibly becoming cacy of periodontal therapy. With endodontic therapy
progressively shallower as the probe is moved laterally; alone, only part of the lesion will heal to the level of the
there is also an accumulation of plaque and frequently secondary periodontal lesion.
calculus. The prognosis in this condition depends wholly
upon the stage of the marginal periodontitis and the effi- Primary endodontic lesions with secondary periodontal
cacy of periodontal therapy. The clinician must also be involvement may also occur as a result of root perforation
aware of the radiographic appearance of marginal perio- during root canal treatment, or where pins or posts have
dontitis associated with developmental radicular anoma- been misplaced during coronal restoration (Fig. 13.10).
lies (see later). Symptoms may be acute, with periodontal abscess forma-
tion associated with pain, swelling, exudation of pus,
Combined lesions pocket formation and tooth mobility. A more chronic
response may sometimes occur without pain, and involves
Primary endodontic lesion with secondary the sudden appearance of a pocket with bleeding on
periodontal involvement probing or exudation of pus. When the root perforation
is situated close to the alveolar crest, it may be feasible to
If, after a period of time, a suppurating primary endodon- raise a flap and repair the defect with an appropriate filling
tic lesion remains untreated, it may become secondarily material and subsequently reposition the flap apically to
involved with marginal periodontal breakdown (Fig. expose the repaired perforation. In deeper perforations, or
13.1B). Biofilm forms at the gingival margin of the sinus in the roof of the furcation, immediate internal repair of
tract and leads to marginal periodontitis. When plaque or the perforation has a better prognosis than management
calculus is encountered upon probing, the treatment and of an infected one. Many materials have been used for
prognosis of the tooth are altered; the tooth now requires this purpose. Today, Mineral Trioxide Aggregate is most
widely used.64,65

235

AB

CD
Figure 13.5  Mandibular molar with apical lesion extending into furcation. (A) Preoperative radiograph showing furcal and
distal radiolucency. (B) Clinical photograph of gingival swelling and a periodontal probe in the furcation. (C) A 1-year recall
radiograph showing furcal and distal radiolucencies healing. (D) Clinical photograph showing minimal pocket depth on the
buccal. Healing occurred following root canal treatment alone.

AB
Figure 13.6  Mandibular molar where apical involvement extends into the furcation (arrowed). (A) Immediately following root
canal treatment, excess sealer is present at the apex of the distal root. (B) Radiograph 11 years later showing apical and
furcation healing.
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Marginal periodontitis and the dental pulp Chapter | 13 |

AB

Figure 13.7  Primary endodontic lesion with a lateral canal demonstrated in the furcation. (A) Post-treatment radiograph
demonstrating filling material passing through openings into the furcation (arrowed). (B) After 18 months, complete healing
of the lesions at the apex and adjacent to the lateral canal is demonstrated.

have become an increasing problem with molar teeth that
have been treated by root resection. In a study of 100
patients, a total of 38 teeth failed during the 10-year
period of observation, and 47% of the failures were due
to root fractures, with the vast majority being in mandibu-
lar molar teeth.54,56

Figure 13.8  Primary periodontal lesion. A mandibular molar Primary periodontal lesion with secondary
presented with a probable distal pocket (arrowed). Pulp endodontic involvement
testing was positive indicating a lesion of periodontal origin;
the tooth was extracted. The apical progression of a periodontal pocket can con-
tinue until the apex is reached. As a result, the pulp may
Root fractures may also present as primary endodontic become necrotic due to irritants permeating via a lateral
lesions with secondary periodontal involvement. These canal or the apical foramen (Fig. 13.1D). In single rooted
typically occur on root-treated teeth (Fig. 13.11), often tooth the prognosis is usually poor, which is the opposite
with post crowns in situ. The signs may range from a of that for the primary endodontic lesion. In molar teeth
local deepening of a periodontal pocket to more acute not all the roots may suffer the same loss of supporting
periodontal abscess formation. In addition, root fractures tissues to the apex, in which case the possibility of root
resection should be considered.

The treatment of marginal periodontitis can also lead to
secondary endodontic involvement. Lateral or accessory
canals and dentinal tubules can be opened to the oral
environment by curettage, scaling or surgical flap proce-
dures (Figs 13.12 & 13.13). In addition, it is possible for
a blood vessel within a lateral canal to be severed by a
curette during treatment. Also, pulp changes resulting
from marginal periodontitis were observed when the main
apical foramen was involved.9 Provided the blood supply
through the apex is intact, the pulp has a strong capacity
for survival (Fig. 13.10).

237