Anatomy, Radiographic Anatomy and Cephalometrk Landmarks
2.40 Anatomy of the soft tissue
profile.
1 trichion
2 superior crease
3 supraorbital ridge
4 forehead
5 glabella
6 root of the nose
7 nasal bridge
8 tip of the nose
9 nasal base
10 nasal septum
11 nostril
12 ala of the nose
13 cheek
14 philtrum
15 upper lip
16 lower lip
17 chin
18 lateral canthus
19 angle of the mouth
20 soft tissue menton
2.41 Radiograph of the
soft tissue profile.
1 forehead
2 nasal bridge
3 tip of the nose
4 base of the nose
5 upper lip
6 lower lip
7 chin
8 eye
9 cheek
10 ala of nose
1 1nostril
2.42 Cephalometric landmarks related to
the soft tissue profile.
SI
Orthodontic Cephalometry
DENTITION Radiographic anatomy (2.44, p.54)
In the deciduous dentition (2.44A), the deciduous
Anatomy (2.43) teeth (1) appear as radio-opaque structures. Their
A specific characteristic of the development of the long axes are nearly perpendicular to the occlusal
dentition is that the crown of a tooth is calcified to plane and are parallel t o each other. The successors
the ultimate dimension before it emerges into the appear as radio-opaque follicles in the alveolar
oral cavity. The deciduous teeth emerge, while their bone. The p e r m a n e n t central incisors (2, 3) are
successors develop below. The eruption of the per situated lingually to the deciduous incisors (1). The
manent teeth mesial to the first molars is associated maxillary central incisors (2) lie beneath the nasal
with resorption of the roots of the predecessors and floor (4). Vertically the canines ( 5 , 6) are the teeth
their investing alveolar bone. that are placed furthest from the occlusal plane. The
maxillary canines (5) lie above or at the nasal floor
In the deciduous dentition (2.43A), which usually (4). The mandibular canines (6) lie close to the lower
completes by the age of t w o and a half years, the border of the mandibular body (7). The crowns o(
maxillary incisors (1) are related to the mandibu- the bicuspids (8, 9) are formed beneath the roots
lar incisors (2) with an edge-to-edge bite. The buccal of the deciduous molars (10, 11). The first perma
cusps of the maxillary molars (3, 4) overlap the nent molars (12, 13) are situated distally to the
buccal cusps of the mandibular molars (5, 6). All deciduous second molars (11).
maxillary teeth except the deciduous second molars
(4) occlude with the two opposing teeth. The distal In the mixed dentition (2.44B), the permanent
contours of the maxillary and mandibular second incisors (2, 3) erupt labially. Their inclination
molars (4, 6) are tangential to the perpendicular line relative t o the occlusal plane is more oblique than
of the occlusal plane. that of the deciduous incisors. The permanent
canines (5, 6) erupt toward the roots of the perma
The mixed dentition (2.43B) begins with the nent lateral incisors (14). The bicuspids (8, 9) erupt
eruption of the permanent central incisors (7) and straight occlusally, corresponding with the resorp
the first molars (8, 9). The permanent central tion of the roots of the deciduous molars (10, 11).
incisors which are lingual to the predecessors erupt The first permanent molars (12, 13) drift mesially
in an oblique direction towards the deciduous as they erupt into the oral cavity.
incisors. After the exfoliation of the deciduous teeth,
the permanent central incisors continue to erupt In the permanent dentition (2.44C), all perma
labially and become upright later by the influence nent teeth erupt into the oral cavity. For cephalo-
of the opposing teeth and the musculature. Before metric analysis, the positions of the most prominent
the exfoliation of the deciduous second molars (4, incisors (2, 3) and the first molars (12, 13) are iden
6) the first permanent molars (8, 9) erupt with the tified. T h e maxillary incisors (2) lie between the
cusp-to-cusp relationship. labial and lingual aspects of the alveolar process (15,
16), which extend u p w a r d s from rhe cervical area
In the permanent dentition (2.43C), all remain of the teeth and merge with the radio-opaque
ing permanent teeth erupt and establish occlusal s h a d o w of the hard palate (17). T h e apex of the
contact with their counterpart teeth. The maxillary central incisor is helpful in identifying the subspinale
teeth overlap the mandibular teeth in buccolabial point as it usually lies posterior to this point. The
direction. In centric occlusion all maxillary teeth first maxillary molars (12) are situated below the
except the central incisors occlude half a tooth distal key ridge (18). Their apices may be masked by the
to their opposing teeth. In normal occlusion the shadow of the hard palate (17), by the inferior wall
mesiolingual cusp of the maxillary first molar (8) of the maxillary sinus (19), or by both these struc
occludes with the central fossa of the mandibular tures. The mandibular incisors (3) lie between the
first molar (9). external and the internal cortical plates of the sym-
physis (20, 21). The apex of the mandibular incisor
is a helpful area to identify the supramentale point
as it usually lies posterior to and slightly above the
supramentale point.
52
Anatomy, Radiographk Anatomy and Cepbalometrk Landmarks
Cephalometric landmarks (2.45, p.54) Isi - incision superius incisalis - the incisal edge
1 APOcc - anterior point for the occlusal plane - a of the maxillary central incisor;
LI - mandibular central incisor - the most labial
constructed point, the midpoint of the incisor point on the crown of the mandibular central
overbite in occlusion;
• Iia - incision inferius apicalis - the root apex of incisor;
the most anterior mandibular central incisor; if L6 - mandibular first molar - the tip of the
this point is needed only for defining the long axis mesiobuccal cusp of the mandibular first perma
of the tooth, the midpoint on the bisection of the nent molar;
apical root width can be used;
• Iii - incision inferius incisalis - the incisal edge of PPOcc - posterior point for the occlusal plane -
the most prominent mandibular central incisor; the most distal point of contact between the most
• Isa - incision superius apicalis - the root apex of posterior molars in occlusion (Rakosi);
the most anterior maxillary central incisor; if this III - maxillary central incisor - the most labial
point is needed only for defining the long axis of point on the crown of the maxillary central
the tooth, the midpoint on the bisection of the
apical root width can be used; incisor;
U6 - maxillary first molar - the tip of the
mesiobuccal cusp of the maxillary first permanent
molar.
2.43 Anatomical characteristics of natural deciduous dentition
(A), mixed dentition (B) and permanent dentition (C).
1 deciduous maxillary incisor
2 deciduous mandibular incisor
3 deciduous maxillary first molar
4 deciduous maxillary second molar
5 deciduous mandibular first molar
6 deciduous mandibular second molar
7 permanent maxillary central incisor
8 permanent maxillary first molar
9 permanent mandibular first molar
53
Orthodontic Cephaiometry
2.44 Radiographic anatomy of natural deciduous dentition (A), mixed dentition (B) and
permanent dentition (C).
1 deciduous incisor
2 permanent maxillary central incisor
3 permanent mandibular central incisor
4 nasal floor
5 permanent maxillary canine
6 permanent mandibular canine
7 lower border of the mandibular body
8 first bicuspid
9 second bicuspid
10 deciduous first molar
I I deciduous second molar
12 permanent maxillary first molar
13 permanent mandibular first molar
14 permanent lateral incisor
15 labial aspect of the alveolar process
16 lingual aspect of the alveolar process
17 hard palate
18 key ridge
19 inferior wall of maxillary sinus
20 external cortical plate of symphysis
21 internal cortical plate of symphysis
2.45 Cephalometric landmarks related to the
dentition.
54
Anatomy, Radiographic Anatomy and Cephalometric Landmarks
PHARYNX part of the ramus (3) and terminates at the level of
the inferior border of the sixth cervical vertebra (4)
Anatomy (2.46, p.56) where it is continuous with the oesophagus.
The pharynx is a median fibromuscular tube that At the roof and the upper part of the posterior
extends from the base of the skull. Jt is made up wall of the pharyngeal space, the adenoid (5) can be
from the sphenoid (1) and the occipital bones (2) to identified as a radio-opaque mass extending
the level of the sixth cervical vertebra (3), where it between the inferior surface of the sphenoid body
is continuous with the oesophagus (4). The pharynx (1) and the anterior arch of the atlas (6), which
is open anteriorly to the nasal cavity (5), the oral appears as a triangular radio-opaque area.
cavity (6), and the larynx (7). It is divided into three
parts: the nasopharynx, the oropharynx, and the Anterior to the adenoid is the pharyngeal space
laryngopharynx. of the nasopharynx (7). This is a boomerang-
shaped, radiolucent area that extends from the
Nasopharynx inferior surface of the sphenoid bone to the superior
surface of the soft palate. The soft palate (8) appears
The nasopharynx (8) is the upper part of the as a light radio-opaque area with a boomerang
pharynx. It is situated behind the oral cavity (6) shape. It projects downward and backward from the
above the soft palate (9). Its superior border is the posterior part of the hard palate (9). Inferior to the
base of the skull (1, 2). In the posterior part of the soft palate is the palatine tonsil (10), which is a light
roof and the upper part of the posterior wall, there radio-opaque oval area.
is an accumulation of lymphoid tissue - the adenoid
or pharyngeal tonsil (10) - which may be prominent Below the soft palate (8) and the palatine tonsil
in children but which becomes indistinct in adult (10) is the tongue (11), identified as a radio-opaque
hood. In the lateral wall, 1.5 cm posterior to the curve extending to the level of the hyoid bone (12).
inferior nasal concha (11), is the opening of the Posterior to the pharyngeal part of the tongue (11)
udirory tube (12). The nasopharynx (8) extends is the epiglottic fossa (13), seen as a triangular radi
downwards and is continuous with the oropharynx olucent area. The epiglottic fossa separates the pha
■(13) at the level below the soft palate (9). ryngeal part of the tongue (11) from the epiglottis
(14), which appears as a triangular radio-opaque area.
Ore-pharynx
The radiolucent area between the soft palate (8)
The oropharynx (13) is the middle part of the and the superior surface of the epiglottis (14) is the
pharynx situated between the soft palate (9) and the pharyngeal space of the oropharynx (15). Below the
superior border of the epiglottis (14). Anteriorly it epiglottis (14) is the pharyngeal space of the laryn
is open to the oral cavity (6) and is bordered by the gopharynx (16), which can be identified as a radi
posterior one third of the tongue (15). At the lateral olucent area extending to the level of the sixth
boundaries of the opening of the oral cavity (6) into cervical vertebra (4). When roentgenocephalomet-
the oropharynx (13), the palatine tonsils are lodged ric evaluation of the tongue is intended, its midline
inthetonsilar fossae. should be coated with a radio-opaque paste
(Oesophague paste) for better imaging (lngervall
andSchmoker, 1990).
larpgopharynx Cephalometric landmarks (2.48, p-57)
The laryngopharynx (16) is the lower part of the • ans - anterior nasal spine;
pharynx. It extends from the superior border of the • apw - anterior pharyngeal wall;
epiglottis (14) to the inferior border of the sixth • hy - hyoid;
ervical vertebrae (3), where it becomes continuous • pns - posterior nasal spine;
• ppw - posterior pharyngeal wall;
'th the oesophagus (4). The upper part of the • pt - posterior point of tongue;
aryngopharynx (16) is open anteriorly to the larynx • ptm - pterygomaxillary fissure;
7} via the patent inlet. • spw - superior pharyngeal wall;
• U - tip of uvula;
Radiographic anatomy (2.47, p.56) • Uo - point on the oral side of the soft palate;
'tarring from the junction of the anterior and • U p - point on the pharyngeal side of the soft
inferior surfaces of the sphenoid body (1), the roof
nd the posterior wall of the pharyngeal tract palate;
ppear as a radio-opaque line that descends anterior • ut - upper point of tongue.
the cervical vertebrae (2). It crosses the middle
55
Orthodontic Cephalometry
2.46 Anatomy of pharynx.
1 sphenoid bone
2 occipital bone
3 the sixth cervical vertebra
4 oesophagus
5 nasal cavity
6 oral cavity
7 larynx
8 nasopharynx
9 soft palate
10 adenoid o r pharyngeal tonsil
1 1inferior nasal concha
12 opening of the auditory tube
13 oropharynx
14 epiglottis
15 tongue
16 iaryngopharynx
2.47 Radiographs of the pharynx
1 sphenoid bone 10 palatine tonsil
2 cervical vertebra
3 mandibular ramus I I tongue
4 the sixth cervical vertebra 12 hyoid bone
5 adenoid 13 epiglottic fossa
6 anterior arch of the atlas 14 epiglottis
7 nasopharynx 15 oropharynx
8 soft palate 16 Iaryngopharynx
9 hard palate
56
Anatomy, Radiographic Anatomy and Cepbalometric Landmarks
2.48 Cephalometric landmarks related to the pharynx.
ans
CERVICAL VERTEBRAE The first and second cervical vertebrae (Cl and
C2) have distinctive morphology. The first cervical
Anatomy (2.49, p.59) vertebra (Cl) is known as the atlas (2.49B). It is the
Thecervical vertebrae make up the upper part of the only vertebra that has no body, and thus the spinous
vertebral column. There are seven cervical vertebrae processes of Cl form a ring bone. The vertebral arch
(C1-C7). A typical cervical vertebra (2.49A) can be divided into two parts: the anterior arch and
consists of a body and a vertebral arch. the posterior arch.
The body (1) is the anterior part of the vertebra. The anterior arch (8) has the anterior tubercle (9)
It resembles a segment of an ovoid rod. The verte for muscular attachment. The posterior arch (10)
bral arch attaches posteriorly to the body and sur has the posterior tubercle (11) instead of the spinous
rounds the spinal cord. Each arch consists of two process. The superior articular facets (12) are
pedicles and two laminae. The pedicles (2) arise concave with a kidney shape for the reception of the
from posterolateral aspects of the body (1). The occipital condyles of the skull. The inferior articu
laminae (3) spring from the pedicles. On each side lar facets (13) are round and almost flat for articu
of the junction between the pedicle (2) and the lation with the second cervical vertebra. In the
lamina (3) is a transverse process projecting later lateral mass there is the transverse foramen (5).
ally. The transverse processes (4) of the cervical ver
tebrae each have a characteristic transverse foramen The second cervical vertebra (C2), known as the
(S), which transmits the vertebral artery to the brain. axis (2.49C), is characterized by the presence of the
At the junction of the pedicle (2) and the lamina (3) dens or odontoid process. The dens (14) is a tooth-
are the superior articular process and inferior artic like process that projects superiorly from its body
ular process, which bear articular facets (6) that (1) and articulates with the anterior arch of the atlas.
form synovial joints with the adjacent vertebrae. At The process represents the transposed body of the
the meeting of the two laminae (3), there is a spinous atlas and acts as the pivot around which the atlas
process (7) that projects posteriorly. rotates.
57
Orthodontic Cephalometry
The remaining cervical vertebrae (C3-C7) intervertebral disc space (18), which appears as a
(2.49D) have the basic components of typical ver radiolucent strip. At the midpoint between the third
tebrae and closely resemble each other. The size of and the fourth cervical vertebrae is the hyoid bone
these vertebrae increases caudally as they extend (19), which is situated anteriorly.
from the occipital condyles (15) to the thoracic ver
tebrae (16). Cephalometric landmarks (2.51, p.6l)
• cv2ap - the apex of the odontoid process of the
Radiographic anatomy (2.50, p.60)
Anteroinferior to the occipital condyle (1), which second cervical vertebra;
appears as a curved radio-opaque line, the anterior • cv2ip - the most inferoposterior point on the
arch of the atlas (2) can be identified as a small tri
angular radio-opaque area. The apex of the triangle body of the second cervical vertebra;
faces the posterior border of the mandibular ramus • cv2ia - the most inferoanterior point on the body
(3), while its base faces the odontoid process of the
axis (4). The central mass of the atlas, which bears of the second vertical vertebra;
the inferior articular facet (5), appears as a radio- • cv3sp - the most superoposterior point on the
opaque area superimposed on the radio-opaque
shadow of the odontoid process (4). Posterosuperior body of the third cervical vertebra;
to the inferior articular facet (5) is the superior artic • cv3ip - the most inferoposterior point on the
ular facet (6), which can be identified as a radio-
opaque area. Its superior border is concave and body of the third cervical vertebra;
corresponds with the contour of the occipital condyle • cv3sa - the most superoanterior point on the
(1). Next to the superior articular facet is the poste
rior arch (7) with the posterior tubercle (8). At the body of the third cervical vertebra;
superior border of the posterior arch (7) is a groove • cv3ia - the most inferoanterior point on the body
for the vertebral artery and the first cervical nerve (9).
of the third cervical vertebra;
The odontoid process (4) and the body of the axis • cv4sp - the most superoposterior point on the
(10) appear as a triangular radio-opaque area. The
odontoid process (4) represents the apex of the tri body of the fourth cervical vertebra;
angular points toward the occipital condyle (I). The • cv4ip - the most inferoposterior point on the
spinous process of the axis (11) appears as a radio-
opaque projection extending posteriorly. body of the fourth cervical vertebra;
• ev4sa - the most superoanterior point on the
The radiographic appearances of the third
cervical vertebra (C3) to the seventh cervical body of the fourth cervical vertebra;
vertebra (C7) are similar. The body of each of these • cv4ia - the most inferoanterior point on the body
cervical vertebrae (12) appears as a wedge-shaped
radio-opaque area situated behind the pharyngeal of the fourth cervical vertebra;
space (13). Posterior to the body is the spinous • cv5sp - the most superoposterior point on the
process (14). The transverse processes (15), the
superior articular process (16) and the inferior artic body of the fifth cervical vertebra;
ular process (17) appear as a radio-opaque area • cv5ip - the most inferoposterior point on the
superimposed on the shadow of the body (12) and
the spinous process (14). The body of each cervical body of the fifth cervical vertebra;
vertebra is separated from the adjacent ones by the • cv5sa - the most superoanterior point on the
body of the fifth cervical vertebra;
• cv5ia - the most inferoanterior point on the body
of the fifth cervical vertebra;
• cv6sp - the most superoposterior point on the
body of the sixth cervical vertebra;
• cv6ip - the most inferoposterior point on the
body of the sixth cervical vertebra;
• cv6sa - the most superoanterior point on the
body of the sixth cervical vertebra;
• cv6ia - the most inferoanterior point on the body
of the sixth cervical vertebra.
58
Anatomy, Radiographic Anatomy and Cepbalometric Landmarks
B(a)
B(b)
2.49 Anatomy of the cervical vertebrae. (A) Typical cervical 7 spinous process
vertebra. (B) The first cervical vertebra (atlas) (a and b). (C) The 8 anterior arch of the atlas
second cervical vertebra (axis). (D) The lateral aspect of the 9 anterior tubercle
cervical vertebrae (CI-C7). 10 posterior arch of the atlas
1 body I I posterior tubercle
2 pedicle 12 superior articular facet
3 lamina 13 inferior articular facet
4 transverse process 14 dens or odontoid process of the axis
5 transverse foramen 15 occipital condyle
6 articular facet 16 thoracic vertebra
59
Orthodontic Cephalometry
B
2.50 Radiograph of the lateral aspect of the cervical vertebrae (A 9 groove for the vertebral artery and the first cervical nerve
and B) (B reproduced by courtesy of D r E Hellsing, Hudinge, 10 body of the axis
Sweden). 11 spinous process of the axis
12 body of the third cervical vertebra
1 occipital condyle 13 pharyngeal space
2 anterior arch of the atlas 14 spinous process of the third cervical vertebra
3 mandibular ramus 15 transverse process
4 dens or odontoid process of the axis 16 superior articular process
5 inferior articular facet 17 inferior articular process
6 superior articular facet 18 intervertebral disc space
7 posterior arch 19 hyoid bone
8 posterior tubercle
60
Anatomy, Radiographic Anatomy and Cephalometrk Landmarks
2.5 I Cephalometrk landmarks of the cervical
vertebrae.
cv2ip
cv2ia V\.^*** cv3sp
cv3sa^ Vcv3.p
<*3taWVlw4sp
cv4sa f \
cv4ia * ^ Z - ^ | cv5sp
cv5sa p
J . \ cv5ip
cv5iat^_^^cv6sp
cv6sar^" /
Cv6ia£ -* cv6ip
REFERENCES Coben SE (1986) Basion Horizontal: An Integrated
Concept of Craniofacial Growth and Cephalometric
Athanasiou AE, Toutountzakis N , Mavreas D, Ritzau Analysis. (Computer Cephalometrics Associated:
M, Wenzel A (1991) Alterations of hyoid bone Jenkintown, Pennsylvania.)
position and pharyngeal depth and their relationships
after surgical correction of mandibular prognathism. Downs WB (1948) Variations in facial relations:
Am] Orthod Dentofacial Orthop 100:259-65. their significance in treatment and prognosis. Am
J Orthod 34:812-40.
Bjork A (1947) The face in profile. Suenska Tandlak
TW40(suppl5B):32-3. DuBrul EL (1980) Sicher's Oral Anatomy. (CV
Mosby: St Louis.)
Broadbent BH Sr, Broadbent BH Jr, Golden W H
(1975) Bolton Standards of Dentofacial Gjorup H, Athanasiou AE (1991) Soft-tissue and
Developmental Growth. (CV Mosby: St Louis.) dentoskeletal profile changes associated with
mandibular setback osteotomy. Am J Orthod
Burstone CJ (1958) The integumental profile. Am Dentofacial Orthop 100:312-23.
| J Orthod 44:1-25.
Graber T M (1972) Orthodontics, Principles and
Burstone CJ, James RB, Legan H, iMurphy GA, Practice. (WB Saunders: Philadelphia.)
Norton L (1978) Cephalometrics for orthognathic
surgery. / Oral Surg 36:269-77. 61
Coben SE (1955) The integration of facial skeletal
variants. Am J Orthod 41:407-34.
I
Orthodontic Cepbalotnetry
Hellsing E (1991) Cervical vertebral dimensions in Movers RE (1988) Handbook of Orthodontics.
8-, 11-, and 15-year-old children. Ada Odontol (Year Book: Chicago.)
Scand 49:207-13.
Rakosi T (1982) An Atlas and Manual of
Holdaway RA (1983) A soft-tissue ccphalometric Cepbalometric Radiography. (Wolfe: London.)
analysis and its use in orthodontic treatment
planning. Part L Am) Orthod 84:1-28. Ricketts RM (1968) Esthetics, environment and the
law of lip relation. Am J Orthod 54:272-89.
Ingervall B, Sehmoker R (1990) Effect of surgical
reduction of the tongue on oral stereognosis, oral Ricketts RM (1981) The Golden Divider. / Clin
motor ability, and the rest position of the tongue and Orthod 15:725-59.
mandible. Am / Orthod Dentofacial Orthop
97:58-65. Sassouni V (1955) Roentgenographic cephalomet
ric analysis of eephalo-facio-dental relationships.
Jacobson A, Caufield PW (1985) Introduction to Am J Orthod 41:734-42.
Radiographic Cephalometry. (Lea and Febiger:
Philadelphia.) Schwarz AM (1937) Lehrgang der Gebessregelung.
Ill Die schadelbezugliche Uniersuchung. IV Der
Mazaheri M, Krogman WM, Harding RL, Millard schddelbezugliche Befund. (Urban and Schwarzen-
RT, Mehta S (1977) Longitudinal analysis of growth berg: Berlin.)
of the soft palate and nasopharynx from six months
to six years. Cleft Palate J 14:52-62. Solow B, Tallgren A (1971) Natural head position
in standing subjects. Ada Odontol Scand
McMinn R M H , Hutchings RT (1977) A Colour 29:519-607.
Atlas of Human Anatomy. (Wolfe: London.)
Solow B, Tallgren A (1976) Head posture and cran-
Melsen B, Athanasiou AE (1987) Soft Tissue iofacial morphology. Am j Rhys Anthropoi
Influence in the Development of Malocclusion. (The 44:417-36.
Royal Dental College: Aarhus.)
Steiner CC (1962) Cephalometrics as a clinical tool.
In: Kraus BS, Riedel RA (eds) Vistas in
Orthodontics. (Lea and Febiger: Philadelphia)
131-61.
62
CHAPTER 3
Possibilities and Limitations of Various Cephalometric
Variables and Analyses
Rainer-Reginald Miethke
INTRODUCTION AND GENERAL Before describing the specific measurements that
CONSIDERATIONS are, in our opinion, meaningful, it is useful to
describe how our analysis developed. The author of
If we assume that cephalometric analyses are this chapter started his training in a traditional
valuable rools in the comprehensive diagnosis of German orthodontic department where patients
malocclusions and skeletal malformations, it would were treated only with removable appliances. The
be logical to choose the ideal analysis from among head of the department was very active scientifical
the existing ones. The next questions to arise are: ly and, therefore, had used cephalometric evaluation
Do we do this? Do we really select the best cephalo from the beginning of his academic carreer. To inten
metric analysis of all? How do we decide that our sify his knowledge in this area, he once had traced
method is superior to the rest? What are the short cephalograms taken from 400 skulls and analysed
comings of the ones we decide not to use? them using Schwar/.'s method (Schwarz, 1937) (3.1).
After this and other experiences, he came to the con
If we answer with honesty the main question - clusion that the individual variability of all para
why we choose 'our' cephalometric analysis and not meters was so large that cephalometric measurements
any other - we generally have to admit that we do could not help him significantly with the ortho
not decide; rather the decision is more or less forced dontic diagnosis of individual patients. He taught
on us. We had instructors before, during, or after us the Schwarz analysis but without great enthusi
our postgraduate training who convinced us in one asm.
way or the other that they had the answer to the key
question of which method of cephalometric evalu Our next exposure to ccphalometrics occurred
ation is best. We followed their advice - not a sci when we attended the first fixed appliance course,
entific approach to the solution of the given which was given in Berlin in 1971. There we were
problem! acquainted very systematically with a method called
the 'Bergen analysis' (Hasund, 1974) only to find
Still, this seems to be the only feasible approach out later that it was basically nothing else than a
because none of us can study, use, and gain suffi slightly modified Steiner analysis.
cient experience with all the existing analyses to be
able to make a fully informed decision as to which Because the author felt his training in fixed appli
is the best system. Anyone who attempted this ances would never become adequate through
would have retired from orthodontics before he had attending continuing education courses, he went to
come to the final conclusion. the USA, the motherland of this treatment modality.
There he learnt and practised many different
Let us come back to the basic question of which analyses. Routinely the department there used the
is the best cephalometric analysis. The only true analyses of Steiner (1953, 1960) and Downs (1948,
answer probably is: None or several! If one system 1952, 1956). After returning to Germany, the
of analysis was absolutely superior to all the others, author used these two analyses; however, gradual
then it is likely that every responsible, knowledge ly the original evaluations expanded. Influenced by
able orthodontist would have decided to use this lectures, courses, articles, and even discussions with
method exclusively. Since this is not the case, it colleagues, measurements of Jacobson (1975,1976),
seems more likely that several evaluation methods Bjork (1947), Jarabak and Fizzell (1972), and
for cephalometric X-rays are appropriate, ejpecial- Hasund (Hasund et al, 1984) were added. So finally
\lif they are used with common sense, experience, we seemed to have a very thorough and compre
and some critical distance. hensive cephalometric analysis.
63
Orthodontic Cephalometry
When the forms for this composite analysis had general agreement. At the same time, we also
to be reprinted, the author took a closer look at decided to bring all measurements into a more
them and realized that some measurements meant logical order and also to add a graphical represen
more to him than others, and that he primarily tation to the numerical analysis. The analysis thus
checked certain parameters to determine a patient's developed has been in use since then with only slight
problem. Because of this, the question of which modifications.
cephalometric parameters were the most useful was
discussed in a circle of experienced clinicians. It Before starting with cephalometrics, the clinician
turned out not to be too difficult to come to a should consider the basic problem of whether to
analyse cephalograms in the traditional way or in
3.1 Cephalometric analysis of Schwarz (1937)
w i t h r e s p e c t i v e average values. T h e basic
reference line is the Frankfort horizontal plane,
which is labelled here as O A (Ohr-Augebene:
ear-eye plane).
3.2 Reference points which were directly digitized (A) or 666 children and adolescents by Droschl (1984). (From Droschl,
calculated by the computer (B) during a cephalometric screening of 1984; reprinted with permission.)
64
Possibilities and Limitations of Variables and Analyses
a more modern way using electronic data process Another general question is: How do we interpret
ing (EDP). T h e general d e v e l o p m e n t goes t o t h e the results we have gained through a cephalomet
inclusion of cephalometric analyses in EDP ric analysis? Commonly this is done by comparing
programs or p r o g r a m packages. But sometimes a the measurements of an individual patient with ideal
problem arises because the only programs that are or average values. However, a serious problem with
available are those developed by famous o r t h o d o n such data is that one seldom knows exactly w h a t
tists. If one of these analyses is identical with the inclusion criteria were used for the study from
buyer's idea, the constellation is perfect. A problem which the values for our comparison are finally
arises, however, if the customer w a n t s to have a derived. Did they use patients with 'normal' or
slight change in a marketed EDP analysis because 'ideal' occlusions? Since it is possible to have a
many of the programs are inflexible. N o t all of the 'good' occlusion and yet still have an unattractive
big companies are willing to help or to give the user appearance, was this aesthetic aspect included in the
a possibility of changing the program himself. selection process? What was the age of the sample
Fortunately, this situation is becoming better, with and did it consist equally of both sexes? When was
an increase in the number of smaller companies that the sample collected; can we assume that average
care for personalized service, thus increasing the skull-face-dentition dimensions have not changed
competition. Finally, a n o t h e r alternative is to since then? A final question especially important for
develop an individual EDP cephalometric evaluation any orthodontist outside the USA is: How does my
that satisfies all personal ideas of an optimal population correspond with a sample which stems
program. from North America? But even within the USA this
problem exists, since there are some remarkable dif
That was what we did. Since preferences can ferences between individuals in the north and the
change because of scientific progress, the program south (Taylor and Hitchcock, 1966).
was structured in such a way that additions or omis
sions can be easily accomplished. W i t h o u t being Droschl (1984) proposed a solution to this
able to give any final advice t o a colleague w h o problem (3.2). He evaluated Austrian children of
starts with o r t h o d o n t i c s a n d has to make the both sexes aged between six and 15. At 15, patients
decision to purchase a cephalometric EDP program, are considered as adults, though we know by more
we would like him t o a c k n o w l e d g e a t least this recent studies that growth continues even beyond
problem and strive for its best solution under his this age (Behrents, 1989) (3.3). Droschl also
personal conditions. proposed cephalometric values for patients with
3.3 G r o w t h of an individual between 17 and 41 years as observed
by Behrents (1989). This adult's g r o w t h is expressed as a forward
rotation of the mandible (as well as the chin), which is typical in
males. There is always an increased prominence of the nose,
independent of the patient's sex. (From Behrents, 1989; reprinted
with permission.)
65
[
Orthodontic Qephalomeiry
Class II, Division 1 malocclusions. Since his sample demonstrated a relative stability of its size over time,
is well defined and is one that can be considered to we kept it constant for all age groups and only dif
be very close to the population of our area in central ferentiated between males and females.
Europe, it became the basis for the comparison data
of our analysis (Table 3.1). When using our cephalomerric analysis program,
it will ask first for the name of the patient, his date
One problem remained in that, although Droschl of birth, his sex, and the date the cephalometric X-
had measured many parameters, he had not ray was taken in order to correlate the patient's data
included several that are part of our analysis. with the appropriate norm data.
However, as cephalomctrics is, to a large degree,
applied geometry, it was possible to deduce the Furthermore, the computer program corrects the
missing measurements from other measurements, measured values in relacion to the true vertical
though admittingly in a few cases approximations plane, which is by definition a plane perpendicular
had co be made. At the end of this process, we had to the plane of the horizon of the earth (true hori
data for comparison that marched our patients opti zontal). (It is the impression of the present author
mally as far as population, sex, and age were con that the problem of the true vertical plane is often
cerned. The only exception is the 'second made more complicated than necessary. With a flat
generation* Holdaway soft tissue angle (Holdaway, floor and a cephalostat set up in a regular rectan
1983; Schugg, 1985), which has not been formally gular fashion, the lower border of the cassette or the
evaluated for a (central) European population, but X-ray image is parallel to the true horizontal.
which has been at least roughly adopted to age and Consequently, the anterior and posterior margins of
gender by Zimmer and Miethke (1989). A the X-ray cassette reflect the true vertical.)
somewhat similar problem occurred with the age
dependence of the Wits appraisal. However, since This seems to be very reasonable and is acknowl
a study by Bishara and Jakobsen (1985) (3.4) edged by several prominent orthodontic scientists
(e.g. Moorrees and Kean; 1958, Viazis, 1991;
Lundstrom and Lundstrom. 1992).
Wits Absolute Curves for Females
Absolute Curvet for Mate*
10 ■ >o
*...*..••" "♦"•■•♦..Jt ••
-5 ■ -T- T - T-V/- I
5 7 11 13 15 IT © LFT
AGE AGE
© LFT • A f T m SFT * AFT SFT 1
3.4 The change of the W i t s appraisal over time for males and Basically, the W i t s appraisal is stable, especially in girls. Though
females as found by Bishara and Jakobsen (1985). males show a somewhat more obvious increase in the second half
LFT - long face type of t h e i r teenage years, the values r e t u r n later almost to their
AFT - average face type original level. (From Bishara and Jakobsen, 1985; reprinted with
SFT - short face type. permission.)
66
Possibilities and Limitations of Variables and Analyses
Table 3.1 Cephalometric standard values for all variables of the presented analysis. The upper horizontal column is indicating the
respective age; the column on the very right gives the standar deviation. The first horizontal line is valid for males, the second for females.
(Forfurther details, see Zimmer and Miethke, 1989).
67
Orthodontic Cephalometry
W H Y USE CEPHALOGRAMS? patients are interested in their profile, i.e. in the
relative prominence of the maxilla (or, more pre
The answer to the question of why we use cephalo- cisely, of the upper lip as the representation of their
grams is probably that they enable the user to reach maxilla). Often, when the numbers gained by
a better diagnosis, which will in turn lead to more cephalometry do not correspond with clinical judge
comprehensive treatment of patients, with more ment, a correction of the original values according
stable results. In Western societies, comprehensive to the true vertical plane reveals much more mean
management includes aesthetics, and it is here that ingful results.
the true vertical correction of cephalometric mea
surements becomes most valuable. For example, A correction in relation to the true vertical has
cephalometric assessment may indicate that a one absolutely mandatory requirement: every
patient's maxilla is retruded while clinical evalua cephalogram has to be taken in natural head
tion gives a different impression (3.5). How can this position. If this was not accomplished, extraoral
happen? If, for instance, a patient has a skull con photographs that were taken in this surprisingly
figuration with a low-positioned sella, the reading reproducible head posture (Moorrees and Kean,
for the SNA angle will be small even if the maxilla 1958; Solow and Tallgren, 1971; Siersbaek-Nielsen
itself is correctly positioned in space. No patient is and Solow, 1982; Cooke and Wei, 1988a; Cooke,
interested in the position of his sella, but almost_all 1990) could be used for a subsequent reorientation
of a cephalogram according to the true vertical (Jost-
K.Nadine B K,Nadine
* 2412/975 KModine * 24121975
= 290V985 * 24.12.1975 = 29.0JM85
= 29.01)985
3.5 Natural head position and its in (B) The same tracing as in (A) with the (C) Obviously, in this patient the cant of
fluence on cephalometric analyses. (A) By Steiner analysis values. This data indicates, the anterior cranial base is remarkable (75,
simply looking at the tracing of this patient, for example, a retruded maxilla (SNA = standard value 85"). After correction in
one gets the impression of an almost 76) and mandible (SNB = 73 ) as well as a relation to the true vertical, the SNA now
normally positioned maxilla and mandible steep occlusal plane (24 , standard value measures 86°, SNB 83", and SN-OcP 14*,
with a more or less normal vertical facial 14°). which in our opinion is more in accordance
dimension. with the patient's actual appearance.
68
Possibilities and Limitations of Variables and Analyses
Brinkmann et al, 1989). Onlyjn natural head posi computer it corrects all linear measurements (e.g.
tion does a patient's a p p e t e n c e correspond to Wits appraisal, li-APog) to their original size. Thus,
reality, and the true vertical correction leads to more small errors due to image magnification - which will
reasonable cephalornctric readings (3.6). not affect angular measurements - can be compen
'Another important requirement is that all sated for. This is even more important for repetitive
cephalornctric X-rays should be taken with a mil assessments than for single ones, though it should
limeter scale (3,7). If this scale is read into the never be completely ignored.
3.6 Extraoral photographs of a patient w i t h her head slightly bent forward (A) and backward (C). Only with natural head position/
posture (B) does the profile assessment become definite.
3.7 If cephalograms are taken with a millimeter scale, as shown here,
even linear measurements from different X-rays can be compared
because a correction t o the original (natural) size becomes feasible. In
o u r analysis, this correction is automatically accomplished by EDP
69
Orthodontic Cephalometry
REFERENCE PLANES TRUE VERTICAL PLANE
The last problem that needs to be discussed before It was stated above that the problem of a constant
we will go into our specific analysis is which refer reference plane cannot be solved. This is not
ence plane or structure should a clinically mean absolutely correct. It can be solved if the true vejtical
ingful analysis be based on. The literature is full of plane is used. The true vertical plane is a constant
opposing statements. That is why the various ref and is perpendicular to the true horizontal, which
erence lines still compete with each other. It is also is a constant.. Some clinicians have acknowl
unlikely that this problem can be solved. One system edged this fact and developed a cephalornetric
is more or less as good or poor as any other, and assessment that is based on this reference plane
none is completely reliable because each is subject (Michiels and Tourne,J990; Viazis, 199J) (3.9).
ed to a large individual variability (3.8). What can However, the analysis of Michiels and Tourne only
be done to diminish this problem? The answer is to considers the spatial position of A, B, and Pog, and
choose measurements that are based on different ref furthermore it offers norms derived from only 13
erence planes; in this way it is hoped to compensate females; on the other hand, the problem with the
for pronounced variations in one or the other ref Viazis analysis is that it is based on the Bolton stan
erence lines, as if a measurement error is averaged. dards, in which natural head position was never a
3.8 Variation of SN and FH in patients with normal occlusions 3.9 Cephalornetric analysis by Viazis (1991) with ten variables.
from the Downs series; superimposition on the palatal plane based on the t r u e vertical w i t h respect t o the t r u e horizontal. Red
(ANS-PNS). (From Thurow, 1970; reprinted with permission.) lines indicate skeletal measurements, blue lines dental variables,
and green lines the t w o soft tissue parameters. (From Viazis, 1991;
reprinted with permission.)
70
Possibilities and Limitations of Variables and Analyses
serious consideration - in other words, the short SPECIFIC CONSIDERATIONS OF A
coming of the Viazis method is a lack of the equiv CEPHALOMETRIC ANALYSIS
alent norm data.
The analysis we feel comfortable with at present is
Almost the same is true for a summary five-factor divided into four fields or areas (3.11). These are:
cephalometric analysis described by Cooke and Wei • sagittal basal relationships;
[1988b) (3.10). The basis of this method is also • vertical basal relationships;
natural head position but instead of being related to • dentoalveolar relationships; and
the true vertical, it is related to the true horizontal • memos, i.e. important evaluations without proper
plane (HOR). The angles NA and NB to HOR are
determined in the same way by Lundstrom and measurements.
Lundstrom (1989), as is the position of the chin and
the upper and lower lip as well as the incisor appear As stated above, in cephalometric analyses the cal
ance by Bass (1987|. Finally, the analysis of Spradley culated data is compared with other data. This data
etal(198l) is limited only to soft tissue points in the for comparison can be called by a number of names
lower facial third; somewhat similar is the cephalo — ideals, optimals, averages, means, norms, stan
metric evaluation which was suggested by Lund dards. The answer as to which is the best term could
strom and Cooke (1991). take much space but would probably still not satisfy
everybody, as it is almost a philosophical problem.
3.10 Five-factor summary analysts as described by C o o k e and For the sake of simplicity, this data is here called
Wei (1988b). All measurements are based on the t r u e horizontal. 'standards', in the hope that this term is somewhat
This plane was demonstrated t o be six times less variable than any non-committal and that it leaves room for individ
intracranial reference. A r e q u i r e m e n t f o r this is, however, that ual interpretation according to one's standpoint.
every cephalogram be taken in natural head position. (From C o o k e
and Wei. 1988b; reprinted w i t h permission.) One could criticize us for relating a certain
variable to an author who did not describe it in the
first place. This may be correct, though in some
cases is it extremely difficult to identify the authen
tic originator. Therefore, we chose to ascribe every
assessment to the person with whom it is commonly
associated but who at the same time defined the
relevant reference points and planes most precisely
and gave the most thorough explanation of its
clinical importance.
A final criticism could be that readers do not
agree with some of the abbreviations selected
(SN-SGn instead of y-axis, etc.). We accept this crit
icism, though we made these choices to give our
analysis a certain homogeneity in its layout.
71
Orthodontic Cephalometry
Freie Universit&t Berlin
Fachbereich Zahn-, Mund- und Kieferheilkunde
Abt. fur Kieferorthopadie und Kinderzahnheilkunde
Cephalometric analysis
Name :
Birthday -
ID number : / Diff.
Variable: Stan TV 1.Ceph 2.Ceph 3.Ceph 4.Ceph Diff.
dard
FH-TV *
SN-TV 92°
85°
Sagittal basal relationships
SNA 82° *
SNB 79°
NPog-FH 83°
ANB
WITS 3°
NA-APog -1mm
N'Pm'-DtUl 3°
12°
vertical basal relationships
SN-SGn 66°
SN-NL 7°
SN-ML
ArGoMe 30°
SGorNMe
SN-OcP 124°
68%
14°
Dento-alveolar relationships
li-ML 96°
li-APog 2mm
li-ls
130°
Memo 4. Morphology of the mandible
1. Nasio labial angle 5. Tonsilia pharyngea
2. ls-lip line 6. Tonsillae palatinae
3. Palatal spongeous bone
3.1 I Form used for the analysis described in this chapter. The left upper corner shows personal data. The columns of the list contain
(left to right): the variable to be measured; the standard value for comparison; and the values that are corrected for the true vertical
(TV). These columns arc followed by those with the actual measurements ( I . Ceph, etc.) and the ones with the differences between any
two cephalograms (Diff)- The division of the form into four areas is clearly recognizable. (For further details, see text.)
72
Possibilities and Limitations of Variables and Analyses
ASSESSMENT OF SAGITTAL BASAL • actual reading < standard (eventually
RELATIONSHIPS (3.12) negative reading) - concave facial profile
(related to osseous structures), mesial relation
The following list consists of the parameters (abbre ship of mandible relative to maxilla.
viated) that are measured in the sagittal plane, the 7. N'Pm'—DtUl (Holdaway) — soft tissue convexi
persons to whom they are attributed, and the inter ty in relation to the projection of the most
pretation of the measurement results. The results are anterior part of the skull base onto the frontal
measured in millimeters for the Wits appraisal; the soft tissues and soft tissue promentale (g);
other results are angles, measured in degrees. All • actual reading > standard — convex (soft
values arc stated to one decimal place, which is tissue) facial profile, distal relationship of
almost more than adequate. Though every computer mandible relative to maxilla;
calculates easily up to eight digits, this is only fake • actual reading < standard (theoretically
precision because of the well-known limitations of negative reading) - concave (soft tissue) facial
the material (X-ray cephalograms) and the method profile (related to soft tissues), mesial relation
(evaluation of cephalograms) itself. ship of mandible relative to maxilla.
B. SNA (Steiner) - position of maxilla to skull First, it is obvious that this analysis is principally
base (a); based on very conventional measurements, which
• actual value < standard - retrognathic enhances communication. Further, it could be spec
maxilla; ulated that these measurements have some merits
• actual value > standard - prognathic maxilla. since they have been used for a long time.
1, SNB (Steiner) - position of mandible to skull Further, it is easy to reckon that the idea of dif
base (b); ferent reference planes was indeed realized: the
• actual value < standard - retrogenic Steiner angles are related to the SN plane, those of
mandible; Downs to the Frankfort Horizontal respectively to
• actual value > standard — progenic mandible. the anterior border of the skull base as well as to
3. NPog-FH (Downs) — position of mandible in each other (NA-APog), the Wits appraisal to the
relation to the Frankfort horizontal plane (c); occlusal plane, and the Holdaway soft tissue eval
• actual value < standard - retrogenic uation (like the NA-APog angle) to the extension of
the skull base onto the forehead, the chin, and the
mandible;
• actual value > standard - progenic mandible. upper lip.
4. ANB (Steiner) - relation of maxilla and Such cross-evaluation with different reference
mandible to each other (d); planes is important; this can be demonstrated with
• actual value > standard - distal relation of two examples:
mandible relative to maxilla; 1. If one takes only the ANB angle to measure the
relative position of maxilla and mandible to each
I • actual value < standard (eventually negative other, one must realize that any different hori
reading) - mesial relation of mandible relative zontal or vertical position of point N and the
to maxilla.
5. WITS (Jacobson) - relation of maxilla and location of the points A and B in the vertical
mandible to each other (e); plane will have an influence on the size of this
• actual reading > standard - distal relation of angle and not on the actual sagittal relation of the
mandible relative to maxilla; two jaws (Hussels and Nanda, 1984) (3.13). The
• actual reading < standard (eventually same holds true for a rotation of the occlusal
negative reading) - mesial relation of mandible plane: backward rotation of the occlusal plane
relative to maxilla. has a decreasing effect on the ANB angle,
6. NA-APog (Downs) - relation of maxilla and forward rotation has an increasing effect on the
mandible to each other as well as to the most ANB angle, though the sagittal basal relation
anterior part of the skull base (f); ships remain constant. Since the weakness of this
• actual reading > standard - convex facial measurement is known by many prudent ortho
profile (related to osseous structures), distal rela dontists, there have been attempts to individu
tionship of mandible relative to maxilla; alize the ANB angle, thus making it more
73
Orthodontic Cepbalometry
74
Possibilities and Limitations of Variables and Analyses
3.13 Schematic drawing of the effect on the A N B angle if a
certain parameter is changed while the others are held constant:
forward or backward rotation of the occlusal plane (A), vertical
difference in height of point A (B), vertical variation of point N (C),
and deviation in horizontal position of point N (D). (From Hussels
and Nanda,l984; reprinted with permission.)
B
*•
N N'
Variable Standard Patient I Patient II Patient III Patient IV
Angle Clas I HI ill 1
ANB angle (°) 7.8 1.0 0.9 -0.5
Wits appraisal (mm) 1.4 - 8 . 1 - 6 . 5 2.4
SN-ML 0 44.5 42.3 41.0 25.5
|SG:NMe(%) 57.1 62.6 58.7 70.4
' NL-ML 0 24.0 34.0 31.0 31.8 24.8
SN-OcP (°) 13.5 23.9 22.4 22.8 9.4
i
Table 3.2 List of four patients who in a study on this subject were found to have the largest ANB-Wits appraisal differences (with adult
unisex standards for comparison). It becomes obvious that these patients had either a Class III malocclusion (patients II and III) or
demonstrated a pronounced vertical deviation (being excessive in patients I to III and deficient in patient IV). Patient I was. despite her
nije ANB angle, considered Class I (with an open bite). In general, the Wits appraisal agreed more with the clinical classification.
75
Orthodontic Cepbalometry
independent of variations that are not directly severe vertical discrepancies (Table 3.2). There
connected to the sagittal jaw relationship fore, it is reasonable to assess the sagittal jaw base
(Kirchner and Williams, 1993). Panagiotidis and relationship with measurements that are based on
Witt (1977) give an example of this approach. different reference planes. Further, it is important
They recommend the calculation of the repre to look with special care at those patients where
sentative ANB angle hy the formula -35.16 + 0.4 there are contradictory results in the anteropos-
(SNA) + 0.2 (ML-SN). The only problem with terior jaw relation.
this procedure is that it is not very easy to use and Above all, it is important to make the final decision
it is therefore n o t likely to be regularly used by about the existing sagittal basal problem after a
clinicians. t h o r o u g h clinical e x a m i n a t i o n . This advice is in
2 . If, for instance, t h e ANB angle a n d the Wits accordance with that of Bittner and Pancherz
appraisal both measured the true relative sagittal (1990), who stated that 'sagittal and vertical dental
relationship of the mandible to the maxilla, their and skeletal intermaxillary malrelationships (as
correlation coefficient should be 1.0. In their detected on cephalograms) were only partly reflect
study, Miethke and Heyn (1987) found that this ed in the face' (3.14). However, facial appearance is
correlation in fact varies between 0.24 and 0.85 what most patients are really interested in.
with an average of 0.8. This means that after a The angle of facial convexity and the soft tissue
simple statistical rule of t h u m b barely t w o thirds profile evaluation d o not seem very meaningful to
of the variations are explained by the t w o vari us any more. The N'Pm'-DtUl angle is recorded
ables; the rest is due to chance. In the same study, mainly so t h a t o u r analysis c o n t a i n s at least one
it also became obvious that these t w o measure measurement related to soft tissue. But both mea
ments were most contradictory in patients with surements are, according to o u r very personal ex
severe skeletal problems. This was mainly due to perience, on the verge of being omitted.
No. % S A G I T T A L JAW BASE RELATIONSHIP
(ANB-Angla|
ao
60 _ Validity
ED v * « - v »^l
E3 h i g h
«»o -
20 _
Clas
11
3.14 In this study by Bittner and Pancherz (1990), the validity of the sagittal basal relationship was assessed when seven investigators
inspected photographs of 172 children. It becomes obvious that only patients w i t h a Class II anomaly are easily detected. The failure race
in patients with a Class I o r a Class III malocclusion is high. (From Bittner and Pancherz, 1990; reprinted w i t h permission.)
76
Possibilities and Limitations of Variables and Analyses
ASSESSMENT OF VERTICAL BASAL • actual value > standard - increased (lower
RELATIONSHIPS (3.15) anterior) vertical facial height.
12. SGo: NMe (Jarabak) - ratio of posterior to
The vertical evaluation consists of the following anterior facial height (m:m');
measurements, again — as above - with its originator • actual value < standard - increased total
Jmd its interpretation; the measurements are anterior vertical facial height;
percentages for the faciaJ height index; all the others • actual value > standard - decreased total
are angles given in degrees: anterior vertical facial configuration.
8. SN-SGn (Brodie) - chin position in relation to 13. SN—OcP (Steiner) - cant of occlusal plane to
skull base (h); skull base (n);
• actual value < standard - decreased vertical • actual value < standard - decreased vertical
facial height; dentoalveolar dimension;
• actual value > standard - increased vertical • actual value > standard - increased vertical
facial height. dentoalveolar dimension.
. SN-NL (Hasund et al) - cant of maxilla to skull
base (i); The last measurement is not strictly a skeletal mea
• actual value < standard - decreased upper surement. It is related to occlusion and would there
facial height; fore be better listed as a dentoalveolar assessment.
• actual value > standard - increased upper However, as aU the other tooth-reVated measure
facial height. ments are purely sagittal, it seemed more logical to
10. SN-ML (Hasund et al) - cant of lower border add it at the very end of the vertical parameters.
of mandible to skull base (k); Again it can be noted that the different measure
• actual value < standard - decreased vertical ments depend on various references. Four of them
facial height; are based on the SN plane (SN-SGn, SN-NL,
• actual value > standard — increased vertical SN-ML, and SN-OcP), whereas the other two have
facial height. a relation in itself- the gonial angle in the mandible,
11. Ar-Go-Me (Bjork) - angle between ramus and the facial ratio in the general vertical structure of the
corpus mandibulae (1); face.
• actual value < standard - decreased (lower We have often found- and probably this experi
anterior) vertical facial height; ence is shared by many clinicians - that one specific
3.15 All vertical basal and dentoalveo
lar parameters measured. For abbrevia
tions the readers are referred to the
text.
77
Orthodontic Cepbalometry
assessment of a patient will indicate deficient vertical Basically it can be solved by not paying too much
skull architecture while another assessment will attention to any particular measurement, but instead
point in the opposite direction. For instance, Duter- finding out about the general trend of the vertical
loo et al (1985) make a distinction between skulls skull structure. This can be accomplished in differ
with a small and a large divergency (3.16). However, ent ways. The simpliest is to overview all numeri
the most hypodivergent skull (Skull 1) demonstrat cal values and re-evaluate them as a whole. Another
ed a larger angle SBa-NL than the most hyperdi- way is to have a graphical presentation as in the
vergent skull (Skull 2). What can be a solution to polygon devised by Vorhies and Adams (1951). One
this dilemma? critical look at this will show whether the vertical
3.16 Though in an investigation by D u t e r l o o et al (1985), Skull I
(A) was characterized as having a relatively small divergency, it
demonstrated a larger SBa-NL angle than Skull 2 (B), which was
considered t o have a relatively large divergency. (From Duterloo et
al, 1985; reprinted with permission.)
78
Possibilities and Limitations of Variables and Analyses
values tend to be more on one 'shoulder1 or the other. most objective method of describing the overall sev
The best approach is probably to establish an overall erity of a patient's vertical problem. The only dis
vertical index. The original idea for such a summary advantage of this procedure is that it takes more time
assessment seems to go back to Schopf (1982) (3.17) and effort than an average evaluation and, therefore,
and was further developed by us (Heyn, 1986). As will probably not be accepted for regular use by the
seen in Table 3.3, a particular vertical measurement majority of clinical orthodontists. An evaluation
is credited with a certain value, which can be positive index could also advantageously be developed for
or negative depending which vertical extreme it is the assessment of the sagittal basal relationship in
tending towards. The resulting value may well be the cephalograms.
3.17 Graph (redrawn) developed by
Schopf (1982) to assess the general ver
tical facial configuration. In this particular
patient, four out of six parameters are in
dicating an above-average facial structure.
le 3.3 Evaluation list in which every measurement is credited with a certain number (rating) to assess the overall vertical basal
duration of an individual patient. Plus and minus values will either balance or enforce each other. This approach dates back to 1986, a
wat which we still used the sum angle (NSBaGoMe) of Bjork, which we have subsequently stopped using.
79
Orthodontic Cepkalometry
GROWTH PREDICTIONS called a prediction, though a more apt term might
be 'guessing'. This is especially valid if such a
Up to here, the term 'growth' has not been used in forecast is founded just on clinical experience.
this representation.The reason is twofold: The outcome may be more reliable if it results
1. Often cephalograms are taken in adults where the from a very large computer data base, though
even in such cases doubts are advisable
term in its original meaning cannot be applied, (Greenbcrg and Johnston, 1975; Witt and Koran,
even though up-to-date information confirms 1982). In a revealing study, Baumrind et al (1984)
that growth almost never ceases completely, as demonstrated that vertical growth prediction was
already stated above. not better than chance even when performed by
2. It seems very dubious to make a statement about presumably very experienced clinicians with a
growth, which is a four-dimensional process mean duration in clinical practice of 28 years.
(sagittal-vertical-transverse change over time) on A growth prediction with a certain clinical impact
the basis of a two-dimensional image, especially is feasible, however, when two cephalograms with
since it excludes time, the most important para a due time interval are taken from the same patient.
meter. To make a statement about the further Then the development in sagittal and vertical dimen-
development of an anatomical entity is often
3.18 Superimposition on the areas of the cranial floor, which are 3.19 In this eight-year-old patient, the occipital part of the head
marked by red lines, according to Steuer (1972) and Riedel (1972). cannot be seen, so no statement about her cephalic type is
In this girl, the maxilla between the age 12 and 13 has grown possible. Even if her nose tip were right next to the right margin o(
slightly mesial and remarkably caudal. Since the mandible is the film, it would still be doubtful if the patient's whole head would
influenced by the maxillary growth and translation as well as by its have been imaged. What is described here is even truer for adults.
dentoalveolar changes, no information can be gained directly about
the predominant mandibular growth direction. Overall, this patient i
obviously shows a rather vertical growth pattern. The vertical lines
indicated by the arrow do not belong to the cranial base but are
the wings of the sphenoid bone. Because of their distinct vertical
course, they definitely help to orientate the two tracing on each
other.
80
Possibilities and Limitations of Variables and Analyses
sion can be evaluated either by comparing respec fulness. However, our favourite vertical assessments
tive (numerical) values or graphically by superim- are the facial ratio and the gonial angle. Both seem
position (3.18). Again, some scepticism is to have the highest practical importance. They
warranted, since there is no guarantee that a specific appear to err less than other values, and a possible
growth direction is valid during the whole devel explanation is:
opmental process. The work of Linder-Aronson et • the facial ratio depends not on three reference
Jal (1986) in particular has proved that in some points but on four. It is possible that the inclusion
patients vertical growth can change - either diminish of one more anatomical structure lessens the like
or increase. Nonetheless, most patients follow their lihood of a deviation that is derived by chance.
original growth path. Furthermore, the linear measurements of the pos
However, the only absolutely correct growth terior and the anterior facial height actually take
evaluation remains a retrospective one. Because of place in the vertical plane.
the above-mentioned possible complications, we • the gonial angle is related to the mandible, a
have decided not to use the term 'growth'. Instead, structure that contributes remarkably to the
| we use terms such as face or skull structure or con vertical growth process. An anatomical compo
figuration, because these descriptions are more nent such as this is a more sensible parameter
neutral and thus more relevant. than structures that depend on the anterior
For a similar reason we stay away from the cranial base (SN), which is located far away from
expressions brachycephalic and dolichocephalic. the (lower) visceral skull. This is in keeping with
Originally these anthropological terms included the Ricketts (1972), who recommends reliance on the
(overall skull depth (anteroposterior dimension), mandibular arc (angle) (3.20). The only objection
.which is almost never imaged in an average cephalo- to this angle is that point Xi is much more diffi
jgram (3.19). Furthermore, a brachycephalic or cult to determine (Miethke, 1989).
(dolichocephalic characterization has to include an
(evaluation of skull width (frontal plane), which is We are often asked why the Bjork sum angle is not
[impossible to deduce from a standard cephalomet- used in our analysis. The answer is quite simple: the
ric X-rav. sum angle equals the angle SN-ML adding 360°
As noted above, some of the sagittal basal rela (Reck and Miethke, 1991) (3.21). Thus, by mea
tionships have lost for us some of their previous use suring SN-ML, we indirectly included the Bjork
sum angle in our analysis.
s^ N
^?o[y —^
H- »
*ViV-
<^x^\
n\" ^ ^ tt
Go ^ t t , ) II 0°
Me
3.20 The mandibular arc (angle) is based 3.21 Schematic drawing of the geometric relation between the angle SN-ML and the
on the reference points DC, Po (PM), and sum angle of Bjork (Jarabak). (For further details, see Reck and Miethke, 1991.)
I Xi. The accuracy and reproducibility of the
bst point in particular is very low. (Redrawn
(from Ricketts, 1972.)
81
Orthodontic Cephalometry
ASSESSMENT OF DENTOALVEOLAR T h e first aspect that becomes obvious is that this
RELATIONSHIPS (see 3.15) part of our analysis is extremely short. However,
there is nothing w r o n g with this - if shortness were
Our cephalometric evaluation of the dentition an indication of concentration, it would be advan
involves only the following three measurements tageous. Tweed's original analysis (1969) consisted
(abbreviations, originators, and interpretations as also of only three measurements (3.22). Was it there
above): fore worse than other analyses? Were treatments
14. li—Ml, (Downs) - axial inclination of lower based on this analysis inferior or less stable - if the
analysis was used with a critical mind? We feel that
incisors in relation to mandibular plane (o); the measurements listed above are, in general, suf
• actual value < standard - retroinclination of ficient. Again - as mentioned previously - there is
incisors in the mandible; ample space at the end of this part of our analysis
• actual value > standard - proclination of w h e r e further parameters could be added if felt
incisors in the mandible. appropriate.
15. li-APog (McNamara) - position of lower
incisors relative to anterior border of maxilla Also it will be noticed that the evaluation of the
and mandible (p); incisors in the mandible is in the centre of attention.
• actual value < standard - retroposition of This seems to be reasonable, since modern ortho
mandibular incisors; dontics focuses on this criterion (Miethke and
• actual value > standard - anteroposition of Behm-Menthel, 1988).
mandibular incisors.
16. l i - l s (Downs) - axial inclination of lower and Again, there a r e two reference planes that are
upper incisors to each other (q); independent of each other:
• actual value < standard - protruded position • the mandibular plane and
of upper and lower incisors to each other; • the plane that describes the anterior border of
• actual value > standard - retruded position of
upper and lower incisors to each other. both jaws (A-Pog plane).
3.22 The Tweed analysis originally inclu
ded only these three measurements. It is
o b v i o u s l y c e n t r e d a r o u n d t w o highly
c r i t i c a l p a r a m e t e r s : the p o s i t i o n of the
mandibular incisors (over basal bone), and
t h e angle F M A , w h i c h r e p r e s e n t s the
(anterior) vertical dimension of the maxilla
and the m a n d i b l e . ( F r o m T w e e d , 1969;
reprinted with permission.)
82
Possibilities and Limitations of Variables and Analyses
Additionally the angular and the linear measure panoramic X-ray can easily fulfil the same purpose,
ment are thought to 'control' one another. as one can see the posterior border of the mandibu-
lar and maxillary dentition (ramus ascendens and
The inclination of the maxillary incisors can maxillary tuberosity) as well as one can on a head-
easily be assessed indirectly through the interincisal plate (3.24).
angle, and their position can be assessed indirectly
through the overjet (3.23). Finally, one may criticize on the basis that all den-
toalveolar assessments are purely sagittal. However,
The measurements consider only anterior and not this is not really true, since the cant of the occlusal
sterior teeth because we feel that the anterior plane (to SN) is giving us a sufficient indication of
the overall situation of the teeth and the alveolar
ent of the dentition is much more critical as far processes in the vertical plane.
ssuccess and stability of orthodontic treatment is
concerned. However, there is nothing wrong with
an evaluation of the molar position. Besides, any
3.23 In this patient with a Class II Division 2 malocclusion, the
M—ML angle amounts t o 91.9" (age- and sex-corrected standard
92.0"). The interincisal angle totals 159.8" (compared to standard
130.0"); there is no overjet. Consequently, the position and
inclination of the maxillary incisors can be indirectly assessed as
palatally inclined and located.
3.24 Orthopantomogram of a 15-year-old female. There seems 53 B
j to be sufficient space according t o the patient's age f o r the third
! molars to erupt later (A). This impression is confirmed on clinical 83
examination (B). There is extra space distal t o the second molars,
! whidi is seen better on the right than o n the left side (owing t o
nrror position).
Orthodontic Cephalometry
NON-METRIC ASSESSMENTS OF THE 17. Nasiolabial angle - angle between columella
SKULL AND SOME SURROUNDING and philtrum of upper lip.
ANATOMICAL UNITS
Ideally this angle should be 90° to 100° (Brown and
At this point the metric evaluation of cephalograms McDowell, 1951). This angle is age-dependent; it is
in our analysis is concluded. Nevertheless, it would small in very young children (87.5° in newborns)
not be appropriately complete without the follow (3.25) and increases remarkably in teenagers
ing observations. They are listed under the headline (111.5°), getting only slightly bigger in twenties
'Memo', which implies that they should not be over (112° on the average) (Miethke, 198Q) (3.26). This
looked even if they are not measured in degrees and means that there is a difference between the average
millimetres or calculated in percentages. So the of our population and the ideal. Expert texts
topics (17-22) listed below have to be checked off continue to explain that even a nasiolabial angle of
either taking a mental note or adding a free formu 120° can be acceptable; for instance, Brown and
lated text: McDowell (1951) state that this can look 4piquante'
in some faces.
B
3.25 Average (B) as well as minimum (A) and maximum (C) nasiolabial angle in newborns.
A BC
3.26 Average (B) as well as minimum (A) and maximum (C) nasiolabial angle in adults (dental students).
84
Possibilities and Limitations of Variables and Analyses
Overall, the message is that if this angle is initially than average skull configuration, and the higher
small, the facial balance could be improved by ratio (three quarters) in patients with a more pro
choosing a treatment approach that would increase nounced decrease in facial height. We do this
it (Lo and Hunter, 1982). On the other hand, if the because lip length is almost impossible to alter, and
nasiolabial angle is large in the beginning, treatment a necessary vertical change in the incisor position is
should not aim to increase it. often compromising the patient's appearance.
Ir is beyond the scope of this text to go into For example, patients with an excessive vertical
skull structure often have a very minor overbite,
Idetails about whether extractions of maxillary teeth sometimes a manifestly open bite. At the same time
have an influence on this angle. There are doubts_as their upper lips (if not both lips) are short, so that
to whether the angle can be influenced by orthp- these patients tend to have a 'gummy' smile (3.28).
clontic means atone (Paquette et al, 1992; "Young A relative intrusion of the upper incisors, which
and SmithJ_993) but there can be no doubt that would bring them into a favourable alignment with
orthognathic surgery (combined with orthodontic the upper lip, would worsen the overbite situation.
treatment) is able to alter it. The only solution in these cases is to intrude these
Finally, age (see above) and also a patient's sex teeth just as much as necessary (the two thirds goal)
(females often prefer to have fuller lips than males) and establish a good, functioning overbite (with an
should never be overlooked when a particular nasi incisor guidance) by rotating the whole lower dental
olabial angle is considered as a support for a specific arch counterclockwise, and to supplement this with
therapeutic approach. some extrusion of the anterior mandibular teeth.
18. Is - lip line - relation of the most caudal part of Any orthodontist should realize at this point this
the upper lip to the labial surface of the maxil true dilemma. Let us describe it with another
lary (central) incisors. example. A patient whose skull structure is lower
than average is prone to have a deep bite and rather
Probably it is a somewhat fruitless discussion long lips. The first treatment option, therefore, is to
whether the relaxed upper lip should cover three extrude the posterior teeth, thus indirectly opening
quarters or two thirds of the upper anteriors or leave the bite and 'shortening* the lips. Many eminent
about a 2-mm 'show', as stated by different ortho orthodontists object strongly to this approach
dontists (Arnett and Bergman^JSSS) (3.27). Our because they claim that such an extrusion is not
point of view is that it should be within this range. feasible in that it is very likely to relapse because the
For practical purposes, we take the lower value (two facial musculature works against any vertical
thirds) into consideration in patients with a higher increase, whether in growing children or in adults.
I
3.27 Attractive tooth/lip line relationship with the lips slightly
apart.
$5
Orthodontic Cephalometry
Therefore, they demand to solve the existing deep trading good morphology against a good smile
bite problem by an intrusion of the incisors. But do (3.29) because, if the anterior teeth are hidden behind
they consider what happens to the tooth-lipline rela- the lips, a patient gets the 'disastrous' appearance of
tionship at the same time? Acting this way means an old person (Perkins and Stale_y,J_993).
3.28 (A) Eight-year-old patient with a short upper lip and a eruption of posterior teeth, intrude her upper anterior teeth in
considerable 'gummy' smile. (B) Although, this patient demon- harmony with her lip length, and establish sufficient overbite by a
strates hardly any overbite, it would be, aesthetically, completely counterclockwise rotation of her mandible supplemented possibly
unacceptable t o deepen her bite by (maxillary) incisor extrusion. with minor extrusion of her lower incisors.
Instead, every effort should be made to control the patient's
3.29 Even when this patient gives a full smile, very little of his r a t h e r long lips, giving him an unpleasing, almost senile look.
maxillary anterior teeth shows (A). A t the same time this patient Instead, everything should be attempted t o open his deep bite
exhibits a deep bite which should not be corrected by intrusion of i n d i r e c t l y by an increase in v e r t i c a l d i m e n s i o n (extrusion of
the incisors (B). This would make his teeth disappear behind his posterior teeth).
86
Possibilities and Limitations of Variables and Analyses
The author of this text does not have the final tively, the ultrasonographycally measured mor
solution to this problem. However, if one believes it phology of the masseter muscle and a specific
is possible to influence 'growth1, would it then be vertical skull configuration (Ruf, 1993).
completely absurd to include muscles as well as
bone? If we take adaptation into account could this Overall, the relationship of the (maxillary) incisors
not even occur to a certain degree in adult patients? to the (upper) lipline should be evaluated, even if the
How do many experienced maxillofacial surgeons clinical consequences are not easy to solve.
approach the problem of a vertical facial deficien-
I a and a deep bite? Do they not also increase the 19. Palatal spongeous bone - cancellous bone
posterior vertical dimension? Even if, in all these cir behind the maxillary incisors.
cumstances, some relapse evolves, at least this could
be considered as a compromise between the optimal Many orthodontists agree that teeth should only be
moved through spongeous bone. Many feel that if
t and the possible. Furthermore, it should be pointed teeth contact cortical bone either root resorption or
out that a recent doctoral thesis has failed to prove a perforation of the bony cortex (or both) may be
[adistinct correlation between EMG activity respec the result (Ten Hoeve and Mulie, 1976) (3.30).
3.30 Example to demonstrate the rela
tion between the amount of palatal bone
and possible root resorption. (A) Cephalo-
gram of a patient in w h o m maximum
retraction of the incisors was planned. The
incisors are located directly anterior to the
palatal cortical plate. (B) A superimposition
on the maxilla shows that the front teeth
were distalized without any intrusion. The
tracing from the treatment result (broken
lines) implies that the incisors are almost
within the cortical bone. (C) Periapical
radiographs of (right) maxillary incisors at
the beginning of treatment. (D) The same
t e e t h as in (C) at the end of r e t r a c t i o n
therapy. Probably because these teeth have
contacted the cortex of the hard palate,
some remarkable apical r o o t resorption
has occurred.
(Courtesy of D r L Alverado de Scholz.)
87
Orthodontic Cephalometry
Therefore, the amount of spongeous bone that is mum distalization of the anterior dental segment is
palatal to the maxillary incisors determines the required (so-called maximum anchorage cases) but
amount they can be ideally retracted. Admittedly in whom the amount of spongeous bone behind the
this information can also be gained by a model incisors is not adequate? John H. Hickham taught
analysis, but only partially. The slope of the anterior us to answer the previous question with these
part of the palate is often simply a reflection of the words: 'You have to get them up to get them back'
incisor inclination, although the amount of (Hickham, 1978). Every intrusion brings the
spongeous bone that is palatal to the incisors varies incisors into a position where more spongeous bone
from patient to patient, even among patients with for tooth movements is available (3.32).
an identical incisor position. Therefore, varying
amounts of complication-free retraction are feasible Even if there is only limited scientific proof, it
(3.31). What about those patients in whom maxi- seems that one contributory factor for root resorp-
tion is too intimate a contact between the (palatal)
E, Bettina
* 26.02MB
— WJ2.1985
- 1109.1986
2-3
3.31 Midsagittal sections through models of different patients.
Although the incisor inclination does not vary remarkably, there
are obvious differences in the spaces behind their roots. It is
impossible to state which of these spaces are occupied by the
gingival tissue o r h o w thick the palatal c o r t i c a l plate is in any
individual patient. Even so, this may prove that, w i t h the same
t o o t h position, the slope of the palate varies, as does the amount
of spongeous bone behind the maxillary anterior teeth.
3.32 Adult patient with maximum anchorage requirements at the
beginning of treatment. Although some mesial molar movement
has o c c u r r e d , the incisors have obviously been retracted (and
uprighted). The distalization did not result in any root resorption,
though the cortex of the palate was adjacent t o the incisor roots.
W e believe that this uneventful retrusion was only feasible because
it was accompanied by an intrusive component.
SK
Possibilities and Limitations of Variables and Analyses
cortex and the roots of the respective teeth demonstrate certain peculiarities in the morphology
(Wehrbein et al, 1990). Therefore, it should be of their mandibles, as well as their whole skulls
decided if a maximum retrusion of the incisors can (3.33). Since these peculiarities remain after puberty,
be attempted, and if so, how it can best be accom they can be distinguished in adults as well as children.
plished. The cephalogram will give valuable hints Why worry about the vertical dimension in
for the solution of this critical clinical problem. adults, where growth will not change it any more?
This concern seems indicated since any therapy with
20. Morphology of the mandible - typical structural extrusive components will have much more exten
features of the lower jaw. sive consequences in patients with vertical excess.
Their bite opens sometimes very fast, followed by a
Through his classical implant studies, Bjork (1969) tongue position between upper and lower incisors
found that patients with different vertical growth which again has a negative effect on the overbite
•3 ♦2 ♦1 -1 3.33 The morphological characteristics of
the mandible that are supposed to indicate
predominant growth direction (skull
configuration). (A) The shape of the
condylar process and the course of the
mandibular canal are rated with a number
between +3 or -3 depending on which
extreme they are tending to. Left
-3 horizontal, right vertical growth (skull
configuration), (B) The arrows point to
areas of the mandible with pronounced
bone apposition (+) or resorption (-), and
respective thickness of bone tissue. Left
horizontal, right vertical growth (skull
configuration). (After Segner and Hasund,
1991; reprinted with permission.)
89
Orthodontic Cephalometry
(3.34). In short, this can easily become the begin • allergic rhinitis/nasal hyperactivity; and
ning of a vicious circle. That is why attention has to • chronic rhinosinusitis.
be paid to the vertical skull configuration, even in
adults. T h e o r d e r of frequency varies depending on envi
r o n m e n t a l and other general conditions, and it
Bjork's structural analysis can be used to evaluate varies according to a patient's age; however, one or
a patient's cephalogram and it is just another more of these four aspects is usually the cause.
attempt to make double sure and triple safe not to
miss a patient's vertical problem. Under this premise, it makes sense to evaluate the
size and formation of the tonsilla pharyngea, which
21. Tonsilla pharyngea - size of pharyngeal can be well distinguished on a lateral cephalogram
adenoids relative to upper airway diameter. (3.35). It is not safe to assume, however, that there
is an airflow inhibition if the area between the
Only few orthodontists and scientists doubt that a d e n o i d s and the soft palate is n a r r o w e d . This is
there is a cause-effect relationship between mouth because t h a t the cephalogram provides a two-
breathing and the vertical development of the skull, dimensional view of a three-dimensional anatomi
the face and the dentition (CKRyan et al, 1982; Vig, cal structure, in which only these surfaces that are
1991), whereas the majority of clinicians and tangentially hit by the X-rays are imaged - mostly
researchers believe that they have good proof that those structures in the midsagittal plane. This means
this relationship exists (for example, Linder- t h a t the adenoid masses to both sides of the
Aronson, 1970; Woodside et al, 1991). With this midplane can be much smaller than they appear on
relationship in mind, it is worth remembering that a cephalogram, and thus they can compensate for
the four most important reasons for inhibited nasal apparent constriction. This is one reason why we do
breathing are: not measure any distance in this area numerically,
• enlarged pharyngeal (and eventually palatal) as other analyses recommend. Nevertheless, we feel
that this assessment has the same importance to us
tonsiLs; as if we evaluated it quantitatively.
• deviations of the nasal septum;
3.34 A 32-year-old patient w i t h m i n o r o v e r b i t e w h o seeked
o r t h o d o n t i c t r e a t m e n t f o r cross-bite c o r r e c t i o n of upper left
lateral incisor (A). She presented w i t h an additional cross-bite of
the right first molars and a moderate curve of Spee (B). Mainly
because of levelling with extrusive mechanics and also because o1
some c o r r e c t i o n of the lateral cross-bite, the anterior overbite
changed t o an open bite. Though not completely contraindicated
(because the upper left lateral incisor has t o be moved labially) it
will be difficult t o close the bite again. It is easy t o imagine that
now a tongue interposition exists (C).
90
Possibilities and Limitations of Variables and Analyses
Any patient in whom an obstruction of the upper cephalograms and a reasonable referral policy
nasal airways is suspected (whether from clinical should be practised.
inspection or radiography) should be referred to an
ENT specialist w h o can ascertain w h e t h e r or not 22. Tonsillae palatinae - estimated size of palatal
such an obstruction is present. tonsils.
It is often best to approach E N T colleagues with Finally, the palatal tonsils should be evaluated.
questions that require exact answers a b o u t the Although the palatal tonsils seldom obstruct the
existing airflow condition (Jonas and M a n n , 1988; airway (the main exception being the clinical con
Zimmerand Miethke, 1989). This approach almost dition described as 'kissing tonsils', in which grossly
always results in a written reply that satisfies us and enlarged tonsils almost meet in the middle of the
that can be kept in the patient's records. oropharynx), they can, even under less extreme cir
cumstances, inhibit breathing during sleep (sleep
Even if the influence of adenoids on the breath apnoea) (3.36). Much has been written recently
ing mode is not yet absolutely clarified and even if about this condition, and it is a problem that can
the definition of mouth a n d nasal breathing may be have serious consequences to health (Knobber and
very difficult to accomplish with scientific precision, Rose, 1985; Potsic and Wetmore, 1990).
; we feel it is our duty as dental surgeons t o follow all
traces which may be unfavourable for the develop Nocturnal breathing obstruction is one reason for
ment of our patients. Even if inhibited nasal breath inspecting the tonsils on cephalograms. Another
ing does not influence the n o r m a l g r o w t h of the reason is that hypcrplastic lymphatic tissue in this
orofacial structures, we still strongly believe that it area occupies space that actually should be filled by
has an impact on the general development of a child. the posterior part of the tongue. This can lead to an
Therefore, adenoid size should be checked in
3.36 Enlarged tonsillae palatinae with typical signs of (chronic)
inflammation in an 11-year-old boy. Although these tonsils do not
inhibit his breathing during the day. it was considered that they
were the cause of his sleep apnoea.
JJ5 Eight-year-old patient w i t h obviously enlarged adenoids
(verified by ENT specialist). Although her lips are closed o n this
rephalogram, they are m o r e o f t e n apart. T h e r e f o r e , she was
considered a mouthbreather. H e r vertical skull configuration is
somewhat excessive (e.g. large gonial angle), but her overbite is
Kill sufficient.
91
Orthodontic Cephalometry
altered tongue position and function. A more wall. McNamara states that a distance up to 14 mm
forward position or an anterior function of the is normal, but that anything above this might be the
tongue is often related to the development or pro result of oversized tonsils if the measurement has not
gression of a Class III malocclusion or an open bite been falsified by tongue movements (as happens, for
(Fischer and Miethke, 1988) (3.37). Studies have instance, during swallowing).
suggested that this deviation from normal is one
factor that causes relapse after a correction of the This is not the only problem in assessing the size
anomalies mentioned above (Grunert and Krenkel, of the tonsils. Another is that the palatal tonsils can
1991), although no sound scientific proof is yet almost never be seen directly on a cephalogram
available. because of their indistinct structure. Instead of mea
suring the tonsillae palatinae, cephalograms in fact
The idea of assessing the size of the palatal tonsils measure the amount that the radix of the tongue is
is not new. Several clinicians and researchers have displaced from where it is believed it should be.
suggested a great number of measurements for this Because of these problems, it is probably more rea
purpose (for example Bergland, 1963; Linder- sonable to leave the evaluation of tonsil size to a
Aronson, 1970). One of the latest, best-known common sense clinical guess.
approaches is that suggested by McNamara and
Brudon (1993). It is advocated to measure the Therefore, even if the size of the tonsillae palati
distance between the intersection of the inferior nae is stated in the cephalogram report, it is worth
border of the mandible with the dorsum of the correlating this result with the clinical evaluation,
tongue to the closest point of the posterior pharynx especially in patients who have sleeping disorders
and a tendency towards a Class III or an open bite.
3.37 Eight-year-old boy with a Class III and an open bite; ANB =
2,5", Wits appraisal = -5 mm. The typically enlarged tonsils are
depicted with a broken line. The distance between the dorsal
pharynx wall and the intersection of the tongue with the lower
border of the mandible amounts to 16 mm.
92
Possibilities and Limitations of Variables and Analyses
GRAPHICAL REPRESENTATION OF or in patients who undergo orrhognathic surgery
NUMERICAL FINDINGS IN therapy as well as orthodontic treatment. In the
CEPHALOMETRY first case, however, we can practically never be
sure how much of the skeletal change should be
The idea of presenting the numerical findings of a attributed to our treatment and how much t o
cephalometric analysis in a graphical formula has independent growth.
long been advocated (Vorhies and Adams, 1951),
We feel rhat such a graphical representation has A graphical representation is shown in 3.38. The
several advantages: graph is automatically plotted as soon as the numer
1. Intellectual abilities of individual practitioners are ical data is calculated. For repeated analyses the
different. Some prefer a more abstract and theo same document can be fed into the plotter again.
retical approach, while others prefer a more Critical readers now may ask the questions: Why
concrete, practical approach. Some orthodontists so much fuss? What is characteristic of the 'wiggle-
can be fully informed by looking at the measure gram' you have developed? At the beginning of the
ments that result from their analysis, whereas form, the name, date of birth, and code number of
others find it quicker and easier when the mea the patient is found. The graph, by means of spaces,
surements are expressed graphically. reflects the separation of the different fields
Despite the fact that some orthodontists may (sagittal-basal, vertical—basal, and dentoalveolar
prefer a graphical presentation of cephalometric relationships). The internal structure of the graph is
data, every orthodontist is able to follow a such that the spaces between all values of each mea
numerical analysis. This is not the case, however, surement are very specific. Thus it is guaranteed in
with experts from other medical specialities, and an adult patient (15 years and over) that:
their understanding of the problems revealed by • all standards will form a straight vertical line in
a cephalometric analysis is remarkably improved the centre of the representation; and
by a graphical representation. • the double plus and minus standard deviation is
I. This aspect becomes even more important when represented by two dotted straight lines on either
lay persons - patients and their parents, relatives, side of the standard.
and friends - are confronted with a cephalomet
ric analysis. A numerical analysis is almost never The standard value is always marked individually
comprehensible to people who have not been by the plotter with a small black cross. This value
medically trained. Even if they cannot fully depends on the patient's age and sex. If the patient
understand a graphic representation of the same is not yet fully grown (as conventionally defined)
analysis, they will certainly be able to get a better this cross will be (slightly) off centre.
understanding of the situation. This better under The lines that represent the twofold standard
standing will produce a patient or parent who is deviation are not always absolutely straight vertical
much more our ally than enemy. Some prerequi lines, as this is also age- and sex-dependent.
sites must be fulfilled to accomplish this better However, their deviation from ideal straight lines
understanding, and these are described at the end is usually hard to reckon. In any case, the ±2
of this list. standard deviation field includes all cephalometric
■(.Possibly the most important reason to have access values that can be defined as physiological (i.e.
i to a graphical representation of the cephalomet- normal).
Iricanalysis is that, by studying it carefully, one If the standard is in the middle and the two outer
becomes more self-critical and modest. This is lines mark the normal variation the lay person better
true under the condition that the graph of our understands how far away the patient in question is
. analysis shows the results of repeated cephalo- from the ideal, where the specific problems are, and
grams at the same scale. Most probably one will why these require a certain treatment procedure.
| recognize from this that there are very little The same holds true of course to a varying degree
changes in all the skeletal parameters and at best for non-orthodontic medical specialists.
I some remaxkabie differences .;.v fita isfewdjrJ cAvrr- Tite orthodontist WI'IY see wi'tn one glance even
Iacteristics. Real, dramatic changes of skeletal more. From the organization of the individual mea
measurements can only be found in growing surements all values that indicate a Class II (sagittal
basal assessment,) and open bite tendency (vertical
—
93
Orthodontic Cephalometry
Frele Unlvorsitit Berlin Name: S, V; m
Fachborolch Zahn-,Mund-und Kt o f o r h e i l k u n d o
flbt. f u r K l e f o r o r t h o p a d l o u n d K 1 n d o r z ahnho 1 I k u n d o ID-No.: /
Birthday: 05. 12.64
Graph ic r e p r e s e n t a t ion of cephalometrfc analysis
SNR
SNB
NPog-FH
RNB
WITS
NR-RPog
N'Pm'-DtUl
SN-SGn
SN-NL
SN-ML
RrGoMe
SGo:NMe
SN-OcP
I i -ML 130 12B IBB.9 . 100
1i-RPog IB
li-ls LIB X \ -2,1
SB 6.i ; B
1 9.B 147.4
*5 •Jl 1 !■•• 150
112.1 ■ 30 MB"
.-1 i 1
1GB 17B
Ceph 1 f r o m 2 9 . B 6 . B 7 , age 22 y e a r s
3.38 Graphic representation of the cephalometric analysis described in the t e x t A l l necessary personal data is listed at the upper right
corner. In the lower left corner, it is stated when different cephalograms were taken, and how old the patient was each time. "Hie
numbers below each horizontal graph indicate the scale. The numbers above the graphs in the centre reflect the standard values. The
numbers left and right of the dotted vertical lines represent the values of the plus o r minus twofold standard deviation. The data shown
here was derived from a patient with an ideal occlusion and a normal extraoral feature. Surprisingly o r not, all parameters apart from
NPog-FH are very close to their respective standards.
94
Possibilities and Limitations of Variables and Analyses
Frele Unlversitat Berlin Name: M.r F . ; m
F»chboro1ch Zihn-,Mund-und K t d e r n e ( I k u n d o
Rbt. f u r K i o f o r o r t h o p a d l e und K l n d « r z a h n h a I 1kundo ID-No.: /
Birthday: 01.06.77
Graphic r e p r e s e n t a t i o n of cephalometr1c a n a l y s i s
SNA
SNB
NPog-FH
RNB
WITS
NR-flPog
N'Pm'-DtLM
SN-SGn
SN-NL
SN-ML
RrGoMe
SGo:NMe
SN-OcP
li-ML
li-flPog
H-ls
Coph 1 f r o m 1 2 . 0 7 . B 9 , age 12 y e a r s
]U9 Typical graphical representation of cephalometric data from a 12-year-old male patient with a Class II Division I malocdusion that
■aggravated by an open bite. The curve that connects all individual values is strictly on the left side. It sometimes even crosses over the
unfold standard deviation (dotted) line.
95
Orthodontic Cephalometry
Frele Universitht Berlin Name: R. , B. ; ui
Fachborolch Zahn- , Mund-und K i ef orho 1 1 kunde
R b t . tQr K i a f a r o p t h o p l d t o und Kinderzahnhe11kunde ID-No.: /"
Birthday: 12.03.79
Graphic representation of cephalometr i c analys is
SNR
SNB
NPog-FH
RNB
WITS
NR-RPog
N'Pm'-DtUl
SN-SGn
SN-NL
SN-ML
RrGoMe
SGorNMo
SN-OcP
1 I -ML
1i-RPog
li-ls
Ceph 1 f r o m 1 8 . 0 4 . 3 2 , age 13 y e a r s
3.40 Graphical representation of cephalometric analysis of a 13-year-old female. The patient was diagnosed to have a Class III anomaly
with a negative overjet. The vertical basal relationship was decreased. Upper and lower incisors were lingually inclined. Again with one
glance the patients main problems become evident.
96
Possibilities and Limitations of Variables and Analyses
basal assessment) with a proclination of the incisors One reason not to use this graphic representation
will result in a line off-centre to the left (3.39). Class as a routine form is that, unfortunately, the mesh
III patients with a tendency to deep bite and very diagram is difficult to produce. It takes time and
upright incisors are indicated by an off-centre line skill to come up with an acceptable result. Part of
to the right (3.40). Surprisingly or not, many the difficulty is due to the fact that not every square
patients fit quire well in one of the two above men of the mesh contains a reference point (Landau et
tioned categories. Of course in Class II division 2 al, 1988). This means that the anatomical structures
patients the curve will swing after the sagittal basal in such a square have to be connected to squares
field from the left side to the right and remain there. that contain a reference point by free-hand drawing.
Curves that result from cephalograms taken at The more important reason not to use the
different times can be colour coded. Moorrees mesh routinely is that we became acquaint
ed with the Jacobson templates, and we feel that for
our purposes these can replace the mesh analysis.
The Jacobson templates are tracings to scale of
NON-NUMERICAL individuals with ideal occlusions and a pleasing
CEPHALOMETRIC ANALYSES appearance (3.42). All one has to do is to superim
pose the appropriate template on the actual tracing
There have long been approaches aimed at making or even the original X-ray image of a specific
an individual's morphological deviations from the patient. This superimposition takes place in the
norm even more visual by an adequate distortion of nasion-sella—basion triangle. On the nasion-basion
the patient's actual cephalometric tracing (Moorrees plane, a perpendicular line through the sella is con
1953,1991) (3.41). structed, and this line bisected; the resulting mark is
iC-.«fi«B)
PROPORTiONATI
TEMPLATE
J.4I Moorrees mesh analysis of a patient with a mucolipidosis III 3.42 Jacobson proportionate template of a small white
[diagnosis not verified): Class II sagittal-basal relationship with an (Caucasian series) person with normal occlusion and pleasing
| unproportional face height probably due t o a deficient posterior aesthetics. ( F r o m Jacobson, Proportionate Templates, Nola
facial length. Maxillary hypoplasia, remarkable bimaxillary Orthodontic Specialities; reprinted with permission.)
protrusion, steep inclination of the anterior cranial base and spatial
decrease between (posterior) nasal floor and basis cranii. Since in
the Moorrees analysis the profile is t o the left, it is oriented here
MM same way. The drawing on the lower right side indicates the
rectangle size; solid lines indicate original mesh size, broken lines
ndicate individual patient's size.
97
Orthodontic Cephalometry
the starting point of the superimposition (3.43). This Differences also exist between various popula
midpoint is used mainly to average the error that tions, and this is why Jacobson developed additional
might be the consequence of a deviation in one of templates for American blacks. Differences that are
the three planes in the patient who is to be due to age and sex are reflected by a series of tem
compared with the standard. Beside this basic super- plates for children and adolescents (3,44). This
imposition, many others are feasible (Bench, 1972); series is to be used with common sense because head
e.g. on the maxilla and the mandible to find out size can vary widely within one age group. If an
about the dentoalveolar situation, on the soft tissue extremely small or large patient is compared with
to assess it. The Jacobson template analysis is com an age-matched template of average skull size, gross
mercially available and comes with an extensive deviations would be indicated everywhere, devia
description of how to use it. tions that in reality do not exist. To compensate for
this type of error, it is necessary to use a template of
It seems to be a problem to superimpose a an older or younger child with a head size that
template on different patients because the head size matches the patient being examined. The compari
varies remarkably. However, this is not a structur son will then lack some accuracy, but if this analysis
al problem but one of proportional enlargement or is used with critical common sense it can yield useful
diminution. Therefore the templates come in four results.
sizes (small, average, large, and extra large). The
first step of its user is to find the template that fits Besides this restriction we feel that the Jacobson
best. This is done principally by comparing the template analysis is very advantageous for beginners
nasion-basion base line. Then the two other planes in the field of cephalometry, for communication
(NS and SBa) are included in this process of com with maxillofacial surgeons, for communication
parison until the template in which the anterior skull with patients, and even for experienced clinicians to
base corresponds optimally with that of our partic get an immediate overview about the major problem
ular patient is found. of a patient.
3.43 Superimposition of Jacobson template and individual tracing
(X-ray). First, NBa are aligned, then the template is moved up o r
down keeping NBa parallel until the mid S-J points (see 3.42) of
the tracing (X-ray) and the template are at the same level. (After
Jacobson, Proportionate Templates, Nola Orthodontic Specialities;
reprinted with permission.)
3.44 Jacobson proportionate template of a 10-year-old boy with
normal occlusion and favourable facial features. (After Jacobson,
Proportionate Templates, Nola Orthodontic Specialities; reprinted with
permission.)
98
Possibilities and Limitations of Variables and Analyses
CONCLUSION • have obviously escaped the general attention so
far, since they are seldom quoted elsewhere;
The primary intention of this chapter has not been > are relatively new and can serve well as a starting
to convince readers that our analysis is the optimal point for an extensive investigation of the litera
one, but to make the reader more critical of what he ture;
has done so far. We know which the best analysis * a personal affection to - mostly articles with the
for us at this time is, but we do not know which the present author as the (co)author.
best cephalomctric analysis in absolute terms is.
However, we are convinced that there are aspects
(hat characterize a cephalometric analysis that is Arnett GW, Bergman RT (1993) Facial keys to
superior to others. orthodontic diagnosis and treatment planning - part
A cephalometric analysis with a reasonable II. Am} OrthodDentofacial Orthop 103:395-41 1.
clinical base should:
• use reference points that are clearly defined and Bass NM (1987) Bass orthopedic appliance system.
easy to locate; Part 2. Diagnosis and appliance prescription. J Clin
• rely on more than one bone reference plane, since Orthod 21:312-20.
these planes are themselves variables;
• consider natural head position because resulting Baumrind S, Korn EL, West EE (1984) Prediction of
values then often reflect the actual appearance of mandibular rotation: An empirical test of clinical
the patient better; performance. Am J Orthod 86:371-85.
be clearly structured in skeletal and dentoalveo-
lar assessments and always distinguish between Behrents RB (1989) The consequences of adult cran-
the different planes (sagittal, vertical, transverse); iofacial growth. In: Orthodontics in an Aging
include as few measurements as possible, so that Society. Carlson DS (ed). Monograph 22.
an optimal overview is maintained at any time; Craniofacial Growth Series. (Center for Human
include a graphic representation, which is useful Growth and Development, The University of
for immediate understanding and which enhances Michigan, Ann Arbor.)
communication with non-orthodontic colleagues
and with patients; and Bench RW (1972) Seven-position serial cephalo
■ • be structured so that it can be changed without metric appraisal of normal growth and/or treatment.
difficulty when better insight requires an adap Proceedings. (Foundation for Orthodontic
tation. Research): 137-61.
ww?ith rhis in mind, our very final advice is to use the Bergland O (1963) The bony nasopharynx. Acta
>halometric analysis our readers have selected as Odontol Scand 21(suppl 35).
[thebest onc(s) with critical distance, common sense,
Bishara SE, Jakobsen JR (1985) Longitudinal
and experience. Or, as the teachers of the author of changes in three normal facial types. Am j Orthod
this textbook chapter put it in a very short and 88:466-502.
drastic form: You cannot go by numbers!
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99
Orthodontic Cephalometry
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Downs WB (1952) The role of cephalometrics in
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100
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