Canted occlusal plane ; etiology and evaluation part 1

Canted occlusal plane ;etiology
and evaluation
part 1
Dr Maher fouda
Professor of orthodontics
Mansoura Egypt

Turkish J Orthod Vol 27, No 4, 2015
Reference:

Frontal occlusal plane
The frontal occlusal plane
is represented by a line
running from the tip of
the right canine to the tip
of the left canine. A
transverse cant can be
caused by the differential
eruption of the maxillary
anterior teeth or a
skeletal asymmetry of
the mandible.

The most important
esthetic goal in
orthodontics is to
achieve a ‘‘balanced’’
smile, which can be
best described as an
appropriate
positioning of the
teeth and gingival
scaffold within the
dynamic display
zone.

The display zone
are affected by
the size, shape,
position, and
color of the
displayed teeth
as well as the
gingival contour,
buccal corridor,
and framing of
the lips.
Smile components

The Eight Components of a Balanced Smile
ROY SABRI, DDS, MS ©2005 JCO, Inc.
1. Lip Line
Upper Lip Length
Lip Elevation
Vertical Maxillary Height
Crown Height
Vertical Dental Height
Incisor Inclination
2. Smile Arc
Overintrusion of Maxillary Incisors
Cant of the Occlusal Plane
3. Upper Lip Curvature
4. Lateral Negative Space

ROY SABRI, DDS, MS ©2005 JCO, Inc.
5. Smile Symmetry
6. Frontal Occlusal Plane
7. Dental Components
8. Gingival Components

Cant of the Occlusal Plane:
Extraoral forces,
intermaxillary elastics, and
orthognathic surgery can
affect the cant of the
occlusal plane. If the
maxillary occlusal plane is
canted upward anteriorly,
for instance, the incisal
edges will move away from
the lower lip, resulting in a
nonconsonant smile arc .
Consonant (a) and non-consonant arc of
the smile (b), determined by the upper
incisal line and the internal surface of
the lower lip

Conversely, if the occlusal plane has an
excessive clockwise tilt, the upper incisal
edges will be covered by the lower lip, making
the smile arc less attractive

Retracted
Close Up
Teeth Apart.
Note the Rise and
Cant in the Incisal
plane up to her
right side.

Other factors that can affect
the smile arc are attrition due
to shortening of the central
incisors, habits such as
thumbsucking, excessive
posterior vertical growth
(mostly seen in brachyfacial
patterns), and the lower lip
musculature.
Consonant and nonconsonant
smiles: A , consonant smile with
parallelism between the curvature
of the maxillary incisal edge and
the upper border of lower lip; B ,
nonconsonant smile, with no
parallelism between the curves.

Intraoral
frontal view
depicting
asymmetric
open bite due
to long
persistent
unilateral digit
sucking habit.

Maxillary incisor inclination
affects not only the lip line,
but the smile arc as well,
when the curvature of the
incisal edges does not
coincide with the border of
the lower lip in smiling . Lip line with reduced
incisor display due to
proclined maxillary incisors.

Excessively proclined
incisors will be
associated with an
everted lower lip,
whereas uprighted or
retroclined incisors
will be partially
covered by the lower
lip.

Patient with
canted occlusal
frontal plane
and unilateral
posterior
gingival smile.

ROY SABRI, DDS, MS
©2005 JCO, Inc.
6. Frontal Occlusal Plane:
Patient with canted occlusal frontal plane
and unilateral posterior gingival smile.
This relationship
of the maxilla to
the smile cannot
be seen on
intraoral images
or study casts, and
smile photographs
can also be
misleading.

ROY SABRI, DDS, MS
©2005 JCO, Inc.
6. Frontal Occlusal Plane:
Patient with
canted occlusal
frontal plane
and unilateral
posterior
gingival smile.
Therefore, clinical
examination and
digital video
documentation
are essential in
making a
differential
diagnosis between
smile asymmetry,
a canted occlusal
plane, and facial
asymmetry.
Smile
asymmetry
associated
with smile
limitation
facial asymmetry
to the left with a
vertical
component,
canting the
occlusal plane to
the right

ROY SABRI, DDS, MS
©2005 JCO, Inc.
6. Frontal Occlusal Plane
Having the patient bite on
a tongue blade or a mouth
mirror in the premolar
area during the clinical
examination is a good way
to recognize an
asymmetrical cant of the
maxillary frontal occlusal
plane.

Smile design and
mechanotherapy
must take into
account an
esthetic plane of
occlusion, which is
often different
from the natural
plane of
occlusion.
A. Patient with
asymmetrical
cant of
maxillary
anterior
transverse
occlusal plane.
B. Different
bracket height
on maxillary left
canine vs.
maxillary right
canine. C.
Patient after
treatment.
occlusal cant (OC) in the frontal plane .

esthetic plane of
occlusion,
The average point of
contact between
maxillary and mandibular
first molars and the upper
lip stomion is taken as a
reference. Then a line is
drawn between these two
points to determine the
FAOP

Occlusal Plane :The
occlusal plane (OP)
is an imaginary
surface that is
anatomically related
to the cranium.
Theoretically, it
touches the incisal
edges of the incisors
and the tips of the
occluding surfaces
of the posterior
teeth.

Therefore, the OP is the plane that
would be established if a line were
drawn through all the buccal cusp tips
and incisal edges of the mandibular
teeth and then broadened into a
plane to include the lingual cusp tips,
continuing across the arch to include
the buccal and lingual cusp tips of the
opposite side.
The OP is not, in fact, a plane, but
rather represents the mean
curvature of this surface.

Because most jaw movements
are complex, with the centers of
rotation constantly shifting, a
flat occlusal plane will not
permit simultaneous functional
contact in more than one area of
the dental arch. The curvature
of the occlusal plane is
primarily a result of the fact
that the teeth are positioned in
the arches at varying degrees of
inclination

The OP of the
dental arches is
curved in a manner
that permits maximal
utilization of the tooth
contacts during
chewing. This
curvature of the dental
arches has been
referred to as the
curve of Spee.

A second curve associated
with the OP can be
observed from a frontal
view and is called the curve
of Wilson..
Curve of Wilson: The
natural curvature of the
occlusal plane of the
molar and premolar teeth
in the coronal plane

In cephalometric
radiographs (in the
sagittal plane), the OP
is defined as a line that
joins the midpoint of
the overlap of the
mesiobuccal cusp of
the first molar and the
incisal edges of the
incisors.

In posteroanterior
(PA) radiographs
(in the vertical
plane), the OP is
defined as a line
that joins the
buccal cusps of the
right and left
upper first molars
in a transversal
direction

The OP adapts
to the
alterations
that occur
with age,
vertebral
maturation,
and changes in
dental
position.

Lateral cephalometric
studies evaluating the OP in
a sagittal direction indicated
that the inclination of the
OP alters according to
changes in craniofacial
structures during
craniofacial growth and
development.Schudy stated
that condylar growth (as
related to vertical growth) is
the key to changes in the OP.

In the frontal
plane, changes
in the OP result
from posterior
rotation and
relocation of the
maxilla and
mandible in a
vertical
direction.
Illustrations of subjects in A, the ipsilateral group, with the
frontal occlusal plane inclined toward the ipsilateral side of
the mandibular deviation; and B, the contralateral group,
with the frontal occlusal plane inclined toward the
contralateral side of the mandibular deviation. Midline, CG-
ANS; FOP, the line joining the bilateral maxillary first molars

The inclination of the
OP increases in a
clockwise direction
during growth.
Symmetric growth
and development
enables the
conservation of the
angles between the
cranial planes and OP
during an increase in
vertical dimensions.

Although changes
in the inclination
of the OP in the
sagittal plane are
associated with
growth and
development.

Changes in the
inclination of the OP in
the vertical plane
result from asymmetric
growth of the
craniofacial structures
and lead to an
asymmetric OP; this is
defined as OC.
Canted maxillary anterior
occlusal plane.

Occlusal Cant : Occlusal
plane canting in the
vertical plane is one of
the parameters affecting
smile esthetics and
originates from facial
asymmetry and/or
vertical position
asymmetry of the right
and/or left quadrants of
the dental arches
without facial
asymmetry.
Facial asymmetry
and
hemimandibular
hyperplasia
vertical position
asymmetry of the right
and/or left quadrants of
the dental arches
without facial
asymmetry.

A 38-year-old woman
sought orthodontic
evaluation with concerns
about missing teeth, an
unesthetic anterior
dentition, prominent lower
incisors and protrusive lips.
There was no contributing
medical history, but she
had a long history of
limited, restorative dental
care.

Extra-oral evaluation with the
lips closed showed a
symmetric bimaxillary
protrusion with coincident
dental and facial midlines.
Upon smiling her dentition
was unattractive due to an
end-to-end incisal relationship,
occlusal cant (more inferior on
the right side), irregular
spacing in the anterior
segments, and intermaxillary
midline diastemas.

Occlusal Cant : Occlusal
cant is frequently
associated with facial
asymmetry; the
reported frequency
of facial asymmetry
in cases involving this
condition varies
between 21% and
80%.
Non-surgical Correction of Craniofacial
Microsomia with Occlusal Plane Canting

This wide range
may result from
differences
between reports
in characteristics
of facial
deformity, types
of skeletal
malocclusion,
age, or ethnicity.

In addition, observed
differences in the
proportion of facial
asymmetry in OC
may be due to
variations in
methods, symmetry
criteria, or
measurement
sensitivity between
studies.
facial and intraoral
photographs. A, Pretreatment;
B, presurgery; C, postsurgery

Good et al indicated that
the incidence of
asymmetry increases in
patients with skeletal
class III malocclusion and
increased lower facial
height. According to
Severt and Proffit,OC is
found in 41% of patients
with class III
malocclusion.

Symmetry and
Asymmetry
Perception: It has
been
demonstrated
that symmetric
faces are more
attractive but
not more so than
less symmetric
faces.
Is a Symmetrical Face the
Key to Attractiveness?

Symmetry and
Asymmetry Perception:
However, preferences for
symmetry cannot solely
explain the attractiveness
of average faces. Usually,
symmetric faces are
preferred by individuals;
however, a person’s
preference for symmetry
was not correlated with
their ability to detect it. Symmetry

Photo of smile modified to create occlusal canting of 2º
Photo of smile with 0º occlusal canting.
The perception of
OC varies between
lay persons, general
dentists, and
orthodontists.
Oliveres et al
concluded that an
OC of 2 degrees
was acceptable to
lay persons,
general dentists,
and orthodontists.

Photo of smile with 0º occlusal canting.
In addition, lay persons
and general dentists
found OC more
acceptable than
orthodontists. Lay
persons failed to detect
the existence of an OC
reaching 3–4 degrees .
Padwa et al concluded
that 4 degrees is the
threshold for detection
of OC.

Etiologic Factors in
Asymmetry and Occlusal
Cant :Determination of
asymmetries and
classification of cases is
complicated by the
multifactorial nature of
asymmetry. The etiology
of asymmetry can be
classified as consisting of
hereditary and
environmental factors.

The patient was a 19-year-old. Her
chief complaint was anterior open
bite and discrepancy of the midlines
between the maxillary and
mandibular arches. She was not
aware of her facial asymmetry and
was not dissatisfied with or
concerned about it. There was no
history of trauma to her head or jaw.
The family history was not relevant,
and the cause of her facial
asymmetry was unknown. In the
frontal view, the mandible was
slightly deviated to the left, and the
lip line was canted.

In the lateral view, the facial profile was
straight, with upper and lower lip
protrusion. The discrepancy between the
maxillary and mandibular midlines was
4.0 mm, with the maxillary incisors inclined
to the left and the mandibular incisors
inclined to the right. Overbite and overjet
were −2.0 and 4.0 mm, respectively. The
occlusal plane was canted and almost
parallel to the line passing through the left
and right corners of the mouth. The
anterior open bite extended from the left
first premolar to the right first premolar.
The molar relationships were Class III on
the right and Class I on the left. There was
no crossbite or scissorsbite in the
posterior teeth, except in the right first
premolar region

Etiologic Factors in
Asymmetry and Occlusal
Cant: Cleft lip and
palate,hemifacial
microsomia, juvenile
idiopathic arthritis, Treacher
Collins syndrome, Albright
syndrome, Apert syndrome,
Crouzon syndrome, and
craniosynostosis are the
common hereditary factors
that lead to facial
asymmetry and OC.
Treacher Collins Syndrome

Hemifacial microsomia is a congenital condition in which the tissues on one
side of the face are underdeveloped. It primarily affects the ear, mouth and
jaw areas, though it may also involve the eye, cheek, neck and other parts
of the skull, as well as nerves and soft tissue

The most important clinical
findings in hemifacial
microsomia are mandibular
malformation with facial
asymmetry and microtia.
Hypoplasia of the soft
tissues, orbital
involvement, nerve
disorders, and other
affected anatomic
structures are present
with a wide range of
variations
Microtia is a congenital deformity where
the pinna (external ear) is underdeveloped

Her extraoral examiation
revealed no significant
facial asymmetry. The
upper dental midline was
coincident with the facial
midline. There was an
occlusal cant in the maxilla.
Her profile view showed
flat paranasal areas and
slight midfacial retrusion
with a straight facial profile
Repaired Cleft lip and palate:

Mandibular condylar hypoplasia is
facial deformity caused by a short
mandibular ramus.

(A) Patient with (juvenile
idiopathic arthritis )JIA of
the left
temporomandibular joint.
The lack of dentoalveolar
development of the
affected side results in
dental compensations
and an oblique occlusal
plane. (B) Occlusion of
the unaffected side and
(C) of the affected side.
Early Orthopedic Treatment and Mandibular Growth of
Children with Temporomandibular Joint Abnormalities
Seminars in Orthodontics, Vol 17, No 3 (September),
2011: pp 235-245

An Algorithm for Management of Dentofacial Deformity
Resulting From Juvenile Idiopathic Arthritis: Results of a
Multinational Consensus Conference
Resnick et al. Management Algorithm for JIA Dentofacial
Deformity. J Oral Maxillofac Surg 2019
The temporomandibular joints (TMJs)
are affected in most patients with
juvenile idiopathic arthritis (JIA), the
most common chronic pediatric
rheumatologic condition. In rare cases,
TMJ arthritis may be the presenting or
only feature of JIA.The TMJ is unique in
that it contains the primary
mandibular growth site just below a
thin layer of fibrocartilage. As a result,
synovitis caused by JIA may lead to
both osseous degeneration and
restriction of condylar growth

Environmental factors
affecting facial asymmetry
and OC include facial
trauma and fractures
(prenatal and postnatal),
jaw cysts, and facial
tumors as well as their
surgical treatment,
teratogens, hormonal
disorders (such as
gigantism or acromegaly),
Romberg syndrome,
posture.
Acromegaly in an orthodontic patient
American Journal of Orthodontics and Dentofacial
Orthopedics Volume 130, Number 3

Environmental
factors affecting
facial asymmetry and
OC include
temporomandibular
joint (TMJ) ankylosis,
muscular disorders,
abnormal mouth
breathing, habits
such as finger or lip
sucking,

Environmental factors
affecting facial
asymmetry and OC
include long term bottle
or pacifier use, pencil
biting and nail biting,
tooth extraction and
carries, and incorrect use
of force during
orthodontic treatment or
when using midline
elastics.
Upper incisors are canted
descending from right to left
due to pen chewing habit.
Non-surgical orthodontic
treatment of anterior open
bite in an adult patient.
White life design – Case
presentation

Evaluation of Occlusal Cant
Occlusal cant is related to
the pattern of skeletal
and/or dentoalveolar
development and can be
classified with or without
facial asymmetry due to
asymmetric development of
the mandible, unilateral
extruded molars, or
asymmetric dentoalveolar
development.

Results of finger sucking. Asymmetrical left
side open bite and overjet
unilateral extruded upper molars
(C–E)
asymmetric
mandibular
jaw growth;

Evaluation of
Occlusal Cant:
Patients with OC are
evaluated by clinical
assessment, frontal
photographs,
cephalometry, and
3-dimensional
imaging methods

Pretreatment
smile
photographs
Submental view
photograph
Occlusal plane
canting

Pretreatment
cephalogram
Pre treatment OPG
Pre Treatment PA
cephalogram

Pre treatment volumetric CT scan

During clinical
assessment, a
tongue blade is
placed across
both first molars
to evaluate the
existence and
degree of
inclination of OC.

c) The occlusal plane is oblique in the
same direction as the maxillary and
mandibular planes

b) The positioning of
the Fox plane plate on
the superior arch shows
the maxillary plane
parallel to the bi-
pupillary line with an
interincisal midline shift
to the left. The flat
positioning of the plate
on the inferior arch
shows a significant cant
of the mandibular
plane.
Fox plane plate

3D
analysis
with Treil.
Evaluation of
Occlusal Cant

Recently, the
number of
patients
referred to
orthodontic
clinics as a
result of TMJ
disorders has
been
increasing.
His chief complaints
were clicking sounds
in the TMJ and facial
asymmetry with
mandiubular
deviation.

In patients with
unilateral TMJ disorder,
facial asymmetry is less
associated with occlusal
discrepancy; however,
canting of the OP in
these patients is
increased because of
mandibular hypoplasia
on the affected side.
Condylar hyperplasia
Condylar
hyperplasi
a (mandibu
lar hyperpl
asia) is
over-
enlargeme
nt of the
mandible
bone in the
skull

Differential Diagnosis
and Treatment of
Condylar Hyperplasia
JCO/JANUARY 2019
The patient had
experienced a fall
from stairs when he
was 7 years old, but
reported no visible
injury or treatment
at that time
Tc scan indication of a
hyperactive condyle
on the left side.

This young adult patient
presented with recent
onset right mandibular
growth and change in
occlusion. A technetium
scan revealed right
condylar hyperplasia
resulting in progressive
facial asymmetry.

Detailed clinical
examination
and radiological
evaluation of
the TMJ are
essential in
such patients
with TMJ
disorders
OPENING AND
CLOSING OF MOUTH
Teeth normally close
symmetrically, the jaw
is normally centered
ALIGNMENT
OF TEETH
Note cross
bite, under or
over bit

RANGE OF MOTION
measure from top
tooth edge to bottom
tooth edge .Opening
and closing of mouth
Normal opening ~ 40-
50 mm Functional
opening or necessary
for most dental
procedures ~ 36 mm
or at least 2 knuckles
between teeth
The knuckles are
the joints of
the fingers

SYMMETRY OF FACIAL STRUCTURES
Eyes, nose, mouth, length of mandible
POSTURE
Forward head posture,
rounded shoulders and
scapular protraction is
common

BREATHING
PATTERN
mouth
breathing,
short upper
lip

TONGUE OR
LIP
FRENULUM
RESTRICTION

LISTENING
FOR JOINT
NOISES,
CLICKS,
POPS OR
CREPITUS

PROTRUSION OF
MANDIBLE
Normal ~ 10 mm •
Lateral deviation of
mandible Normal ~
10 mm • Note
asymmetrical
movements,
snapping, clicking,
popping or jumps

RECORD DEVIATIONS
Lateral movements with
return to midline. The
opening pathway is
altered but returns to
midline, usually
indicative of a disc
displacement WITH
reduction or could be
neuromuscular
dysfunction

RECORD DEFLECTIONS
Lateral movements
without return to
midline.
Deflections are usually
associated with Disc
Dislocations without
reduction or a unilateral
muscle restriction.

CRANIAL
LOADING OF
MANDIBLE
PROVIDES
ADDITIONAL
VALUABLE
INFORMATION
PROM: apply
overpressure at
the end range of
AROM to assess
end feel

STRENGTH
Assess
muscles of
mastication,
deep cervical
flexors and
scapular
stabilizers

Temporomandibular joint imaging: current clinical
applications, biochemical comparison with the
intervertebral disc and knee meniscus, and
opportunities for advancement
Skeletal Radiol (2020) 49:1183–1193
16-year-old female with
normal TMJ. Sagittal (a)
and coronal (b) non-
contrast CT images in
bone windows
demonstrate a normal
temporomandibular
joint. Note the normal
joint space. A, articular
tubercle; B, mandibular
(or glenoid) fossa; C,
external auditory canal;
D, mandibular condyle

Temporomandibular joint imaging: current clinical
applications, biochemical comparison with the intervertebral
disc and knee meniscus, and opportunities for advancement
Skeletal Radiol (2020) 49:1183–1193
30-year-old female with normal TMJ. Sagittal
proton densityweighted non-contrast MR
images demonstrate a normal
temporomandibular joint with normal
positioning of the anterior and posterior bands
of the articular disc (white arrows) and normal
positioning of the mandibular condyle (black
arrows) in the close-mouth (a) and open-
mouth (b) positions

Panoramic TMJ
radiographs consisting of
the combination of the
frontal and lateral
projections for each TMJ
at the maximally open
jaw position. TMJ:
temporomandibular
joint. LatTMJ: panoramic
projection, lateral view
of the TMJ. FrnTMJ:
panoramic projection,
frontal view of the TMJ.
Diagnostic accuracy and reliability of panoramic
temporomandibular joint (TMJ) radiography to detect
bony lesions in patients with TMJ osteoarthritis

Example of the four types of
radiographic images in a patient
with TMJ osteoarthritis. Erosion
and osteophyte lesions are
noted on the articular surface
of the mandibular condyle.
PanRad: panoramic
radiography. LatTMJ: panoramic
projection, lateral view of the
TMJ. FrnTMJ: panoramic
projection, frontal view of the
TMJ. CBCT: cone-beam
computed tomography. 3D:
three-dimensional
reconstruction.

Posteroanterior
radiography is also
necessary in the
evaluation and
objective
measurement of OC.
Analysis of PA
radiographs allows
easy visual comparison
of asymmetry.

The most commonly used asymmetry
analyses are Grummons frontal
analysis and Sassouni analysis. These
analyses demonstrate the parallelism
and asymmetry of facial points and
planes according to predetermined
planes.

The horizontal
distance from the
menton to the
midsagittal plane
on PA radiographs
is measured as
deviation. The
angle of the OP to
the true horizontal
plane is measured
as the angle of OC.

The angle of
the OP to the
true
horizontal
plane is
measured as
the angle of
OC.

It has been demonstrated
that the degree of OC
relative to the true
horizontal plane as
measured
cephalometrically in the
frontal plane is equal to the
linear millimeter difference
between the right and left
medial canthus and the
right and left canine tips.

. Measurement of occlusal cant in the maxilla.
A, The magnitude of occlusal cant by
measuring the degree of canting relative to the
true horizontal. The reference lines for
determining the cant are as follows: a true
horizontal represented by a tangent to the
normal supraorbital rims (1) and a vertical line
drawn through the crista galli and upper third
of the nasal septum (2). The degree of cant is
determined with respect to the true horizontal.
On this AP cephalogram, the degree of canting
of the occlusal plane was 6 degrees. B, The
magnitude of occlusal cant can be measured by
evaluating the medial canthus-canine distance.
In the patient above, the medial canthus to
right canine distance was 62 mm; the distance
to the left canine was 56 mm, for a total
vertical discrepancy of 6 mm.

However, the
effectiveness
of PA
radiographs
may be
reduced by
head rotation
or improper
landmark
identification.

In the presence of
asymmetry,
basilar/submentovertex
(SMV) radiographs are
also useful.
(a-b) Anatomic landmarks and reference planes used in submentovertex cephalometric
analysis (Tracing 1). TPA, transporionic axis: line passing through the left and right tip of ear
rods corresponding to the line passing through the midpoint of external auditory meatus (LM,
left Mei; RM, right Mei); MP, midsagittal axis: perpendicular bisecting TPA; RCoL, right
condylion lateralis: most lateral aspect of right condyle; RCoM, condylion medialis: most
medial aspect of right condyle; LCoL, left condylion lateralis: most lateral aspect of left
condyle; LCoM, left condylion medialis: most medial aspect of left condyle; RCoL-MP, right
condylion lateralis-midline: distance from right L-point to MP; RCoM-MP: right condylion
medialis-midline: distance from right M-point to MP; LCoL-MP, left condylion lateralis-midline:
distance from left L-point to MP; LCoM-MP, left condylion medialis-midline: distance from left
M-point to MP

The SMV radiographs can
be used to diagnose dental
arch deviations resulting
from midline shifts,
craniofacial asymmetry,
condylar position in
functional mandibular
deviation, mandible
asymmetry, and, in
particular, maxillary
asymmetry in cleft lip and
palate patients.

The SMV radiographs
allow the assessment
of asymmetry within
each component part
of the craniofacial
complex as well as the
relative relationship of
these parts to one
another. In addition,
SMV radiographs are
less vulnerable to head
rotation.

Orthopantomograms
provide information
about mandibular
asymmetry. Habets et
al described condylar
height symmetry
calculated by condylar
and ramus heights on
orthopantomograms.
Measurement on the
orthopantomogram
(OPG), according to
Habets et al. O1 and
O2, most lateral
points of the ramus;
A, ramus tangent; B,
perpendicular line
from A to the most
superior part of the
condylar image; C,
corpus tangent; CH,
condylar height; and
RH, ramus height.

Three-
dimensional
computed
tomography
(CT) can
provide
information
for use in
diagnosis
and
treatment
planning.
Landmarks and reference planes used in this study. A and D. Frontal view; B and E. Lateral
view; C and F. View from below. D and E. Show the ramal inclination in the frontal and
lateral directions to FH plane (ARI, anteroposterior ramal inclination; MRI, mediolateral
ramal inclination). Please see Table 1 for abbreviations of the landmarks.

Because of the
complex three
dimensional nature
of facial asymmetry,
CT scans have
become routine in
the evaluation of
asymmetry cases
that cannot be
assessed using
conventional
methods.
Reconstructed CT scan of face showing
(a) Facial asymmetry, protruding upper
central incisors. (b) Bony synostosis
between the right zygomatic arch of
maxilla and the ramus of the mandible.
(c) Normal temporomandibular joint on
right side is seen.

computerized
tomography scan (CT or CAT
scan) uses computers and
rotating X-ray machines to
create cross-sectional images
of the body. These images
provide more detailed
information than normal X-ray
images. They can show the
soft tissues, blood vessels,
and bones in various parts of
the body.

Cone-beam computed
tomography systems
(CBCT) are a variation of
traditional computed
tomography (CT) systems.
The CBCT systems used
by dental professionals
rotate around the patient,
capturing data using a
cone-shaped X-ray beam

Magnetic resonance imaging (MRI) is a medical
imaging technique used in radiology to form
pictures of the anatomy and
the physiological processes of the body. MRI
scanners use strong magnetic fields, magnetic field
gradients, and radio waves to generate images of
the organs in the body. MRI does not involve X-
rays or the use of ionizing radiation, which
distinguishes it from CT and PET scans. MRI is
a medical application of nuclear magnetic
resonance (NMR) which can also be used for
imaging in other NMR applications, such as NMR
spectroscopy

The
evaluation of
frontal facial
photographs is
a diagnostic
tool used to
evaluate soft-
tissue
asymmetry
and lip cants.

It was
concluded
that an OP
angle of
2.15–2.90
degrees on
a digital
photograph
is
acceptable.
27-year-old patient with active condylar hyperplasia on
the right side, inclination of the occlusal plane in both
maxilla and mandible
(AeC) patient exhibits the OP with a 2.5 degrees
transverse cant, having the interpupillary line as the
reference plane

The incidence of a
cant greater than 1
degree between the
bilateral mouth
corners was found to
be 28.6% when the
face was measured
on standardized
frontal facial
photographs.
- Relationship established between
occlusal plane and maxillary and
mandibular inferior borders.

Canted occlusal plane ; etiology and evaluation part 1

Canted occlusal plane ; etiology and evaluation part 1

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Canted occlusal plane ; etiology and evaluation part 1