orthodontic correction of canted occlusal plane 2

Dr Maher Fouda
Professor of orthodontics
Faculty of Dentistry
Mansoura Egypt
Orthodontic canting
of the occlusal plane
Part 2

In modern analysis, another curved line characterizing
the appearance of the dentition is important, the one that is
seen when evaluating anterior tooth display .
This line, the esthetic line of the dentition, follows the facial
edges of the maxillary anterior and posterior teeth. The orientation
of this line, like the orientation of the head and jaws,
is best described when the rotational axes of pitch, roll, and
yaw are considered in addition to transverse, anteroposterior,
and vertical planes of space.

Esthetic line of the dentition. For over a century, Angle’s
line of occlusion has been used to characterize the positions
of the teeth within the dental arch and as a reference for
assessing arch form and arch symmetry. Angle’s concept was
that if the buccal occlusal line of the mandibular dental arch
was coincident with the central fossae line of the maxillary
dental arch and the teeth were well-aligned, ideal occlusion
would result. The line of occlusion is hidden from view when
the maxillary and mandibular teeth are in contact.

There is a significant distinction between the occlusal
plane and the functional line of occlusion. The occlusal
plane is a flat two-dimensional construction, versus the
line of occlusion, which is a three-dimensional structure
created by the curve of Spee and lack of bilateral
vertical symmetry. When the upper and lower lines of
occlusion are mis-aligned, one cannot describe their
relation-ship using planes

A ,Airplanes can move in 3 planes (front/ back, side to side, and up and
down), and can also rotate around 3 axes (horizontal, axial, and vertical),
thus giving pilots 6 options for changing direction of plane’s motion.
Movement around 3 axes is called pitch, roll, and yaw. Complete description
of plane’s orientation in space requires consideration of all 6
attributes.B,3Danalysis of orientation of the head, jaws, and dentition is
incomplete without also considering 3 rotational axes of pitch, roll, and yaw
in addition to planar terms antero-posterior, transverse, and vertical.

Roll, which is analogous to the banking of an airplane, is
described as rotation up or down on one side or the other.
On clinical examination, it is important to relate the transverse
orientation of the dentition (the esthetic line) to both
the facial soft tissues and the facial skeleton.

The smile line or smile arc is defined as the
relationship between the maxillary
incisal edge and the superior border of the lower lip.
Incisal edge in relation to smile line. On the right, convex smile line (the incisal line) is
parallel to the lip curvature. The middle picture shows straight smile line. The left picture is reverse
smile line which is the least attractive smile
The presence of dental and skeletal canting should be
noted in the diagnostic stage

The functional line of occlusion illustrates arch form,
arch width, and symmetry. It does not describe the
position of the anterior teeth relative to the facial soft
tissues, that is, anterior tooth display and smile arc. In
order to describe the dental and soft-tissue
contributions to anterior tooth display, another line
must be used. This line, the estheticlineof the dentition,
follows the facial surfaces of the maxillary anterior and
posterior teeth .
A cross-sectional “block” of a CBCT image can be
manipulated on the computer screen around all three
rotational axes. This image is a different from the
submental-vertex CBCT view of an individual with
normal occlusion.

arch is rotated off to one side. If a true yaw discrepancy is
present, the next question is whether the jaw itself is deviated,
or whether the dentition deviates relative to the jaw.
Dental midline deviations can be just a reflection of displaced
incisors because of crowding. This should be differentiated
from a yaw discrepancy in which the whole dental
Midline (Front Full-Face Smiling
This is a vertical line which dissects the face vertically and can use glabella (the point where the nose and forehead connect) and
filtrum or cupid’s bow, as a facial reference. Ideally, the facial midline and the dental midline should coincide, but often they do not.
As long as the midline is perpendicular to the occlusal plane, the dental midline can be up to 2 mm off-center and the human eye
can barely detect the disparity

Roll describes the vertical position of the teeth when this is different on the right
and left sides. A, A downward roll of the dentition
on the right side, relative to the intercommissure line (yellow). Note that the
maxillary incisors tilt to the left. The chin deviates to the left, reflecting
asymmetric mandibular growth with lengthening of the mandibular body and ramus
on the right side. The vertical position of the gonial angles can be
confirmed by palpation. In this case there is a skeletal component to the roll. B,
Roll of the dentition down on the right side and slightly up on the left,
relative to the intercommissure line. There is no transverse displacement of the
chin, but the entire right side of the face is larger—note that the
interocular line rolls opposite to the esthetic line of the dentition. C, A Fox plane
demonstrates the orientation of the occlusal plane relative to the interocular
line, but the relationship of the teeth to the intercommissure line cannot be
observed while using it.

Rotation of esthetic line of dentition around horizontal axis, up or down on right or left
side ,is best described as roll. To evaluate roll relative to soft tissues, intercommissure
line is best reference; to evaluate it relative to facial skeleton, interocular line is usual
reference. A,Downward roll of dentition on right side relative to intercommissure line;B,
roll of dentition down on right side and slightly up on left, relative to intercommisure line.
There is no transverse displacement of chin ,but entire right side of face is larger—
interocular line rolls opposite to esthetic line of dentition.C,Fox plane demonstrates
orientation of occlusal plane relative to interocular line, but relationship of teeth to
intercommisure line cannot be seen while using it

A yaw deviation of the maxilla is possible but rare; an asymmetry
of the mandible that often includes yaw is present in
40% of patients with deficient or excessive mandibular
growth, and in these patients the dentition is likely to be
deviated in a compensatory direction relative to the jaw. All
of this can be detected with a careful clinical examination—
and must be because it may not be seen clearly in typical
diagnostic records.
A, Patient with upper midline deviated approximately 2 mm to the right of the
facial midline. B, Patient with upper midline deviated approximately 1 mm from
the facial midline. The inclination of the line described by the interproximal
contact area accentuates the midline discrepancy

Despite these additions to the diagnostic evaluation,
dentofacial
traits still can be adequately delineated by five major
characteristics. The additional items that now must be
included in diagnostic evaluation and classification. Examining
the five major characteristics
in sequence provides a convenient way of organizing the
diagnostic information to be sure that no important points
are overlooked.

The facial midline,
interpupillary line and
incisal line should be in
symmetrical harmony
(note minor nasal
asymmetry)
The facial and dental
midline should coincide for
optimum esthetics
This patient’s midlines do not
coincide; thus, the mandibular
midline cannot be used as a reference
point for the final restorations

Downward or upward displacement of dentition viewed along
esthetic line is best described as translation (no tilt) or pitch
upward or downward anteriorly or posteriorly. A, Downward
pitch anteriorly to point that esthetic line disappears behind
lower lip with almost no incisor display ;B, for this patient,
entire maxillary dentition is displaced downward, but, on
careful clinical examination, downward pitch posteriorly can
be seen.

Normal occlusion ,normal occlusion
plane and coincident midlines

Occlusal plane is the line along which the teeth
function and is considered to be an important
reference plane to achieve functional balance.

Symmetry is shown in this example. The maxillary
and mandibular dental midlines should be coincident.
The gingival heights between the central incisors,
lateral incisors, and canines should be balanced. From
the central incisors, moving distally from the midline,
the degree of mesial tipping should progressively
increase.

Occlusal plane positioned horizontally

symmetrical face with interpupillary line (IP) and commissural line
(CL) parallel. Facial midline coincident with maxillary dental midline,
medium lip line, and convex smile line determined. The anterior and
posterior
occlusal planes were paralell.
Perception of occlusal plane that is nonparallel
to
interpupillary and commissural lines but with the
maxillary
dental midline ideally positioned
Marta Revilla-León, DDS, MSD, Matthew J. Meyer, Jennifer J. Barrington, DDS, Amerian Sones, DDS, MSD,
Mikhail P. Umorin, PhD, Mohsen Taleghani, DDS, and Amirali Zandinejad, DDS, MS
THE JOURNAL OF PROSTHETIC DENTISTRY
2019
interpupillary line
commissural line

The Incisal Horizontal Plane
The interpupillary line is a reference plane used to
determine the incisal horizontal plane, gingival plane
and occlusal plane. An incisal plane cant of 1 mm is
rated as significantly less aesthetic. Kockich found that
an occlusal plane cant is a very displeasing smile
characteristic to health professionals and laypeople. An
incisal occlusal cant is a form of asymmetry that is
apparent when a person smiles but is not perceived on
intraoral images or study casts
The two lines show the disparity between the incisal
horizontal plane and the position of the cusp tips of the
canines.

Canting of maxillary incisal plane

An anterior-posterior
cephalometric radiograph
documents facial asymmetry,
occlusal canting and mandibular
deviation.
Maxillary dental midline deviated 3mm to the right,
occlusal plane cant 5mm superior on the patient’s
right side, 5mm chin deviation to the right

Bimaxillary Protrusion with Missing Lower First
Molar and Upper Premolar:
Asymmetric Extractions, Anchorage Control
and Interproximal Reduction
IJOI 44 iAOI CASE REPORT
A 38-year-old woman sought orthodontic evaluation
with concerns about missing teeth, an unesthetic
anterior dentition, prominent lower incisors and
protrusive lips
Extra-oral evaluation with the lips closed showed
symmetric bimaxillary protrusion with coinciden
dental and facial midlines. Upon smiling her dentiti
was unattractive due to an end-to-end incisal
relationship, occlusal cant (more inferior on the rig
side), irregular spacing in the anterior segments, a
intermaxillary midline diastemas

A 13-year-old female patient presented with a chief
complaint of malaligned teeth associated with an
anterior asymmetric deep bite.
Extra-oral photos
revealed a symmetrical face and a low smile line
(exposing less than 75% of the anterior maxillary
teeth)
Class II and Class
III dental relationship was evident on the right and
left side, respectively. The occlusal plane was canted
upward on the right side. Both dental midlines were
displaced to the right with the mandibular midline
displaced 3 mm more than the maxillary midline.
Asymmetric deep bite with a canted occlusal
plane: a case report
Teresa Pinho
Australian Orthodontic Journal Volume 29 No. 1 May 2013

A 10K year old Caucasian female patient with HM
Treatment of hemifacial microsomia in
a growing child: the importance of
co-operation between the orthodontist
and the maxillofacial surgeon
C. Moulin-Romse´e, A.Verdonck, J. Schoenaers and C. Carels
Katholieke Universiteit Leuven, Belgium
JO September 2004
And asymmetric lower half of her
face. She showed a remarkable facial hypoplasia on the
right side with the chin deviating to the right also,
resulting in a severe asymmetric occlusion
There was a severe
asymmetry in the lower posterior face height. The
occlusal plane in the upper jaw was inclined upwards to
the right and there was marked dentoalveolar
compensation.

Class II malocclusion with accentuated occlusal
plane
inclination corrected with miniplate: a case report Dental Press J Orthod. 2016 May-June;21(3):94-103
Angle Class II,
Division 1 malocclusion
This was caused
by absence of maxillary left lateral incisor and mandibular
left second premolar, with ankylosis of deciduous molar
in this region.
Facial analysis revealed good symmetry and
vertical balance of the facial thirds, a convex profile, and
accentuated occlusion plane inclination in a smiling
photograph
A 29-year-old woman sought orthodontic treatment,
complaining about an unesthetic smile due to occlusal
plane inclination and midline deviation.
Maxillary
midline was deviated 2 mm to the left while mandibular
midline was deviated 2 mm to the right.
Marcel Marchiori Farret, Milton M. Benitez Farret

Angle Orthodontist, Vol 84, No 4, 2014Management of occlusal canting with miniscrews
Rosa Maria Ya´n˜ ez-Vicoa*; Alejandro Iglesias-Linaresa*; Maria Cadenas de Llano-Pe´ rulab;
Alvaro Solano-Reinaa; Enrique Solano-Reinac
the patient presented a gummy smile,
which was accentuated on the left side due to the canted
occlusal plane
He had
a 7-mm overjet, with bilateral Angle Class I molars and
Class II canines.
A 14-year-old boy

A 26-year-old woman presented with excessive
gummy upper smile and an unattractive profile..
Facial examination revealed facial asymmetry
accompanied with occlusal plane canting.
Clinical intraoral examination found teeth #26 and #46 to be
missing and the presence of a deep bite and occlusal plane
canting. Panoramic radiography revealed teeth #26 and #46 to
be missing and #16 to be super-erupted
Improved Super-elastic Ti-Ni Alloy Wire for the Treatment of Adult
Occlusal Plane Canting with a Gummy Deep Bite Case: A Case Report
Chen Tzu-An, Lo Yu-Cheng, Hsu Meng-Chu, Yu Jian-Hong, Chen Yuan-Hou
Am J Den and Ora Car. 2020; 3(2): 01-05

Bracket Placement According to Malocclusion
By Johnny Holanda de Gauw, DDS; Giordani Santos
Silveira, DDS; José Nelson Mucha, DDS, MSc, PhD
IJO  VOL. 26  NO. 3  FALL 2015
A 25-year-old female patient. She had a mild frontal asymmetric face, but her only complaint
was the asymmetric superior occlusal plane, notably on smiling, and consequently the lower
arch followed these upper disharmonies, but to a lesser extent. She presented with a Class I
relationship and mild lower teeth crowding.
Canted occlusal plane

The transverse cant of the maxillary occlusal plane can be due to
differential dental eruption . Display of the anterior teeth can be
modified orthodontically, surgically, or with cosmetic periodontics.
Skeletal asymmetry of the mandible will resultin a compensatory
cant to the maxilla, often requiring orthognathic correction.
Maxillary vertical asymmetry.(a)Unilateral
non reducing TMJ meniscus and
advanced osteoarthrosis caused
mandibular asymmetry on the short side.
(b)Occlusal plane tipped as a
compensation to mandibular asymmetry.
(c)Occlusal plane and smile made level
with symmetric facial components after
maxillary surgical, orthodontic, and
periodontal therapies. Frontal imaging at
(d)pre-treatment and (e)post treatment,
and(f)frontal summary analysis. The
patient had a Class II malocclusion

he oblique view of the smile reveals characteristics of the smile not
obtain-able on the frontal view and certainly not obtainablethrough
any cephalometric analysis. The palatal plane may be canted
anteriorly or posteriorly. In the most desirable orientation, the
occlusal plane is con-sonant with the curvature of the lower lip on
smile. Modification of the occlusal plane in preadolescents can be
accomplished with growth modification appli-ances such as vertical
control functional appliances, the differential Herbst appliance, and
high-pull head-gear
(g)Asymmetric smile
plane. (h)Short-side
Class II problems.
(i)Optimized occlusal
correction. (j)Differential
posterior tooth eruptions
to level the occlusal
plane.

A, Facial asymmetry developed in this boy after fracture of the left mandibular condylar
process at age 5 because scarring in the
fracture area prevented normal translation of the mandible on that side during growth . B, Note
the cant to the occlusal plane and the
resulting roll deformity . This develops as failure of the mandible to grow vertically on the
affected side restricts
eruption of both maxillary and mandibular teeth. Trauma is the most frequent cause of
asymmetry of this type.

Rotation of the jaw or dentition to one side or the
other, around a vertical axis, produces a skeletal or
dental midline discrepancy that is best described as yaw
. Yaw of the dentition relative to the jaw, or yaw
of the mandible or maxilla that takes the dentition with it,
may be present. The effect of yaw, in addition to dental and/
or skeletal midline deviations, typically is a unilateral Class
II or Class III molar relationship. Extreme yaw is associated
with asymmetric posterior crossbites, buccal on one side and
lingual on the other. Yaw has been left out of all previous
classifications, but characterizing transverse asymmetries
in this way makes it easier to accurately describe the
relationships.

A, Yaw of the maxillary dentition to the left side is apparent in this girl, who also
has slight yaw of the mandible in the same direction.
Note that the yaw of the esthetic line of the dentition is greater than the yaw of
the chin. In her clinical examination, it will be important to evaluate
the relationship of the midline of the mandibular dentition to the chin. A
compensatory yaw of the mandibular teeth back toward the skeletal midline
often is present in patients with this type of asymmetry. B, Severe yaw of the
maxillary dentition to the right in this woman, who has almost no yaw
of the mandible. Note that she also has more elevation of the right commissure
on smile, so relative to the intercommissure line, she has a downward
roll of the dentition on the right. This should be noted in the clinical examination
because it will be important to determine whether she considers it a
problem.

In late adolescent and adult patients, surgical
modification of the maxillary occlusal plane is often
indicated. Clockwise occlusal plane rotation by maxillary
or double-jaw surgery may harmonize the positions of
the maxillary incisal edges with the lips.
(a)Significant hemimandibular hyperplastic asymmetry.
(b)Facial assessment is facilitated with acetate overlay upon
patient photo

A common method of assessing canting of the maxillary
occlusal plane is by placing a wooden tongue spatula across
the premolars and relating it to the inter-pupillary line

Clinical assessment of the
canted occlusal plane .

Facial evaluation is an integral part of patient examination. It starts with evaluating
facial symmetry, as symmetric faces are considered more beautiful than those
that are not . The facial midline is the reference used to assess facial symmetry
. Facial examinations begin with symmetry evaluation and then establish
the interpupillary line and determine whether it’s normal (perpendicular to the
facial midline) or slanted. Both jaws should be assessed in reference to the facial
midline to determine any canting. The position of the chin should also be marked
for any deviation.
Facial midline,
interpupillary line

The relationship
to the facial soft tissues is evaluated clinically with the intercommissure
line as a reference. Neither dental casts nor a
photograph using an occlusal plane marker (Fox plane) will
reveal this. It is seen with the lips relaxed and more clearly
on smile, in both frontal and oblique views .

The relationship to the facial skeleton is
viewed relative to the interocular line. The use of a Fox plane
to mark a cant of the occlusal plane may make it easier to
visualize how the dentition relates to the interocular line, but
with this device in place it is impossible to see how the teeth
relate to the intercommissure line.
Canted maxillary anterior occlusal plane.

Chair side measuring instrument for
quantification of the extent of a transverse
maxillary occlusal plane cant
Maxillofacial Plastic and Reconstructive Surgery (2019) 41:21
A measuring instrument may be constructed by soldering
the edge of a double-sided stainless steel dental ruler at
90° to the flat surface of a similar ruler.
The measuring instrument is
constructed by soldering the edge
of a
double-sided stainless steel
dental ruler at 90° to the flat
surface of a similar
ruler. A double-sided ruler permits
its use on the patient’s right and
left sides
as required. A right-angle gauge
may be used to ensure a 90°
angle

With the
patient in natural head position, near a vertical plumb line
(forming a true vertical line), and a dental photographic
retractor in situ
Patient is shown in natural head
position. The oral retractors are in
situ, and a plumb line is evident hanging
to the patient’s right side, which
acts as a guide to the true vertical line. A
transverse cant of the maxillary
occlusal plane, down on the patient’s
right side, is evident. The patient may
be positioned in a cephalostat as
demonstrated here, though this is not
mandatory, and for most patients sitting
in the dental chair will suffice

the flat under-surface of the horizontal
part of this measuring instrument is placed on the
higher maxillary canine orthodontic bracket hook and
held perpendicular to the true vertical .

The flat under-surface of the horizontal part of the measuring
instrument is placed on the higher maxillary canine orthodontic bracket
hook (though it may be placed on a unilateral segment of any bilateral
structure), and held perpendicular to the true vertical. For patients with a
relatively symmetrical upper face, and no vertical orbital dystopia, the
horizontal part of the measuring instrument may be held approximately
parallel to the interpupillary plane (a dental mirror handle may be held in
line with the interpupillary plane, to aid visualisation at the chair side). The
vertical ruler is held next to the contralateral canine tooth, and the vertical
distance measured directly from the canine bracket to the flat undersurface
of the horizontal part of the measuring instrument. This vertical
distance quantifies the overall extent of movement required to level the
maxillary occlusal plane

The vertical
ruler is held next to the contralateral canine tooth, and
the vertical distance measured directly from the canine
bracket to the flat under-surface of the horizontal part of
the measuring instrument. Alternatively, if the patient is
seated upright in the dental chair, the horizontal part of
the instrument may be held parallel to the interpupillary
line, assuming no vertical orbital dystopia is evident.

It is worth emphasizing that the instrument may be
held relative to a true vertical plumb line hanging from
the ceiling if a patient has a severe craniofacial asymmetry
and vertical orbital dystopia.

Occlusal plane, when viewed from the frontal
aspect, is an expression of vertical position of
teeth on right and left sides of dental arch.
Therefore, when vertical relationship of teeth
along this plane on one side of the arch is
assessed with respect to the other, it forms an
integral part of transverse assessment to
determine the cant of occlusal plane.

Occlusal plane changes in transverse dimension are
true reflection of relative vertical heights of the
segments of teeth on the left and right sides, as a
result of differential vertical dentoalveolar growth,
vertical eruption of teeth on one side of the arch or
underlying skeletal discrepancy .
Canted maxillary anterior occlusal plane.

Canted occlusal plane may involve both upper and
lower arches; however, in majority of the patients, the
problem is limited to either the upper or lower arch or
isolated to anterior or posterior segment.

Occlusal plane canting is one characteristic that must be evaluated
in any assessment of smile esthetics. It describes the vertical position
of the teeth when the left and right sides are different and this is
defined as the rotation upwards or downwards in the transversal
plane of one side over the other.
Photo of smile modified to create
occlusal canting of 4º
Photo of smile with 0º occlusal
canting
Photo of smile modified to create
occlusal canting of 2º
Occlusal plane canting of 0º and 2º were evaluated as esthetically acceptable
Canting of the occlusal plane: Perceptions of dental
professionals and laypersons
Med Oral Patol Oral Cir Bucal. 2013 May 1;18 (3):e516-20

Occlusal plane can be observed both in the frontal
plane and obliquely, whenever the lips are relaxed
but most clearly in the smile

The importance of evaluating the transverse cant of the occlusal
plane in intraoral photographs
C.B. Pereira et al. / Journal of the World
Federation of Orthodontists 3 (2014) e19ee25
Some studies recommend that intraoral photographs be
exhibited with the occlusal plane (OP) parallel to the
horizontal
frame of the image, and centered.
Intraoral photographs taken according to the recommendation of placing the OP in a
horizontal position and centered on the image.

This
recommendation, that is, to show the OP horizontally,
constitutes
an attempt to avoid presenting photos with different
inclinations
and looking unrealistic.
Clinical case mounted with unreal inclinations, as proven clinically. This set of images not only shows unreal
inclinations but also discloses a disproportion between the 3
image sizes.

recommended in the literature,
compromised a proper
diagnosis because the
patient’s OP showed
significant inclinations.
A clinical case in which the
photographs were artificially
mounted horizontally, as
Photographs mounted with OP positioned horizontally.
Sometimes a true OP inclination can be altogether different from one artificially oriented horizontally, as in this case.

a frontal view intraoral photograph of a patient
with the OP in a horizontal position and centered on
the image, as recommended in the literature.

However, a physical examination of this patient,
using the interpupillary line as reference, revealed a 2.5
degrees transverse
inclination in the OP.

After evaluating computed tomography scans, the OP
should be perpendicular to the true vertical
plane.

The presence of a cant in the transverse occlusal plane may be observed
in relation to the interpupillary line ( or a true horizontal plane ) with the
patient biting on a wooden spatula ( or holding it against the maxillary
teeth if there is a lateral open bite ) , both in the incisor/ canine and the
premolar / molar region , or a Fox occlusal guide plane.
Fox occlusal guide planePatients with asymmetrical smiles due to structural maxillary
occlusal cant .

In the absence of a transverse
maxillary cant and / or vertical
orbital dystopia , the transverse
occlusal plane should be parallel
to the interpupillary line .
Vertical orbital dystopia occurs in
facial clefts when the orbital floor
and/or the maxilla is involved. This
means that the eyes are not on the
same horizontal line on the face (one
eye is positioned lower than the other)

C.B. Pereira et al. / Journal of the World Federation of
Orthodontists 3 (2014) e19ee25
Kokich et al. found that dentists could perceive an OP
transverse cant with a 1-mm discrepancy, whereas laypersons
could perceive only discrepancies of 3 mm or larger. Those investigators
concluded that general practitioners and orthodontists,
in that order, are supposed to draw a patient’s attention to any
noticeable discrepancies, and then allow the patient to determine
for his- or herself the overall esthetic significance of each
discrepancy.
Use of the fox occlusal plane guide to evaluate the orientation of the transverse maxillary
occlusal plane.

Care should be taken to avoid being misled
by over-erupted teeth or canine cusps of
different lengths, which may tip the spatula
in a way that does not accurately reflect the
skeletal base
Relationship established between occlusal plane and
maxillary and mandibular inferior borders

clinically patients who had not previously perceived the presence of a
transverse occlusal cant often become acutely aware of it once it has
been pointed out, by either someone who has a keener sense of
observation or by a dentist. Thus, it is imperative that the true cant
of the OP be evaluated, studied, documented and treated, if so
indicated.
Use of the wooden spatula to evaluate the orientation of the
transverse maxillary occlusal plane.

Historically, dentistry has adopted the anthropologic concept
that cranial observations, descriptions, and measurements should
use the Frankfort plane as a horizontal reference line.
However, in the case of frontal view facial photographs, the interpupillary
line may be used instead of the Frankfort plane as the true
horizontal reference.
drawn from the ear canal to the bony ridge under the eye (infraorbital rim
the Frankfurt Horizontal Plane is

Interpupillary line is an
imaginary horizontal line
drawn between the centers of
the pupils of the eyes
The interpupillary line replaces the
Frankfort plane, which cannot be drawn
accurately on facial
photographs.

Facial asymmetry is a common condition that can lead to
asymmetry of the interpupillary line. However, due to the cephalocaudal
gradient of growth, the further away the structures are
from the cranial base, the more pronounced the asymmetries .
Thus, even if the eyes are asymmetrical, jaw asymmetries are
usually more pronounced, making the interpupillary line a relatively
reliable reference line. Growth discrepancies lead much more
frequently to a transverse cant of the OP than to a cant or inclination
of the interpupillary line.
Cant of the occlusal plane in
transverse plane is often seen in cases
of facial asymmetry
This man has unilateral
condylar hyperplasia of
the left side leading to a
transverse cant of
occlusal plane .
Frontal photograph showing chin deviation and tilted lip
commissure plane

Delineation of occlusal plane
on the photographic record

The diagnostic part of smile analysis begins with the creation of a
problem list. The first set of records analyzed is the extraoral photo
gallery ,consisting of the captured social smile, the full
facial portrait at rest, the three-quarter smiling view,
and the profile view.
The Close up Smile View A scale of 1:2 should be used, if
the camera has a full frame sensor. •The patient should
be at full smile, in order to assess the lip line. •The
occlusal plane should be horizontal. •Keep the lens axis
in line with the occlusal plane, so that the camera is not
looking up or down at the patient’s mouth. •Focus on the
second incisors

A cant to the occlusal plane can be seen in both frontal (A) and oblique (B)
views. This is a “roll deformity” that results from the
orientation of the jaws and teeth rather than their position (discussed further
in the classification section of this chapter). It becomes an esthetic problem
if it is noticeable, and lay observers do notice a cant of this degree of severity.

The true OP cant may be documented on intraoral photography
using 3 different techniques: 1) horizontal positioning of the patient
and the camera; 2) inclusion of the eyes in the picture, using
the interpupillary line as horizontal reference, and with the patient
biting on a wooden tongue depressor; and 3) inclusion of the eyes
and dental arches, with the patient using lip retractors.
12-year-old male patient with maxillary constriction and unilateral crossbite due to mandibular shift to right.
Mandibular incisal cant is camouflaged by crossbite.
Correction of a Canted
Lower Incisal Plane
JCO/SEPTEMBER 2006

Intraoral photographs positioning patient and camera
horizontally
To photograph the true OP inclination, both the patient and the
camera should be positioned horizontally. The top of the viewfinder
and the interpupillary line should both be horizontal .
OP perpendicular to the true vertical (VV) plane.
a viewfinder is what the photographer looks through to
compose, and, in many cases, to focus the picture.

The camera should be positioned in
such a manner as to
encompass all teeth and gingival
tissues, as shown in. The
depth of field should be as deep as
possible so that both the incisors
This can be achieved by focusing on an
intermediate area, which, in the frontal
view intraoral photo, corresponds
to the canine/first premolar area.
and the molars are in focus.
To photograph the true OP inclination,
both the interpupillary line and the
camera must be horizontally
positioned. It should be emphasized
that the frame of the photograph
solely includes the intraoral
structures, as shown by the dark
frame and also by the camera’s
viewfinder. The interpupillary line is
shown here only to facilitate the
understanding
that the patient should be positioned
with this line parallel to the horizontal
plane, but it does not appear in the
photograph.

Intraoral photograph taken with eyes included in the picture,
using the interpupillary line as horizontal reference, and biting on a
wooden tongue depressor
Because it is difficult to trace a line that accurately represents the
OP on photographs;
photograph patients while they are biting
on a wooden tongue depressor. The angulation of the depressor
helps to accurately determine whether there is an OP cant relative
to the interpupillary line.
Patients biting on a wooden tongue depressor,
which accurately reveals their transverse OP cant.

The transverse OP
cant may be evaluated
qualitatively by comparing the
interpupillary
line with the cant of the tongue
depressor.
To quantitatively
determine the discrepancy, a line running
parallel to the OP line is
projected next to the interpupillary line,
and the angle formed
between these 2 lines is measured (in this
case, a 4.5 degrees angle .
A line is traced parallel to the OP line, transported to the interpupillary line,
and the angle formed by the these 2 lines is measured. In this case, there is a 4.5 degrees
discrepancy in the angle.

This information needs to be transferred to the patient’s
intraoral image, which is accomplished as follows. Assuming that
the interpupillary line runs horizontally and that the photo frame is
also horizontal, a line is traced at a 4.5 degrees cant relative to the superior
frame of the intraoral photograph .

This line exhibits the
true OP cant (the computer program traces this frame with horizontal
and vertical lines). By projecting the line that represents the
OP onto the OP region, it becomes clear that the image would need
to be rotated .

Using the program’s graphical resources, the
image can be rotated 4.5 degrees . The procedure is
finalized by
digitally cropping the image .

Intraoral photograph encompassing the eyes and dental arches,
with patients using lip retractors
Another method to determine the true
transverse OP inclination
is to take intraoral photographs with
lip retractors and encompassing
the patient’s eyes,
which are used as a
horizontal reference.
The use of lip retractors
improves visualization of
the dental arches .
Both dental arches and eyes are included in this photograph displaying the OP
cant.

To obtain this photograph, it is recommended
that the center of the image coincide approximately with
the midpoint of the incisors (similar to using the tip of the nose, in
the case of facial photographs).
The image should be centered approximately on the intersection of the incisors.

To facilitate observation of the OP cant, it is suggested that an
interpupillary line be traced and a parallel line be transported to the
OP region. To ensure an even better assessment of the OP cant, a
vertical line can also be traced. It is advisable
to digitally crop the image, displaying only the intraoral view.
An interpupillary line should be drawn to serve as reference for the actual OP
inclination. To measure the OP cant, a line can be drawn running parallel to the
interpupillary line, and then be transported to the OP region.
Digital cropping to obtain an intraoral
photograph.

Take lateral cephalometric
radiograph

Next, the cant of the maxillary
occlusal plane relative to Frankfort horizontal
should be assessed visually on the lateral
cephalogram and measured on the tracing.
Before cephalometric evaluation, a piece of lead
foil was placed (dentulous patients using
composite) on the mesioincisal edge of central
incisor and mesiopalatal cusp of molar
Following lead foil placement, the lateral
cephalogram was taken
with Frankfurt horizontal plane parallel to the
ground in a cephalostat
Tracing was done to
evaluate the angle between Frankfurt horizontal
plane and the occlusal plane (formed by line
joining th
e mesiopalatal cusp of upper molar and
incisal edge of central incisor)
Lead foil fixed on mesiopalatal cusp of
maxillary left molar and mesioincisal edge of
maxillary left central incisor using composite
Tracing of lateral cephalogram of
dentulous patient

INCISAL PLANE DISCREPANCIES
Esthetics and Anterior Tooth Position:
An Orthodontic Perspective
Part 11: Vertical Position
VINCENT KOKICH. DDS"
JULYIAUCUST 1993
Discrepancies in the maxillary
anterior
incisal plane have various causes.
The treatment of these problems
may require surgical movement of
the maxilla, orthodontic intrusion
or extrusion of the incisors, or
orthodontics in combination with
restorative care.

JULYIAUCUST 1993
The correct solution
depends on the interrelationship
of the following four factors:
1. Posterior occlusal plane,
2. Incisal plane,
3. Interpupillary line, or
4. Crown length of the
maxillary
incisors .
Symmetry in the maxillary
incisal plane is based on the interrelationship
Of the posterior occlusal plane, the
incisal plane, the interpupillary line, and
the crown lengths of the maxillary central
and lateral incisors.

JULYIAUCUST 1993
If the maxillary incisal plane
deviates
from the interpupillary line,
but coincides with the maxillary
occlusal (posterior) plane, the
entire
maxilla developed
asymmetrically
due to uneven
growth of the mandibular rami.
A and B, The
maxillary incisal plane deviates from
the interpupillary line. C, The incisal
plane coincides with the posterior
occlusal plane indicatin uneven
growth of the mandibufzr rami. D,
Postoperative correction of maxilla

JULYIAUCUST 1993
This causes the maxillary teeth on
one side of the arch to erupt more
than the other. This problem
cannot
be treated orthodontically. It
requires
maxillary surgery to intrude the
maxilla on the overerupted side,
level the occlusal and incisal
planes,
and correct the vertical
discrepancy.

JULYIAUCUST 1993
If the maxillary incisal plane deviates
from the interpupillary line and
does not coincide with the maxillary
occlusal (posterior) plane, the
problem does not require surgery. If
the lengths of the right and left
centrals
are bilaterally symmetrical,
then the problem can be corrected
orthodontically by extruding or
intruding teeth .
If the incisal
plane and the occlusal plane are
not coincident, but the crown
lengths of the central and lateral
incisors are bilaterally symmetrical,
orthodontics are indicated
to level the incisal plane. Note
that the maxillary incisal plane
deviates from the interpupillary
line preoperatively.

Part 11: Vertical Position VINCENT KOKICH. DDS"
JULYIAUCUST 1993
The incisal plane does not coincide with the
occlusal plane or the interpupillary line. The
incisal edges on the right side have been
worn due to an anterior crossbite. Leveling
the gingival margins orthodontically is
followed by restoration of the incisal edges
If the posterior occlusal plane
coincides
with the interpupillary line,
but the incisal plane deviates from
both of these landmarks, and the
lengths of the central and lateral
incisors are uneven, there has been
oblique wear of the anterior teeth
requiring restorative care following
completion of the orthodontics

A third important relationship to note is whether an
up-down transverse rotation of the dentition is revealed
when the patient smiles or the lips are separated at rest
. This often is called a transverse cant of the
occlusal plane but is better described as a transverse roll of
the esthetic line of the dentition .
A and B, The
maxillary incisal plane deviates from
the interpupillary line. C, The incisal
plane coincides with the posterior
occlusal plane indicatin uneven
growth of the mandibufzr rami. D,
Postoperative correction of maxilla.

Neither dental
casts nor a photograph with lip retractors will reveal this.
Dentists detect a transverse roll at 1 mm from side to side,
whereas laypersons are more forgiving and see it at 2 to
3 mm—but at that point, it is a problem.

Following clinical assessment, the asymmetry if present
must be quantified to allow an objective decision
regarding the need for treatment. Although it
is difficult to diagnose a 3D deformity from a 2D
panoramic radiograph, the linear and angular
measurements from a panoramic x-ray can provide
important evidence of an asymmetry .
A. Linear measurements from height of condyle and most
distal point of condyle to most posterior point on ramus of mandible
depict discrepancies between right and left rami (CH = condylar
height; RH = ramal height; Asymmetry Index = RightCH + RH
– LeftCH + RH / RightCH + RH + LeftCH + RH).

A 3D assessment of the mandibular body
curve is recommended over linear measurements
in comparing the right and left sides of the mandible.
B. Submental-vertex view
provides another way to identify asymmetry by measuring mandibular
body curve.

Relevant measurements can also be taken
from lateral and postero-anterior (PA)
cephalograms.

CBCT and other 3D imaging techniques
have made it easier to observe and quantify
condylar deformities from all possible aspects .
A. Angular and linear measurements depict discrepancies
between right and left sides of maxilla (white), chin
(yellow), ramus (green), and mandibular body (red) in lateral
and frontal views.7 B. Grid can be useful in diagnosing mild
asymmetries.

An archwire for non-invasive improvement of
occlusal cant and soft tissue chin deviation
Eric Jein-Wein Liou, Kunal Mehta James
Cheng-Yi Lin
APOS Trends in Orthodontics • Volume 9 • Issue 1 •
January-March 2019

This archwire is pre-fabricated with titanium-molybdenum alloy
(TMA) for a good range of springback.[19-21] It is a continuous
archwire with a wavy configuration resembling a symbol of yin
and yang at the front view, or a combination of curve of Spee
and reverse curve of Spee at the side view .
The configuration and orientation of an Yin-Yang archwire. An orientation of left side up Yin-Yang
archwire at the frontal view is for the correction of a left side down occlusal cant. An orientation of
right side up Yin-Yang archwire at the frontal view is for the correction of a right side down
occlusal cant.

The configuration and orientation of an Yin-Yang archwire. An orientation of left side up Yin-Yang archwire
at the frontal view is for the correction of a left side down occlusal cant. An orientation of right side up Yin-
Yang archwire at the frontal view is for the correction of a right side down occlusal cant.
The Yin-Yang archwire has 0.017 × 0.025 and 0.018 × 0.025 wire size
series. The 0.017 × 0.025 wire size is for the 18-slot size brackets, and
0.018 × 0.025 is for the 22-slot size brackets. It should be placed from
molar to molar in each tooth bracket just like a conventional plain
archwire.

The configuration and orientation of an Yin-Yang archwire. An orientation of left side up Yin-Yang archwire
at the frontal view is for the correction of a left side down occlusal cant. An orientation of right side up Yin-
Yang archwire at the frontal view is for the correction of a right side down occlusal cant.
It has 60 ‫؛‬and 100° up-and-down configurations. The 100° is for the
correction of a cant in the beginning, and the 60° is to maintain the
correction .

Mechanics of archwire
The mechanics of a Yin-Yang archwire is reciprocal extrusion and
intrusion between right and left. The wavy down wire configuration is to
extrude teeth, and the wavy up wire configuration is to intrude teeth.
The magnitude of extrusion and intrusion is equal and reciprocal. The
extrusion is an anchorage for the intrusion, and the intrusion is an
anchorage for the extrusion.

To complete the reciprocal mechanics between extrusion and
intrusion at the posterior, a transpalatal arch (TPA) or lingual
holding arch (LHA) together with a Yin-Yang archwire are
necessary for the correction of a posterior and anterior occlusal
cant. TPA and LHA may be not necessary for a correction of
anterior occlusal cant only.

Selection of archwire
It has two orientations. To select a proper orientation for the occlusal cant
correction, orient the archwire so that both ends of the archwire are at the
same level and then check the up-and-down orientation at the anterior. A
right side up occlusal cant should be corrected by an Yin-Yang archwire
with a right side down and left side up orientation at the anterior. A left
side up occlusal cant should be corrected by an Yin-Yang archwire with a
left side down and right side up orientation at the anterior .

CASE REPORT
A 21-year-old female patient seeking for no jaw bone surgery reported to the orthodontic department
with a chief complaint of “sticking out and crooked front teeth and a skewed face.” Clinical evaluation
disclosed the presence of a 2.5 mm chin deviation to the left at soft tissue Pog in reference to the
facial midline, a 5.8° left side up lip-line cant, 7.5° left side up uneven maxillary gingival
line and occlusal cant in reference to the interpupillary line, and a left
side up roll rotation excessive gummy smile.

Intraoral findings included an Angle Class I molar relationship, 3.0 mm OB, 3.0 mm
OJ, lower dental midline deviating to the right 1.5 mm in reference to the facial
midline, upper, and lower moderate anterior crowding, and proclined upper and
lower anterior teeth .

Three-dimensional cone-beam
computed tomography analysis
Three-dimensional cone-beam computed tomography (3D CBCT) analysis revealed a
Class I skeletal jaw bone relationship with bimaxillary dentoalveolar protrusion, a 3.0
mm mandibular deviation to the left at Pog in reference to the mid-sagittal plane
perpendicular to the floor, and a 7.5° left side up maxillary anterior occlusal cant
(canine to canine) and 2.5° left side up posterior occlusal cant (1st molar to 1st molar) in
reference to the FH plane .
The pre-treatment 3D CBCT of the case revealed bimaxillary protrusion with
mandibular asymmetry and a left side up maxillary occlusal cant.

Treatment goals and treatment plan
Since the patient asked for non-surgical treatment, the treatment goals
were non-surgical approaches to improve the anterior crowding,
bimaxillary dentoalveolar protrusion, gummy smile, uneven maxillary
gingival line, and occlusal cant, but ignore the soft tissue lip-line cant
and chin deviation.

Orthodontic treatment plan with extraction of the maxillary 2nd premolars
(had resin restorations) and mandibular 1st premolars for the relief of
anterior crowding and improvement of bimaxillary dentoalveolar
protrusion, intrusion of maxillary anterior teeth using intruding cantilever
arms for the gummy smile, and the Yin-Yang archwires for the maxillary
and mandibular occlusal cant was the treatment of choice after the patient
had been well-informed consent.

Sequence of orthodontic treatment
The sequence of orthodontic treatment was first extraction of the upper and lower premolars, and
alignment and leveling for relieving upper and lower anterior crowding. The maxillary and mandibular
anterior teeth were then retracted and intruded for space closure and improving the bimaxillary
protrusion and excerssive gummy smile. After the space closure, the occlusal cant was corrected by
using the Yin-Yang archwires. The final step was the lower dental midline correction and detailings.

Treatment appliances and mechanics
The upper and lower dentitions were bonded with 0.022 slot ceramic self-
ligating brackets and aligned and leveled with 0.014 and 0.016 × 0.022 NiTi
archwires first for 2.5 months after the extraction.
The maxillary and mandibular en masse retraction-and-intrusion was
completed rapidly in 6.5 months by the submucosal injection of platelet-rich
plasma in the upper and lower anterior teeth, upper and lower 0.016 × 0.022 SS
as the main archwires, NiTi coil springs for the anterior retraction, and 0.017 ×
0.025 TMA intrusive lever arms for the anterior intrusion .

After the extraction space closure and en masse maxillary and
mandibular en masse retraction-and-intrusion, the left side up lip
cant and occlusal cant were improved slightly, but the chin
deviation remained unchanged . An upper Yin-Yang archwire
followed by a lower Yin-Yang archwire was placed for 6 months to
further improve the maxillary and mandibular occlusal cant .
The changes of LC, OC, and CD before treatment (T0),
after space closure (T1), after treatment (T2), and 1 year
follow-up (T3).

An orientation of left side down and right side up maxillary Yin-Yang
archwire was applied for correcting the left side up and right side down lip
cant and maxillary occlusal cant after the extraction space had been closed
of the case.

Finally, Class II elastics were used on the right side for
the midline correction and the treatment was completed 1
year after placement of the upper Yin-Yang wire. Patient
was given lingual bonded and Essix retainers for
maintenance .

Intraorally, the Angle Class I molar relationship was maintained, the 3.0 mm
OB and 3.0 mm OJ were improved, lower dental midline deviating to the
right 1.5 mm was corrected in reference to the facial midline, upper and
lower moderate anterior crowding
was relieved, and the proclaimed upper and lower
anterior teeth were improved and uprighted .

Pre-treatment and Post-treatment 3D CBCT assessments and superimpositions
3D CBCT analysis revealed a Class I skeletal jaw bone relationship was maintained,
bimaxillary dentoalveolar protrusion was improved, a 3.0 mm mandibular deviation to
the left at Pog remained uncorrected before and after the treatment in reference to the
mid-sagittal plane perpendicular to the floor, the 7.5° left side up maxillary anterior
occlusal cant was improved to 0.5°, and the 2.5° left side up posterior occlusal cant
was improved to 1.3° in reference to the FH plane [Figure 7] [Table 1].
The changes of LC, OC, and CD before treatment (T0), after space
closure (T1), after treatment (T2), and 1 year follow-up (T3).

The post-treatment three-dimensional (3D) cone-beam computered tomograph, and the pre- and post-treatment 3D
image superimposition of the case revealed the maxillary occlusal cant was corrected through the intrusion of the
right side maxillary anterior teeth and extrusion of the left side maxillary anterior teeth. The silver color is pre-
treatment, and the red color is post-treatment.

A 22-year-old Korean man’s chief complaints were
facial asymmetry and mandibular prognathism . He had
traditional facial asymmetry, with a
skeletal Class III pattern, including anterior crossbite,
midface deficiency, and significant mandibular prognathism.
This patient had mild midfacial deficiency and
proclined maxillary anterior teeth.

His mandible was shifted to the right according
to the cant of the maxillary occlusal plane due to the
unilateral extrusion of the maxillary left premolars and
molars. The mandibular occlusal plane also was
canted slightly by unilateral extrusion of the left
mandibular molars

This extrusion accentuated
his asymmetry. The mandibular right incisors
and first premolar showed some extrusion attendant
to an anterior crossbite. The patient also had a
posterior crossbite caused by an absolute transverse
discrepancy. The maxillary midline was 1 mm to the
right of the midsagittal plane, and the mandibular
midline was off by 3 mm in the same direction.

The
anterior teeth of both arches had typical Class III
dental compensations. No tooth size-arch length
discrepancy was present in either arch. Both left and
right first molars showed a Class III dental relationship.
The patient appeared to have a relatively large
tongue; there was no family history of Class III
mandibular prognathism and facial asymmetry.

The original treatment plan included maxillary and
mandibular surgical intervention after presurgical orthodontic
treatment to extract the maxillary first premolars.
Maxillary surgery was refused because of the cost
and postoperative considerations. A compromise nonextraction
treatment plan was accepted with bilateral
sagittal split ramus osteotomy (BSSRO) and reduction
genioplasty. Surgical treatment was planned after the
maxillary occlusal plane cant had been corrected.

TREATMENT OBJECTIVES
The treatment objectives for this patient were to (1)
intrude the extruded teeth, (2) correct the canted maxillary
occlusal plane, (3) correct the midline shift, (4)
correct the posterior crossbite by expanding the narrow
maxillary arch, (5) correct facial asymmetry and mandibular
prognathism, and (6) improve facial appearance.

TREATMENT ALTERNATIVES
Generally, LeFort I osteotomy combined with mandibular
BSSRO is used for patients with canted occlusal
planes and facial asymmetry. Two maxillary first or
second premolars can be extracted to upright proclined
maxillary incisors and allow sufficient mandibular setback
before preorthodontic treatment..

Alternatively,
unilateral maxillary impaction of the extruded molar
area by segmental osteotomy can be used instead of
LeFort I osteotomy, but there are no common treatment
options for facial asymmetry that do not include surgery

TREATMENT PLAN
After review of treatment options, the patient accepted
the following treatment plan.
1. Extract all 4 third molars.
2. Bond both arches from second molar to second
molar.
3. Expand the maxillary dentition.
4. Decompensate with long Class III elastics.

5. To correct extruded teeth, implant miniscrews in
the maxillary left molar area, the mandibular left
molar area, and the right mandibular canine area.
6. Perform surgery, including BSSRO, with asymmetric
setback and reduction genioplasty.
7. Finish the occlusion after surgery.

TREATMENT PROGRESS
After extraction of the third molars, treatment
began by bonding both arches with 0.022 0.028-in
standard edgewise brackets. Initial leveling was accomplished
in 3 months with 0.016-in and 0.018-in round
nickel-titanium wires followed by 0.018 x 0.025-in
stainless steel archwires. A transpalatal arch was used
to assist in expanding the maxillary intermolar width.

Stainless steel wires (0.020 0.025 in) were
used with quarter-inch, 5-oz Class II elastics to decompensate
the maxillary and mandibular incisors .

Initially, four 8-mm miniscrews, with a
diameter of 1.2 mm, were
implanted in the left side of the maxilla and the
mandible between the second premolars and the first
molars, and between the first and second molars . The
miniscrews were implanted at chairside
under local anesthesia.

All miniscrews were implanted
with a pilot hole drilled with a 1-mm round bur
without incision of gingival tissue. Placement of the 4
miniscrews took approximately 15 minutes. Three
months after the first surgery, 2 more 8-mm miniscrews
were implanted between the maxillary left first and
second premolars (Fig 6, bottom row) and the mandibular
right canine and first premolar.

The miniscrew
between the mandibular right canine and first premolar
fractured during implantation, and a second miniscrew
of the same size was implanted just above the first site.

Elastics were used to intrude the teeth and
changed every 2 to 3 weeks. The intrusion of the left
molars took approximately 6 months; however, the
intrusion of the mandibular right canine required only 3
months. The intrusion achieved during treatment provided
sufficient space for the asymmetric mandibular
setback. The mandibular BSSRO and genioplasty were
performed .

Postoperative orthodontic treatment
took 5 months to finalize the patient’s occlusion.
The miniscrews were removed by the orthodontist
before the orthodontic treatment was completed. The
fractured miniscrew in the mandibular left canine
region was not removed then because of the difficulty
of removal. Ultimately, the failed implant was removed
by an oral surgeon after orthodontic finishing.

Retention
included fixed canine-to-canine lingual retainers in
both arches. Additionally, a maxillary circumferential
Hawley retainer was delivered for nighttime wear.
Gum-chewing also was recommended to assist in
preventing relapse of the intruded molars.

A, Postreatment cephalogram; B, superimposed tracings.

Posteroanterior cephalogram comparison: A, initial; B, before surgery, significant correction
of canted maxillary occlusal plane; C, final.

Maxillary advancement
with retroclination of maxillary anterior teeth
would have improved the midfacial profile and allowed
sufficient mandibular setback. The accepted alternative
of camouflage treatment without maxillary surgery
resulted in insufficient mandibular setback, so genioplasty
was added.

The patient showed clinically significant
improvement of facial asymmetry, even though he
had had only single-jaw surgery. We believe that a
better result would have been achieved with a 2-jaw
approach after the extraction of both maxillary first
premolars. Unfortunately, as for this patient, many
presumably ideal treatment plans must be modified.

Changing a canted occlusal plane requires either intrusion
of extruded molars or extrusion of intruded molars.
Extrusion of teeth can cause clockwise rotation
of the mandible, producing a longer face.
Correction of canted maxillary occlusal plane
with miniscrews.

Extrusion of teeth can cause clockwise rotation
of the mandible, producing a longer face. Intrusion
of molars is more stable and reduces facial height.
Because this patient would benefit from a reduction
in facial height, intrusion of molars was preferred.
Previous studies showed excellent intrusion of molars
by using skeletal anchorage with miniplates. For
our patient, miniscrews were chosen for skeletal anchorage.
The placement and removal of miniscrews
require less surgery and are easier than placement of
miniplates.

Because of the difficulty of placing miniscrews
between adjacent tooth roots, some doctors prefer
miniplates to miniscrews. Miniplates are used in the
zygomatic buttress area and midpalatal suture area
rather than the interdental area However, periapical
x-ray films taken by a parallel technique can be
useful to evaluate the space between roots
(a) Panoramic and (b) intra-oral pre-treatment
radiographs of the dentition as used to visualise the
interproximal area between the left maxillary second
premolar and first molar teeth. (c) The intra-oral radiograph is
repeated to confirm the position of a mini-implant in this site.

In dental
arches, the curve of Spee and mild root curvature of the
mandibular molars create larger interdental spaces between
the mandibular molars when compared with the
maxillary molars.

orthodontic correction of canted occlusal plane 2

orthodontic correction of canted occlusal plane 2

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