Arnet facial analysis

Journal club
soft tissue analysis
• Four parts will be presented
• Facial keys to orthodontic diagnosis and treatment planning. part I
• Facial keys to orthodontic diagnosis and treatment planning. part II
• Soft tissue cephalometric analysis; diagonsis and treatment planning
• The four stage treatment planning process for class II and classIII CASES
www.indiandentalacademy.com

Facial keys to orthodontic
diagnosis and treatment
planning..
Part I G. William Arnett, DDS and
Robert T. Bergman, DDS, MS
Santa Barbara, Calif

PURPOSE OF ARTICLE
(1) to present an organized, comprehensive
clinical facial analysis and
2 to discuss the soft tissue changes
associated with orthodontic and surgical
treatments of malocclusion.

• Patients are examined in natural head
position, centric relation, and relaxed lip
posture.
• Nineteen key facial traits are analyzed.

• Three questions are asked regarding the 19
facial traits before treatment:
• (1) What is the quality of the existing facial
traits?
• (2) How will orthodontic tooth movement to
correct the bite affect the existing traits
(positively or negatively)?
• (3) How will surgical bone movement to correct
the bite affect the existing traits (positively or
negatively)?

HISTORY
• Several lines and angles have been used
to evaluate soft tissue facial esthetics.

H -ANGLE
• . Ten degrees is ideal when the convexity
measurement is 0 mm.
• Holdaway said the ideal face has an H-
angle of 7° to 15°, which is dictated by the
patient's skeletal convexity

E-LINE

• Ricketts also described soft tissue by
relating beauty to mathematics. The divine
proportion was used by the ancient
Greeks (ratio of 1.0 to 1.618) and was
applied by Ricketts to describe optimal
facial esthetics.

•
• A patient with normal FMA, IMPA, FMIA,
and ANB measurements usually has a Z-
angle of 80° as an adult and 78° as a child
11 to 15 years of age.

Z-ANGLE

• Scheideman, Bell, et al. studied the
anteroposterior points on the soft tissue
profile below the nose.
•

Sn -vertical

• Worms and othersdiscussed lip
assessment for proportionality, interlabial
gap, lower face height, upper lip length,
and lower lip length.

• Another measurement used to study the
soft tissue is the angle of convexity
described by Legan and Burstone
• This is the angle formed by the soft tissue
glabella, subnasale, and soft tissue
pogonion.

• The zero meridian line, developed by
Gonzales-Ulloa, is a line perpendicular to
the Frankfort horizontal, passing through
the nasion soft tissue to measure the
position of the chin.
• The chin should lie on this line or just short
of it.

• The Steiner esthetic plane and the Riedel
plane have also been used to describe the
facial profile.

• It is widely accepted that orthodontic tooth
movement can alter esthetics
• Case believed the facial outline should be
regarded as an important guide in determining
treatment when correcting a malocclusion.
• He recommended extraction of teeth to retract
procumbent lips

• Angle related esthetics to the position of
the maxillary incisor.
• In evaluating facial beauty, Tweed
concentrated on the position and
inclination of the mandibular incisors in
relation to the basal bone.

• The soft tissue covering the teeth and
bone can vary so greatly that the
dentoskeletal pattern may be inadequate
in evaluating facial disharmony.
•

• Facial imbalance may be associated with
lip inadequacy or lip redundancy caused
by lip length, underlying tissues being out
of balance, or a problem in tissue
thickness o

• Burstone presented the idea that
correcting the dental discrepancy does not
necessarily treat the facial imbalance and
may even cause facial disharmonies.
•

• Drobocky studied 160 four first premolar
extraction patients and concluded that
"Ten to 15 percent of cases could be
defined as excessively flat (dished-in) after
treatment.“
• Park and Burstone23 studied 30 cases in
which the lower incisor was 1.5 mm
anterior to the A-Pog line .

• This relationship is proposed by some
orthodontists as the key to an esthetic
profile.
• The profiles of these 30 patients were
found to be grossly different therefore
casting doubt on the reliability of the
incisor-to-A-Pog line as a reliable esthetic
guideline.

LIMITATION OF
CEPHALOMETRICS
• Another source of cephalometric
inadequacy in facial diagnosis and
treatment planning is the cranial base.
• When the cranial base is used as the
reference line to measure the facial profile,
bogus findings can be generated.

• Michiels studied 27 nonorthodontic, Class I
patients to test the validity of various popular
cephalometric measurements used to predict
clinical profiles. His conclusions were that
• (1) measurements involving cranial base
landmarks are inaccurate in defining the actual
clinical profile;

• 2) measurements involving intrajaw
relationships were slightly more accurate
in reflecting the true profile;
• (3) no measurement is 100% accurate;
and
• (4) the soft tissue thickness and axial
inclination of incisors are the most
important variables in inaccuracy.

• Wylie analyzed 10 patients using five
popular cephalometric analyses and found
only 40% agreement on treatment
planning. He concluded that
"cephalometrics should not be the primary
diagnostic tool for dentofacial diagnosis.“
•

• Many cephalometric norms have been
based on patient populations that had no
skeletal disharmonies. When these
"normal values" from normal populations
are applied to anterioposterior and vertical
skeletal disharmonies they lose validity.

• Further problems with cephalometric
diagnosis relate to the anatomic areas
studied.

• Facial analyses developed with
cephalometric x-ray films, such as those
by Holdaway, Merrifield,Burstone,and
others, focused primarily on
anterioposterior orthodontically alterable
dimensions of the face.
•

• Complete analysis requires incorporation
of vertical and transverse assessment of
bite and facial needs.

• Still another problem with cephalometric
diagnosis and treatment planning is that
the norms may not be accurate because
of different soft tissue posturing.
• In some studies, the soft tissues were not
in a repose position when measurements
were made

• This is particularly disruptive in the vertical
dimension. Vertical skeletal diagnosis
depends on assessment of the soft
tissues in repose.
• Because early studies examined the
patient in the closed lip position, reliable
norms for relaxed lip position may be
lacking.

• Closed lip position may be useful when no
skeletal deformity exists, but in the case of
skeletal deformity the closed lip posture is
not accurate in terms of diagnosis and
treatment planning.

• Burstone and others noted that nose
length, lip length, and nasolabial angle are
important aspects of facial esthetics .

• Models, cephalometrics and facial
analysis together should provide the
cornerstones of successful diagnosis
• .

• Models and/or clinical bite examination
indicate to the practitioner that bite
correction is necessary.
• Facial analysis should be used to identify
positive and negative facial traits and
therefore how the bite should be corrected
to optimize facial change needs.

FACIAL KEYS TO ORTHODONTIC
DIAGONOSIS
• In this system, the cephalometric x-ray film
is not used for diagnosis, but rather as an
aid to try treatment options in the form of
visual treatment objectives (VTO).
•

• The purpose of the VTO is to assess how
tooth and bone movement used to correct
the bite will impact the face.

• An example of this is correcting a Class II
occlusion with either a LeFort I impaction,
mandibular advancement, or upper first
premolar extractions with headgear and
Class II elastics. All three treatments
correct the bite but change the face in
different ways.

• The procedure selected should balance
the face optimally. Facial examination can
determine the best treatment for achieving
facial balance, whereas cephalometric
analysis has been shown to be unreliable.

• The most important point in proper
analysis of facial esthetics is the use of a
clinical format.

• Natural head posture,
• centric relation (uppermost condyle
position),
• and relaxed lip posture
•

• Natural head posture is preferred because
of its demonstrated accuracy over
intracranial landmarks.
• Natural head posture has a 2° standard
deviation compared with a 4° to 6°
standard deviation for the various
intracranial landmarks in use

• Natural head posture is the head
orientation the patient assumes naturally
• . Patients do not carry their heads with the
Frankfort horizontal parallel to the floor.
• Therefore this landmark should not
dictate head posture used for treatment
planning.

• When skeletal changes are made relative
to natural head position appropriateness is
ensured in the resulting soft tissue profile.

CENTRIC RELATION
• All examination data should be recorded in
centric relation since orthodontic and
surgical results are strictly in this position
to produce precise function
• If head films are taken in a postured
position, all interarch relationships are
incorrect.

• Posturing of the mandible can decrease
the severity of Class II
• can increase the severity of Class III
relationships .

Class II CASE

CLASS III CASE

Centric relation can be established as follows
• 1. Patient in a 45° sitting position.
• 2. Use a warmed, double-thickness piece
of pink base plate wax.
• 3. Guide the opening and closing to first
tooth contact, nondeflected position.

• . The wax bite is used for head films,
tomograms, model mounting, and facial
analysis. This ensures consistency of data
and treatment results.

RELAXED LIP POSITION
--------------------------------
The relaxed lip position is obtained while the
patient is in centric relation by the following
method
1. Ask the patient to relax.
2. Stroke the lips gently.
3. Take multiple measurements on different
occasions.
4. Use casual observation while the patient is
unaware of being observed.

• The patient should be in the relaxed lip
position because it demonstrates the soft
tissue, relative to hard tissue, without
muscular compensation for dentoskeletal
abnormalities.

• Vertical disharmony between lip lengths
and skeletal height (vertical maxillary
excess, vertical maxillary deficiency,
mandibular protrusion, mandibular
retrusion with deep bite) can not be
assessed without the relaxed lip posture.

• Existing positions and needed changes in
upper incisor exposure, interlabial gap, lip
length, and proportion are lost in the
closed lip position.
• Closed lip position may be adequate for
normoskeletal cases but is totally
inadequate for skeletal disharmony
assessment

• When the lips contact (distortion), the bite
should be opened by placing a wax bite
between the teeth until the lips separate in
the repose posture.
• By using this open bite posturing, lip
length and position distortion is avoided.
Soft tissue cosmetic problems can then be
assessed relative to needed bite changes.

OPENING THE BITE TO ACCESS
LIP LENGTHS

ASSESSMENT OF OPEN BITE

• With the natural head posture, centric
relation, and relaxed lip position, the
patient is visualized in all three planes of
space:
• 1. Anterior-posterior
• 2. Transverse
• 3. Vertical

• This examination consists of 19 of these traits.
• Inclusion of a trait within the study was
dependent on the high significance of the trait to
successful orthodontic and surgical facial
outcomes.
• Examination of key traits in three planes of
space was necessary. The normal values are a
combination of previous studies and 20 years of
surgical experience.

DIFFERENT VALUES FOR SAME
TRAIT
• An example of the
variability is the
nasolabial angle
BURSTONE 73.8+_ 8
LEGAN 102+- 8
FARAKAS 99.1+-8.7

Many reasons exist for the inconsistency between
different study norms (Table II), including the
following
: --------------------------------
1. Different racial origins within the study
populations.
2. Some studies contained malocclusions,
whereas some studies had normal bites or
Class I occlusions only.
3. Some studies were in closed lip
positions, whereas others were in relaxed
lip position.

• 4. Some studies used head films oriented to
cranial base structures, others were in natural
head position.
• 5. Some values were from clinical measurement,
although most were from cephalometric x-ray
films.
• 6. The exact way of measuring the same trait
may be different from one study to the next.
• 7. Some studies contained patients who were
not fully grown.

• Due to the discrepancy of norms, each
patient being examined should be studied
with norms appropriate to that patient
(race, age, lip posture, head orientation).

--------------------------------
By asking the following three questions, the best
treatment plan becomes apparent:
• --------------------------------
• 1. What is the quality (good or bad) of the
existing facial traits?
• 2. How will the orthodontic tooth
movement to correct the bite affect the
existing traits (positively or negatively)?
•

• 3. When surgery is necessary, which
surgery (maxilla, mandible, or both) will be
necessary to normalize negative and
maintain positive facial traits while
correcting the bite

• Four possible treatments exist for each patient:
• (1) orthodontics alone
• , (2) orthodontics plus lower jaw surgery,
• (3) orthodontics plus upper jaw surgery and
• (4) orthodontics plus both upper and lower jaw
surgery.
• The treatment that optimizes occlusion (bite and
TMJ harmony), facial balance, stability, and
periodontal health is chosen. If treatment harms
the patient, it should not be rendered.

• Nineteen facial traits were selected for this
examination
• . Two views of the patient are used for
identification of problems in three planes
of space:

• I. Frontal
A. Relaxed lip
B. Functional analysis
1. Closed lip
2. Smile
• II. Profile
A. Relaxed lip

FRONTAL VIEW
• Natural head posture,
• centric relation,
• and relaxed lip posture are used to
accurately assess the frontal view.

--------------------------------
Outline form and symmetry
• 1 The widest dimension of the face is the
zygomatic width
• The bigonial width is approximately 30%
less than the bizygomatic dimension.
•

• Farkas has established normal values for
height and width.
• The height to width proportion is
• 1.3:1 for females
• and 1.35:1 for males.
•

• An alternative to measuring height and
width is to artistically describe the face.
Faces are wide or narrow, short or long,
round or oval, square or rectangular.

Frontal view

• Will orthodontic and/or surgical care necessary
for bite correction correct or accentuate existing
height and width imbalance?
• An example of orthodontic correction of height-
width imbalance is the use of bite opening
mechanics to lengthen the face during bite
correction.
• An example of surgical correction is maxillary
impaction to shorten the long face.

• The extremes of disproportion are short
and wide or long and narrow.
• Short, square facial outlines are indicative
of deep bite Class II malocclusion, vertical
maxillary deficiency, and in some cases,
masseteric hyperplasia.
•

• Long, narrow faces are associated with
vertical maxillary excess or mandibular
protrusion with dental interferences
leading to open bite.
• The bizygomatic dimension is often
deficient (cheekbone deficiency) in
combination with maxillary retrusion.
• The bigonial dimension may be deficient
in combination with mandibular retrusion.

• Height and width disproportion is
corrected in two ways:
• 1. Maxillary or mandibular surgery is used
simultaneously to correct the bite and to
lengthen or shorten the facial height.
• 2. Augmentation or reduction of the facial
height or width

• Examples of the latter are
• chin lengthening to increase facial height (H to
Me'),
• cheekbone augmentation to increase the
bizygomatic width (Zy to Zy),
• or augmentation of the mandibular angles to
increase the bigonial dimension (Go' to Go').
• Buccal lipectomies can help reduce excessive
width in the submalar cheek areas.

• --------------------------------
• As a general rule, the maxilla should rarely
be moved up and back.
• This movement decreases lip support,
increases the nasolabial folds, decreases
incisor exposure, and can make the facial
outline appear short and wide.
• These changes give the appearance of
premature facial aging.

ASSYMETRY
• The most common to least common sites
of facial asymmetry are
• chin, mandibular angles, and
cheekbones.

• Correction of asymmetries are
accomplished with
• (1) cant correction or midline movement of
the maxilla and mandible simultaneous
with occlusal correction or
• (2) augmentation or reduction of the
skeletal surfaces.

• Examples of the latter include unilateral
cheekbone, angle, or body augmentation.
• A common asymmetry correction is chin
shifting to the right or left to center the chin
on the facial midline.

FACIAL LEVEL
• To examine facial levels a reliable horizontal
landmark line is necessary.
• With the patient in natural head posture, the
pupils are assessed for level with the horizon.
•
• Structures compared with the pupil line are
• (1) upper canine level,
• (2) lower canine level, and
• (3) chin and jaw level.

--------------------------------
Facial level

• --------------------------------
• If the pupils, in natural head posture, are not
level to the horizon, a constructed frontal
horizontal reference line is used. This line is
visualized as follows:
• 1. Frontal natural head posture.
• 2. Horizontal line parallel to the horizon through
the pupil area.
• 3. Assess other structures relative to this line

Midline alignments
• Midlines are assessed with uppermost
condyle position and first tooth contact.
• If occlusal slides alter joint position, no
reliable midline assessment can be made.
•

• The relative positions of soft tissue
landmarks (nasal bridge, nasal tip, filtrum,
chin point) and dental midline landmarks
(upper incisor midline, lower incisor
midline) are noted.

• . Filtrum is usually a reliable midline
structure and can be used as the basis for
midline assessment most often.
• When the pupils are level in natural head
posture, a vertical line through filtrum
midpoint is used to assess other hard and
soft tissue midline structures

Pupils not aligned

• Dental midline shifts are the result of multiple
dental factors including:
• 1. Spaces
• 2. Tooth rotations
• 3. Missing teeth
• 4. Buccally or lingually positioned teeth
• 5. Crowns or fillings which change tooth mass
• 6. Congenital tooth mass difference from left to
right

• Dental midline shifts are treated
orthodontically.
• Asymmetric premolar extractions may be
necessary to align dental and skeletal
midlines.
• Skeletal midline shifts are not corrected
orthodontically, surgery is employed.

• When the dental and skeletal midlines deviate
together, the etiologic factor is usually skeletal,
and surgery is used to correct (i.e., chin and
lower incisor midline are 3 mm to the left).
• . Attempts to orthodontically correct the bite
when the etiologic factor is skeletal can produce
buccal plate violation and gingival recession

Facial one thirds
The face divides vertically into thirds
from hairline to midbrow, midbrow to
subnasale, and subnasale to soft
tissue menton
(. The thirds are within a range of 55
to 65 mm, vertically

The hairline is variable, and the upper third is
frequently low range.
Increased lower one-third height is frequently
found with vertical maxillary excess and Class III
malocclusions (lack of interdigitation opens
vertical height).
Decreased lower one-third height is associated
with vertical maxillary deficiency and mandibular
retrusion deep bites.

• Production of correct proportion influences
the choice of surgical procedure used to
correct the occlusion (i.e., maxillary
impaction to correct Class II malocclusion
associated with long lower one-third rather
than mandibular advancement).

• The equality of the middle and the lower
thirds should not be used as the
determining factor in facial height
changes.
• The appearance of the landmarks (incisor
exposure, interlabial gap) within the lower
third are more important in assessing
balance than are the equality of the thirds

Lower third

--------------------------------
Lower one-third evaluation
• Upper and lower lip lengths
• The lips are measured independently in a relaxed
position .
• The normal length from subnasale to upper lip inferior is
19 to 22 mm.
• If the upper lip is anatomically short ( 18 mm or less), an
increased interlabial gap and incisor exposure is seen
with a normal lower face height.
•

• This should not be confused with vertical
maxillary excess (increased interlabial
gap, increased upper incisor exposure,
increased lower one-third facial height).

• The lower lip is measured from lower lip
superior to soft tissue menton and
normally measures in a range of 38 to 44
mm.
•
• (lower incisor tip to hard tissue menton;
• women, 40 mm ± 2 mm,
• and men, 44 mm ± 2 mm).

• Anatomic short lower lip should not be
confused with a short lower lip secondary
to posture (upper incisor interferences)
seen in Class II deep bite cases with
normal anterior dental height.
• Anatomic short lower lip can be
lengthened with a lengthening genioplasty.

• anatomic long lower lip can be associated
with Class III malocclusions.
• This should be verified with the
cephalometric anterior dental height
measurement.

• A closed lip position will produce a long
lower lip in combination with increased
lower facial height (vertical maxillary
excess and Class III) as the lip elongates
to close.
• The closed lip length is misleading and
should not be used for treatment planning.
• The normal ratio of upper to lower lip is
1:2.

• Lip redundancy is seen in cases of vertical
maxillary deficiency and mandibular
retrusion with deep bite and, rarely, long
lip lengths.
• To accurately assess lip lengths with
redundant lips, the patient's bite must be
opened until the lips separate

Upper lip to incisal edge

Upper tooth to lip relationship
• . The distance from upper lip inferior to maxillary incisal
edge is measured .
• The normal range is 1 to 5 mm.
• Women show more within this range.
• Surgical and orthodontic vertical changes are based
primarily on this measurement (i.e., postsurgical incisor
exposure range of 1 to 5 mm).
• Conditions of disharmony are produced by four
variables:

• Conditions of disharmony are produced by four
variables:
• 1. Increased or decreased anatomic upper lip
length (infrequently).
• 2. Increased or decreased maxillary skeletal
length (frequently).
• 3. Thick upper lips expose less incisor than thin
upper lips, all other factors being equal.

• 4. The angle of view changes the amount
of incisor visible to the viewer.
•

• overimpaction of upper incisor teeth leads
to the appearance of premature aging,
especially in conjunction with maxillary
retraction.
• This type of surgical movement is rarely
indicated.
•

• Posterior movement of the maxillary
incisors is indicated only for true maxillary
protrusion.
• Orthodontic overretraction, which is used
to occlusally correct mandibular retrusion,
produces premature aging of the face.

Interlabial gap
• . With the lips relaxed, a space of 1 to 5
mm between upper lip inferior and lower
lip superior is present
• . Females show a larger gap within the
normal range.
• This measurement is also dependent on
lip lengths and vertical dentoskeletal
height.

• Increases in interlabial gap are seen with
• anatomic short upper lip,
• vertical maxillary excess,
• and mandibular protrusion with open bite
secondary to cusp interferences.
•

• Decreased interlabial gap is found with
vertical maxillary deficiency,
• anatomically long upper lip (natural
change with aging, especially in males),
• and mandibular retrusion with deep bite.

• Abnormalities should be considered when
planning skeletal changes.
• An anatomically short upper lip should be
recognized as a soft tissue problem and
should not be treated by excessively
shortening the maxilla.
• This can lead to a short, round facial
outline.

Closed lip position.
• Even though an understanding of relaxed
lip position is essential, an understanding
of closed lip position adds support to
diagnostic patterns. The closed lip position
also reveals disharmony between skeletal
and soft tissue lengths.

• Increased mentalis contraction (mentalis
strain), lip strain, and alar base narrowing
are observed in vertical skeletal excess,
anatomic short upper lip and some cases
of mandibular protrusion with open bite.

Smile position lip level
• When examining the smile posture,
different lip elevations are observed in
normal and abnormal skeletal patterns.
• Ideal exposure with smile is three-
quarters of the crown height to 2 mm of
gingiva, females more than males.

• 1 Variability in gingival exposure is related
to
• (1) lip length,
• (2) vertical maxillary length,
• (3) maxillary anatomic crown length,
• and (4) magnitude of lip elevation with
smile.

• Because of etiologic variability, surgical
shortening of the maxilla is indicated only
when excess gingival exposure is found in
combination with increased interlabial gap,
increased tooth exposure, increased lower
face height, and/or mentalis strain.

• Deficient exposure etiologic factors
include a
• long upper lip,
• vertical maxillary deficiency,
• and/or minimal smile lip elevation
• .

• Decreased incisor exposure is treated with
maxillary lengthening when found in
combination with decreased interlabial gap
-lip redundancy,
• short lower one-third face height,
• and normal upper lip length.

• When impacting or lengthening the maxilla on
the basis of reposed incisor exposure, gingival
smile exposure should also be considered.
For example, if the patient has normal smile
gingival exposure (1 to 2 mm) and the incisors
are lengthened to treat decreased relaxed lip
incisor exposure, excessive smile gingival
exposure will result

• Particular care should be taken with short clinical
crowns.
• A 3 to 4 mm repose incisor exposure may
expose unacceptable amounts of gingiva when
smiling because of short maxillary incisor
crowns.
• This situation is properly treated by placing
normal length crowns (veneers) on the maxillary
incisors and treatment planning from the repose
and smile perspective.

PROFILE VIEW
• Natural head posture, centric relation, and
relaxed lips are used to accurately assess
profile.

Profile angle

• This angle is formed by connecting soft tissue
glabella, subnasale, and soft tissue pogonion
• General harmony of the forehead, midface, and
lower face is appraised with this angle.
• Maxillary and mandibular basal bone
anteroposterior discrepancies are easily
visualized.

• Class I occlusion presents a total facial
angle range of 165° to 175°.
• Class II angles are less than 165°,
•
• and Class III are greater than 175°

• Skeletal discrepancies producing Class II
angulation include maxillary protrusion
(rare), vertical maxillary excess (common),
and mandibular retrusion (common).
• Class III skeletal patterns include maxillary
retrusion (common), vertical maxillary
deficiency (rare), and mandibular
protrusion (common).

• . The profile angle is the most important key to the need
for anteroposterior surgical correction.
• When values are less than 165° or greater than 175°,
skeletal malocclusions needing surgery are probably the
cause.
• Angles at the extreme of normal (greater than 175° or
less than 165°) are usually caused by skeletal
disharmony.
• Soft tissue thickness differences are not capable of
causing these extreme angle changes.

Nasolabial angle

• This angle is formed by the intersection of
the upper lip anterior and columella at
subnasale
• This angle can change noticeably with
orthodontic and surgical procedures that
alter the anteroposterior position or
inclination of the maxillary anterior teeth

• . All procedures should place this angle in
the cosmetically desirable range of 85° to
105°.
• Female patients will usually be more
obtuse within this range. :

Factors to be considered in treatment
planning to correctly achieve this angle are
as follows
1.Existing angle.
2. Tilting versus bodily movement of maxillary teeth
(orthodontic and surgical) and predicted effect on
the existing lip position.
3.

• Estimation of lip tension present.
• Tense lips may move more posteriorly
with tooth and basal bone movement and
less anteriorly.
• Flaccid lips may move less with posterior
tooth and basal bone movement and less
with anterior.

• 4. Anteroposterior lip thickness
• .
• Thin lips (6 to 10 mm) may move more
with tooth retraction movement than thick
lips (12 to 20 mm).

OVERJET
• The magnitude of the mandibular retrusion
(overjet).
• the larger the overjet distance, the more
retraction of the maxillary incisors will be
necessary, thus opening the nasolabial
angle.

• 6. The following factors affect the
anteroposterior movement of incisor teeth after
extractions:
• Amount of anterior crowding,
• spaces,
• tooth mass proportion (upper versus lower),
• posterior rotations,
• curve of Spee (upper versus lower),
• and anchorage (headgear, Class II elastics).

7. Extraction versus nonextraction.
8. Extraction pattern (first versus
second premolars).

• If the nasolabial angle is open (approximately 105°),
• retraction of anterior teeth orthodontically and surgically
should be avoided in treatment planning.
• Likewise, a long nose will become adversely prominent
with lip retraction.
• Present limited knowledge of how lips respond to
anteroposterior movement of the teeth dictates a
conservative approach when large movements are
contemplated.

• .
• As a general rule, the maxilla should not
be moved posteriorly in treating
dentofacial deformities, especially in
combination with superior repositioning.

• This creates nasal elongation, alar base
depression, and opening of the nasolabial
angle, all of which create facial premature
aging..

Maxillary sulcus contour

• Maxillary sulcus contour (MxSC) is
subjectively assessed. The contour is
described as either
• accentuated,
• gentle curve (normal)
• or flat.
• Measurement of this contour is
impractical.

• Normally this sulcus is gently curved and gives
information regarding upper lip tension
• . With lip tension, the sulcus contour flattens.
• Flaccid lips form an accentuated curve with the
vermilion lip area showing an accentuation of
curve
• .

• The flaccid lip generally is thick (12 to 20
mm from anterior vermilion to labial
incisor) giving the lip (i.e., headgear with
Class II elastics or functional appliance
treatment) the appearance of being too far
forward relative to the teeth

• The maxilla should not be retracted
significantly when a deeply curved, thick
lip is present since this produces poor lip
support and cosmetics.
• If possible, the maxilla should be moved
forward into a thick, curved lip to improve
lip support.

Mandibular sulcus contour

Mandibular sulcus contour (MdSC) is
subjectively assessed.
The contour is either
accentuated,
gentle curve (normal)
or flat.
Measurement of this contour is impractical.

• Orbital rim projection is measured from
the anterior most globe (Gb) to the orbital
rim point (OR). A subjective orbital rim
description is also given: Normal, flat, or
protruded.

• The orbital rim is an anteroposterior
indicator of maxillary position. Deficient
orbital rims may correlate positionally with
a retruded maxillary position because the
osseous structures are often deficient as
groups, rather than in isolation..

• The globe normally is positioned 2 to 4
mm anterior to the orbital rim
• The surgical maxillary versus mandibular
decision is influenced by the orbital rim
position. Deficient orbital rims dictate
maxillary advancement, all other factors
being equal

Cheekbone contour

• Cheekbone contour is anteriorly facing,
curved line that starts just anterior to ear,
extending forward through cheekbone
point (CP), then extending anterior-
inferiorly ending at maxilla point (MxP)
adjacent to alar base of nose.

• For descriptive purposes the cheekbone
contour is divided into three areas: (1)
zygomatic arch, (2) middle contour area,
and (3) subpupil areas.

• The CP is located 20 to 25 mm inferior
and 5 to 10 mm anterior to the outer
canthus (OC) of the eye when viewed in
profile . When viewed frontally the CP is
20 to 25 mm inferior and 5 to 10 mm
lateral to the OC .

• . CP and MxP indicates osseous
cheekbone and maxillary base positions,
respectively.

• The nasal base-lip contour (Nb-LC)
extends inferiorly from the maxilla point
(MxP) as a gentle, anteriorly facing curve,
ending just below and lateral to the mouth
commissure.

• In normoskeletal patients the cheekbone-
nasal base-lip contour complex is a
smooth continuation, anteriorly facing,
curved line.
• This line, when viewed frontally or from
the side, is a definite flowing curve with no
interruptions which are apparent with
skeletal deformities.

• Maxillary retrusion is indicated by a
straight or concave contour at MxP . When
this anatomic area is concave or flat,
maxillary advancement is necessary.

•Mandibular protrusion interrupts the
nasal base-lip line in the length of the
upper lip (F When the line is interrupted
within the height of the upper lip a
mandibular setback may be indicated.

NASAL ROJECTION
• The nasal projection (NP) measured
horizontally from subnasale to nasal tip is
normally 16 to 20 mm
• Nasal projection is an indicator of
maxillary anteroposterior position.

throat length and contour
• The distance from the neck-throat junction
to the soft tissue menton should be noted .
• No millimeter measurement is necessary,
but a planned mandibular setback will
change this length. The predicted esthetic
result should produce a normal appearing
length without sagging.

• This length becomes particularly important
when contemplating anterior movement of
the maxilla.
• Decreased nasal projection
contraindicates maxillary advancement.
With a Class III malocclusion, short nose,
and all other factors equal, mandibular
setback is indicated.

• Throat length (TL) is assessed from neck-
throat point (NTP) to soft tissue menton
(Me'). This distance is subjectively
described as either normal, long or short
length, and with or without sag.

• A patient with a short, sagging throat
length is not a good candidate for
mandibular setback. A long, straight throat
length is amenable to mandibular setback.

• Often a mandibular setback is necessary
with chin augmentation to balance lips
with chin and maintain throat length.
• Suction lipectomy is a useful adjunct for
controlling submental sag with setbacks or
when isolated fat accumulation is present.

• . Subnasale-pogonion reference line is
generated through points subnasale (Sn)
and soft tissue pogonion (Pg'). Lip
projections are evaluated relative to this
line.

Subnasale-pogonion line
• (Sn-Pg')
• Burstone reported that the upper lip is in
front of the Sn-Pg' line by 3.5 mm ± 1.4
mm, and the lower lip is in front of the line
by 2.2 mm ± 1.6 mm.16

• The relationship of the lips to the Sn-Pg'
line is an important aid in orthodontic soft
tissue analysis and treatment. Tooth
movement changes the relationship of the
lips to the Sn-Pg' line and therefore the
esthetic result.
• All tooth movements should be assessed
in regard to the anticipated lip change to
the Sn-Pg' line.

• Extractions should be avoided when they
move the teeth and create retraction of the
lips (dished-in) behind this line The
relationship of the lips to this line is
affected by the following factors:

• 1. Skeletal relationship: When anterior or
posterior skeletal disharmony exists, producing
overjet abnormalities (positive or negative), the
Sn-Pg' has no validity.
• 2. Incisor inclinations: With a Class I skeletal
pattern, the upper and lower incisors must be at
proper overjet and axial inclination to produce
proper protrusion of the lips relative to the Sn-
Pg' line.

• 3. Lip thickness: The lip relationship to the
Sn-Pg' line is dependent on lip thickness.
The Burstone relationship16 is true only if
the lips are the same thickness, all other
factors being ideal..

• Class I incisors (upper incisor in front of
lower incisor) produce Class I lips (upper
lip in front of lower lip) only if the lips are of
equal thickness

• This line is also used when planning
surgery on the VTO
• The Sn-Pg' line is ideally drawn to the lips
through subnasale. If Pg' is significantly
posterior to the line, a chin augmentation
is indicated. Female chins are softer
relative to this line.

SOFT TISSUE CHARACTERISTICS OF
COMMON SKELETAL DEFORMITIES
• With the 19 facial keys, 8 pure skeletal
deformities with predictable soft tissue
appearances can be defined.
• The greater magnitude of the skeletal
deformity the more distinct the soft tissue
pattern.
•

• Skeletal deformities may occur in
combination (i.e., vertical maxillary excess
with mandibular prognathism) and facial
traits are therefore blended. I
• in all cases, facial traits are helpful in
diagnosing skeletal problems. The eight
uncombined or pure or unmixed
anteroposterior facial-skeletal types are as
follows:

• A. Class I facial and dental (facial angle
Class I)
• 1. Vertical maxillary excess
• 2. Vertical maxillary deficiency

Class I occlusion and chin projection can
occur in combination with vertical maxillary
excess or vertical maxillary deficiency.
The anteroposterior profile is normal, but
the vertical height of the face is long or
short.

B. Class II facial and dental (facial
angle
3. Maxillary protrusion
4. Vertical maxillary excess
5. Mandibular retrusionwww.indiandentalacademy.com

• . Class II bite and chin projection can be
produced by entirely different skeletal
patterns.
• axillary protrusion, mandibular retrusion
and vertical maxillary excess all can
produce identical bites with similar chin
profiles.

• C. Class III facial and dental (facial angle
Class III)
• 6. Maxillary retrusioin
• 7. Vertical maxillary deficiency
• 8. Mandibular protrusion

ORTHODONTIC PREPARATION FOR
SURGERY
--------------------------------
Extraction patterns and mechanics are aimed
at removing dental compensations before
surgery.
Compensation removal leads to better facial
results. An example of this is a 10 mm
skeletal mandibular retrusion. Incisor dental
compensations to the overjet may decrease
the 10 mm overjet to 5 mm.

If the mandible is advanced with the
compensations present, the chin
deficiency is still 5 mm. In contrast, when
dental compensations are removed, the
10 mm overjet and 10 mm chin retrusion
are simultaneously and totally corrected
with surgical advancement.
•

• The most common appropriate extractions
for routine facial-skeletal deformities are
as follows:
• A. Class I facial and dental (chin in
balance with the face)
• 1. Vertical maxillary excess— variable
• 2. Vertical maxillary deficiency— variable

• B. Class II facial and dental (chin retruded)
• 1. Maxillary protrusion— lower second
and/or upper first premolars, orthodontic
correction. No surgery required.
• 2

• . Vertical maxillary excess— upper
extraction based on extent and location of
crowding, lower extraction based on
effects on upper lip support when LeFort I
is done to correct vertical maxillary
excess.
• 3. Mandibular retrusion— upper second
premolar and/or lower first premolars

• C. Class III facial and dental (chin
protruded)
• 1. Maxillary retrusion— upper first and
lower second premolars
• 2. Vertical maxillary deficiency— upper
first and lower second premolars
• 3. Mandibular protrusion— upper first and
lower second premolars

• An additional benefit of the surgical
extraction pattern is that the anticipated
surgical relapse becomes the opposite of
the orthodontic relapse pattern

• . An example of this is mandibular
advancement with lower first premolar
extractions that have uprighted the lower
incisors.

• Surgical relapse is posterior, and
orthodontic relapse at the lower incisors is
anterior, in the opposite direction. The
orthodontic relapse is a mechanism to
compensate for surgical relapse.

Arnet facial analysis

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