Smile esthetics in othodontics. /certified fixed orthodontic courses by Indian dental academy
Smile esthetics in orthodontics
INDIAN DENTAL ACADEMY
Leader in continuing dental education
Records in treatment of the smile
The social smile and the enjoyment smile.
Analysis of the smile in 4 dimensions.
(Frontal, Sagittal, Oblique, Time-specific.)
extractions on smile esthetics
Tooth shape and smile esthetics
Principles of cosmetic dentistry in smile
Maxillary midline diastema.
The importance of beauty and attractiveness
in today’s society has been well established.
Physically attractive people are perceived to
be more kind, sensitive, interesting, strong,
poised, modest, sociable, outgoing, exciting,
and responsive. (Dion et al 1972)
It is also believed that attractive people are
more likely to obtain better jobs,have more
successful marriages, and experience
happier,more fulfilling lives.
These societal biases begin early in life and
impact a person’s future for a lifetime.
attractiveness is particularly
important to a person’s psychosocial
People with a normal dental
appearance are judged more socially
attractive over many personal
characteristics than those with
malocclusions. (Shaw et al AJO 1985)
Those with poor dental esthetics have
been linked to lack of self-confidence
and are thought to be disadvantaged in
social, educational, and occupational
interpersonal interactions, the
eyes primarily scan other people’s eyes
and mouths, with little time spent on
other features. (Miller, 1970)
Thus it is not surprising that the general
public considers the smile to rank
second only to the eyes when
considering features most important to
facial esthetics. (Goldstein, 1969)
Tatarunaite et al (AJODO 2005)
reported that smiling and youthful facial
appearance make women look more
Esthetics, which is derived from the Greek word
for perception, deals with beauty and the beautiful.
It may be divided into two dimensions: objective
(admirable) and subjective (enjoyable ) beauty.
Objective beauty implies that the object possesses
properties that make it unmistakably praiseworthy.
Subjective beauty is value laden, and is related to
the tastes of the person contemplating it.
should lend objective esthetics to the entire
orofacial complex involving unity, form,
color, function and display of the dentition.
In addition, the creation of subjective
beauty according to the orthodontist‟s own
preferences may enhance the cosmetic value
of treatment given to each patient.
Esthetics in orthodontics has been
defined mainly in terms of profile
enhancement, but if you ask lay people
what an orthodontist does, their
answers will usually include something
about creating beautiful smiles.
study of frontal facial form dates
back to the Egyptians, who depicted
ideal facial esthetics as the ―golden
proportion.‖ This concept has been
described extensively in classical art
and orthodontic literature.
In the latter part of the 19th
Kingsley, the leading
orthodontist of the
era, emphasized the esthetic
objectives of orthodontic
In the Kingsley
paradigm, the articulation of
the teeth was clearly
secondary to facial
Edward Angle‟s emphasis on occlusion led him to
teach that optimal facial esthetics always
coincided with ideal occlusion and that esthetics
could essentially be disregarded because it took
care of itself.
Classification schemes were based on static
morphologic features, such as molar
relationships and the extent of facial
Also, the early concepts of esthetics revolved
largely around the patient’s profile, and it was
believed that, once the ―ideal‖ tooth–jaw
positions were achieved, then the soft tissues
would fall in line.
This focus on the profile was because the
lateral cephalogram has long been the
lynchpin of orthodontic treatment planning.
As a result, orthodontics tended to drift away
from clinical examination of the patient and
the art of physical diagnosis.
There is little debate about the many
advancements that Angle made in
orthodontics, most notably his system of
But perhaps more attention should be paid to
his inclusion of art in the orthodontic search
for quantifying facial beauty.
Art instruction by Prof Wuerpel was an
integral part of the Angle curriculum, but it
has gradually disappeared from the modern
When orthognathic surgery developed in the
1970s and growth modification treatment
reappeared for children, the goal was to obtain
better occlusion more than better facial
In the 1980s, the introduction of new esthetic
materials in restorative dentistry led to the
widespread adoption of “esthetic dentistry.”
At about the same time, it became clearer to all
involved that orthognathic surgical goal setting
was esthetically www.indiandentalacademy.com
The esthetic paradigm
Although ideal occlusion remained the primary
functional goal, it was acknowledged that the
esthetic outcome was critical for patient
This has led to the emergence of the esthetic
paradigm in orthodontic treatment.
A paradigm can be thought of as “ a set of shared
beliefs and assumptions that represent the
conceptual foundation for an area of science or
―art of the smile‖ is being driven
by the orthodontist’s ability to clinically
examine the patient in 3 dimensions
and use the latest technology (computer
databasing of the clinical examination
and digital videography) to document,
define, and communicate the treatment
strategy to patients and colleagues
involved in interdisciplinary care.
contemporary orthodontist no
longer evaluates patients in terms of
only the profile, but also frontally and
vertically, to complete the 3 spatial
dimensions, and statically and
Also, the orthodontist must now add a
fourth dimension: Time
are the first in line in a
decision-making process that ultimately
affects a patient’s appearance for the
rest of his or her life.
The orthodontist must understand not
only dentoskeletal growth and
development, but also soft tissue
growth, maturation, and aging.
orthodontist must work with 2
A. Soft tissue repose and animation
assessed at the patient’s examination
including how the lips animate on smile,
gingival display, crown length, and other
attributes of the smile.
B. Facial change throughout a patient’s
lifetime: the impact of skeletal and soft
tissue maturational and aging
characteristics, which are well
Records in the treatment of the smile
3 categories of orthodontic records
Static records (Photographs)
Dynamic records (Video)
Direct biometric measurements
In addition to the standard frontal at rest, frontal
smile and profile at rest images, Sarver and
Ackerman (AJO DO 2003) recommend 4
Frontal smile closeup
Oblique smile closeup
Dynamic recording is accomplished with digital
Digital video and computer technology enables the
clinician to record anterior tooth display during
speech and smiling at the equivalent of 30 frames
5 seconds of video for each patient may be
taken, yielding 150 frames for comparison.
One segment of video is taken in the frontal
dimension and one from the oblique view.
Direct measurement as a biometric tool
Quantification of resting and dynamic liptooth relationships is critical to smile
Direct measurement also has application in
research efforts relative to time related
changes and the repeatability of the social
Systematic measurement of resting tooth–lip
relationships virtually leads the clinician to a
quantified treatment plan.
The following frontal measurements should be
Philtrum and commissure height,
Incisor show at rest and smile,
Crown height, Gingival display,
Philtrum height is
subspinale (the base
of the nose at the
midline) to the most
inferior portion of the
upper lip on the
vermilion tip beneath
the philtral columns.
Commissure height is
measured from a line
constructed from the
alar bases through
subspinale, and then
from the commissures
perpendicular to this
Interlabial gap is the
distance in millimeters
between the upper and
lower lips when lip
absolute linear measurement of
philtrum height is not particularly
important, but its relationship to the
upper incisor and the commissures of
the mouth is significant.
In the adolescent, the philtrum height is
often shorter than the commissure
height, and the difference can be
explained in the differential in lip growth
A short philtrum in
adults results in an
lip line which makes
resemble a frown.
Incisor show at Rest and Smile
The amount of maxillary incisor show at rest
is a critical parameter esthetically, because it
is an inevitable characteristic of aging
As a general guideline, in adolescents 3-4 mm of
the maxillary incisor should be displayed at rest,
and the entire clinical crown with some gingiva
should be seen on smiling.
Generally, males show less upper incisors and
more of lower incisors, while females show more
of upper incisors and less of lower incisors.
et al (AJODO 1992) showed that the
normal display of maxillary incisors with
relaxed lips at 15 years age is 4.7 + 2 mm
for boys and 5.3 + 1.8 mm for girls. This
sexual dimorphism is evident at all ages.
Also, Whites show more of upper incisor
but less lower incisor at rest than do Asians
display is judged better at
rest than on smile, because lip elevation on
smiling is quite variable.
If exposure at rest is normal, even if a
considerable amount of gingival display
occurs on smiling, this should be considered
normal for that individual.
A gummy smile can be esthetic !
1992, Peck et al described how
orthodontists and surgeons are
conditioned to see high gingival smile
lines as undesirable and concluded that
the gingival smile line is not influenced
by upper lip length, incisor crown
height, mandibular plane angle, or
palatal plane angle.
They noted that the biological mechanisms of
the gingival smile line are influenced by
anterior vertical maxillary excess, greater
muscular capacity to raise the lip, and
supplemental factors, such as excessive
overjet and overbite.
They also noted that the location of the
gingival smile line largely depended on the
subject’s sex. On average, the smile line in
women is 1.5 mm higher than in men.
al (Int J Prosthod 1999) compared
the age changes in maxillary and
mandibular incisor display at rest and when
smiling and found that aging (from 30 years
to 60 years) was associated with a steady
decrease in maxillary incisor display and a
concomitant increase in mandibular incisor
This is associated with sagging of the
perioral soft tissue partly due to the natural
flattening, stretching and decreasing
elasticity of the skin with age.
importance of proper planning for
vertical incisal positioning in orthodontics
and orthognathic surgery cannot be
It may make all the difference between a
youthful and an elderly smile at end of
The percentage of incisor display, when
combined with crown height, helps the
clinician decide how much tooth movement is
required to improve the smile index.
Crown height is the vertical height of the
maxillary central incisors; in adults, crown
height is normally between 9 and 12 mm, with
an average of 10.6 mm in men and 9.6 mm in
The age of the patient is a factor in crown
height because of the rate of apical migration
in the adolescent.
The Smile Arc
The smile arc from the frontal view is the
relationship of the curvature of the incisal
edges of the maxillary incisors and canines to
the curvature of the lower lip in the posed
In an ideal smile arc, the curvature of the
maxillary incisal edge is parallel to the
curvature of the lower lip upon smile; the term
consonant describes this parallel relationship.
In a nonconsonant or flat smile, the maxillary
incisal curvature is flatter than the curvature
of the lower lip on smile.
et al (J Prosthet Dent 1984) in a
survey of young Los Angeles adults,
found that a great majority (85%) had a
maxillary incisal smile curve parallel to
the inner contour of the lower lip, 14%
showed a straight rather than a curved
line, and only 1% had a reverse smile
The Social Smile and the Enjoyment
The social smile is a voluntary smile a person uses
in social settings or when posing for a photograph.
When you are introduced to someone, your smile
indicates that you are friendly and “pleased to
meet” that person.
The enjoyment smile (or Duchenne smile) is an
involuntary smile and represents the emotion you
are experiencing at that moment. It is natural in
that it represents authentic emotion and dynamic
in that it bursts forward and but is not sustained.
What differenciates the social smile from the
enjoyment smile is not the activity of the
orbicularis oris musculature, but instead the
participation of the orbicularis oculi.
In the enjoyment smile there is a crinkling around
the eyes that cannot be duplicated with a social
According to both Darwin and Duchenne, we
“smile with our eyes.”
Tarantili, Halozonetis and Spyropoulos (AJODO
2005) recorded and analyzed spontaneous smiles
in fifteen children, average age of 10.5
years, using a hidden camera while they watched
a funny cartoon.
The spontaneous smile was found to develop in a
Three stages were identified:
An initial attack period from relaxed neutral
position to full smile. (500 milliseconds)
A sustaining period (Variable time period)
A fadeout or decay period back to relaxed
smiles were accompanied by display of
teeth and mouth opening, though not
On average, facial measurements showed
that the upper lip elevated by 28% and the
mouth increased in width by 27%, while the
corners of the mouth moved laterally and
superiorly at an angle of approximately 45
The smile extended over the whole face including
wrinkling around the eyes and contraction of the
orbicularis oculi muscles, confirming that the
smile was genuine.
The frequency and extent of smiling were
enhanced in the presence of other
children, showing that smiling is a social activity
that people like to share.
This study emphasizes the point that conventional
photographic records of the smile might involve
errors related to capturing a time-evolving event at
a single instant.
Video recordings may provide more
comprehensive information for assessment of
treating the smile, the social smile
generally represents a repeatable smile.
Sarver and Ackerman (AJODO 2003) chose
the social smile as the representation in
order to analyze the smile in 4 dimensions:
frontal, oblique, sagittal, and time-specific.
To visualize and quantify the frontal
smile, Ackerman and Ackerman
(1998), developed a ratio, called the smile
index, that describes the area framed by the
vermilion borders of the lips during the social
The smile index is determined by dividing the
intercommissure width by the interlabial gap
during smile. This ratio is helpful for comparing
smiles among different patients or across time in 1
This patient has small smile index value with
substantial incisor display on smile.
Frontally, we can visualize and quantify 2 major
dimensions of the smile: vertical and transverse
The vertical characteristics of the smile are
broadly categorized into 2 main features: those
pertaining to incisor display and those pertaining
to gingival display.
If, for example, the patient shows less than 75% of
the central incisor crowns at smile, tooth display is
considered inadequate. (Morley and Eubank,
Inadequate incisor display can be due to:
Vertical maxillary deficiency
Limited smile area (a large smile index),
Short clinical crown height.
Short clinical crown height could be due to
Lack of tooth eruption (treated with observation),
Gingival encroachment (treated with cosmetic
Short incisors secondary to attrition (treated with
Other vertical smile characteristics are the
relationships between the incisal edges of the
maxillary incisors and the lower lip, and between
the gingival margins of the maxillary incisors and
the upper lip.
The gingival margins of the canines should be
coincident with the upper lip and the lateral
incisors positioned slightly inferior to the adjacent
It is generally accepted that the gingival margins
should be coincident with the upper lip in the
social smile. However, this is very much a
function of age, because children show more tooth
at rest and have more gingival display on smile
than do adults.
Tjan and Miller (1984) described three types of
smiles acording to lip coverage of maxillary
incisors in full smile:
The average smile, that reveals 75-100% of the
upper incisors (most frequent).
The low smile which displays < 75% of the
maxillary incisors (found in 20% of population.)
High/ gummy smile, revealing the complete
cervicoincisal length of the upper incisors and a
contiguous band of gingiva.(10% of the
Clinical implications for Deep Overbite correction
Average and low smile types
Correction of deep anterior overbite can be made
with various combinations of incisor intrusion and
In the past, active intrusion of maxillary incisors
with intrusion arches, utility arches and other
approaches has been considered a cornerstone of
deep bite correction.
However, over-intrusion of upper incisors tends to
hide them behind the upper lip when the patient is
With increasing age of the patient and drooping of
upper lip, this would predictably worsen over time.
The optimal vertical reference position for the
maxillary incisal edge in orthodontic treatment
planning is with relaxed lips.
For young adults (20-30 years): At least 3 mm of
maxillary incisor show.
For adults 30-40 years: About 1.5 mm of
maxillary incisor show.
Adults 40-50 years: About 1mm .
In patients 50-60 years: No maxillary incisor show
Prior to treatment, each patient‟s tooth display
should be carefully analyzed at rest and speech,
before deciding whether maxillary intrusion
mechanics are indicated.
From the esthetic point of view, the best strategy
in the majority of cases of deep overbite is active
intrusion of mandibular incisors.
This is especially when the curve of Spee is
marked, and the six anterior teeth are above the
functional occlusal plane.
Achieved using overlay base arches or segmented
Reduced anterior overbite and high erupting
Use of a continuous leveling wire may overintrude the incisors into functionally and
esthetically unacceptable positions. This
should be avoided.
In such cases the first molars should be
connected with a TPA to yield reliable
posterior anchorage, and a cantilever wire
from the extra tube used to bring down the
Treatment of gummy smiles
The biologic mechanism of gummy smiles appears
to involve anterior vertical excess, increased
muscular ability to raise the upper lip on smiling,
excessive interlabial gap at rest and excess
overbite and overjet.
Different treatment strategies are needed for
patients with high smile line, involving various
combinations of orthodontic, periodontal and
Both the incisor show at rest and gingival show on
smiling should be considered.
If maxillary incisor show at rest is optimal, active
upper incisor intrusion should not be initiated.
Instead surgical crown lengthening with removal
of crestal alveolar bone should be made.
Especially desirable in case of excess marginal
gingiva and short clinical crowns.
Treatment of most severe gummy smiles
may require maxillary superior
repositioning surgery (Le Fort I osteotomy)
along with reduction of the associated
vertical maxillary excess.
Gummy smile treated with combination of
maxillary impaction surgery and crown
Gummy smiles can also be treated using plastic
surgery to correct the hyperfunction of upper lip
muscles, especially by resection of the levator
However Ellenbogen (Plastic Reconstr Surg 1984)
reported that resection of the levator labii
superioris is short-lived, with the gummy smile
returning within 6 months.
He advocated placing a spacer, either nasal
cartilage or prosthetic material, between the
stumps to prevent the muscles from being reunited
and again hyperelevating the lip.
Use of Botox for treatment of gummy smiles.
Botulinum toxin has been under clinical
investigation since the late 1970s for the
treatment of several conditions associated
with excessive muscle contraction or pain.
Botulinum toxin is produced by the anaerobic
bacterium Clostridium Botulinum.
Type A (BTX-A), marketed as Botox, is the
most potent and the most commonly used
BTX-A weakens skeletal muscles by cleaving
the synaptosome-associated protein SNAP25, thus blocking the release of acetylcholine
from the motor neuron and enabling the
repolarization of the postsynaptic terminal.
As a result, the muscular contraction is
blocked. The production of acetylcholine is
not affected by this blockade of the
Polo M (AJODO 2005) described a nonsurgical
alternative for reducing excessive gingival
display caused by muscle
hyperfunction, using Botox.
Five subjects with excessive gingival display
due to hyperfunctional upper lip elevator
muscles were treated with BTX-A injections in
the levator muscles.
This treatment modality was
effective, producing esthetically acceptable
smiles in these patients.
The improvements lasted 3 to 6 months.
Injection with BTX-A provides
effective, minimally invasive, temporary
improvement of gummy smiles for
patients with hyperfunctional upper lip
Flattening of the Smile Arc
Undesirable flattening of the smile arc is greatly
underestimated in orthodontics.
Hulsey (AJO 1970) assessed standardized
photographs of 40 subjects, 20 treated
orthodontically and 20 considered to have
normal occlusion. He noted that the curvature
of the incisal edges of the maxillary anterior
teeth was flatter in those who were treated
Ackerman et al (1998) reported that the smile arc
of as many as 32% of their patients was flattened
Normal orthodontic alignment of the maxillary
and mandibular arches may result in a loss of
the curvature of the maxillary incisors relative
to the lower lip curvature.
It is important to assess and visualize the
incisor-smile arc relationships and place
brackets so as to extrude the maxillary
incisors in flat smiles and to maintain the
smile arc where it is appropriate.
all patients routinely have their
maxillary central incisors placed 4.5 mm
above the incisal edge, their lateral
incisors at 4 mm, and their canines at 5
mm, without the clinician taking into
account the relationship of the incisal
edges to the lower lip curvature in each
individual case, the positioning may or
may not fit the esthetic criteria required.
placement, with emphasis on
the goal of attaining canine guidance
may create relative intrusion of the
maxillary incisors while extruding the
This could lead to non-consonant smile.
In patients in whom excessive gingival
display on smile is noted, and for whom one
of the treatment objectives is to reduce the
gumminess of the smile, maxillary incisor
intrusion may improve the gingival display on
However, if the smile arc relationship has not
been noted and evaluated, unwanted
flattening of the smile arc may result.
Maxillary intrusion arches or maxillary
archwires with accentuated curve could result
in a flattening of the smile arc.
When viewing dentitions, many clinicians use
the maxillary central incisors as their esthetic
However, considering the importance of the
facial midline, there remains confusion
regarding techniques for reliably locating it.
Careful photographic analysis of patients’
faces shows that prominent facial anatomy—
including the eyes, nose and chin—can be
deceptive in locating the midline.
practical approach to locating the
facial midline references two anatomical
landmarks. The first is a point between
the brows known as the nasion
The second is the base of the
philtrum, also referred to as the cupid’s
bow in the center of the upper lip.
A line drawn between these landmarks
not only locates the position of the facial
midline but also determines the
direction of the midline .
Whenever possible, the midline between the
maxillary central incisors should be
coincidental with the facial midline.
In cases in which this is not possible, the
midline between the central incisors should
be parallel to the facial midline.
If the visual junction of maxillary central
incisors is at an angle to the facial midline, it
is referred to as a canted midline.
Canting is a major design flaw in any natural
or restored dentition.
Kokich, as long as the
maxillary midline deviation is parallel to the
facial midline, even a 4mm maxillary
midline deviation was not noticed by
dentists and laypeople.
However, even a 2 mm deviation in incisor
angulation was noticeably unattractive.
transverse characteristics of the smile
in the frontal dimension are
Labiolingual crown-inclinations of teeth,
Buccal corridor and
Transverse cant of the maxillary occlusal
Arch form plays a pivotal role in the transverse
dimension of the smile. Recently, much attention
has been focused on the use of broad, square arch
forms in orthodontic treatment.
When the arch form is narrow or collapsed, the
smile may also appear narrow and therefore
present inadequate transverse smile characteristics.
An important consideration in widening a narrow
arch form, particularly in adults, is the axial
inclination of the buccal segments.
Patients whose posterior teeth are already flared
laterally are not good candidates for dental
expansion. Patients with upright premolars and
molars have more capacity for transverse
This is true in adolescents, but it is particularly
important in adults because sutural expansion is
Orthodontic expansion and widening of a
collapsed arch form can dramatically improve
the smile by decreasing the size of the buccal
corridors and improving the transverse smile
Labiolingual crown inclinations:
Generally 90% of people show the 1st or 2nd
premolar as the last tooth when smiling.
To create the illusion of smile fullness, the last
premolar should be positioned relatively upright.
Torque prescriptions for most preadjusted
appliance systems tend to create too much lingual
crown inclination, which may not be optimal from
the esthetic perspective.
Crown inclination symmetry of contralateral teeth
contribute to to an optimally esthetic
appearance., and necessary archwire correction
bends should be made to achieve this.
The transverse smile dimension is also related to
the lateral projection of the premolars and the
molars into the buccal corridors.
The buccal corridor may be defined as “ The
distance from the posterior teeth to the corners of
the lips ”(Frush and Fisher, 1958)
Frush and Fisher considered the buccal corridor to
be a normal feature of a dentition that prevents the
“Sixty tooth Smile” that is often characteristic of a
stated that the size and shape of
the buccal corridors were not important,
as long as the buccal corridors were
The wider the arch form in the premolar
area, the greater the portion of the buccal
corridor that is filled.
Only a few studies have determined the esthetic
value of the buccal corridor space.
In 1995, Johnson and Smith found that extraction
of teeth during orthodontic treatment had no effect
on the buccal corridors.
Similar findings were reported by Gianelly
(AJODO 2003) who found no differences in arch
width in extraction and nonextraction patients.
Hulsey (AJO 1970) also reported that there was no
relation between buccal corridors and smile
However, Hulsey measured the buccal corridor
from the canine to the corner of the mouth.
In adolescents, it is often desirable to increase arch
width with rapid maxillary expansion to create
space for non-extraction treatment.
expansion might fill out the transverse
dimension of the smile, but 2 undesirable
side effects could result, and careful
observation is needed to avoid these, if
1. The buccal corridor can be obliterated,
resulting in a denture-like smile.
2. When the anterior
sweep of the maxillary
arch is broadened, the
smile arc may be
This is particularly
because of the trend
toward broader arch
may not be possible to avoid
these undesirable aspects of expansion, the
clinician must make a judgment in concert
with the patient as to what tradeoffs are
acceptable in the pursuit of the ideal smile.
Moore et al (AJODO Feb
2005) the esthetic values of today may
differ from those of 50 years ago.
People now keep their teeth longer, and
there has been a shift away from complete
Thus, a full smile might no longer be
perceived as a denture smile.
same authors carried out a study in
which color slides of 10 smiling subjects
were digitally altered to produce
narrow, medium narrow, medium, medium
broad and broad smiles.
showed that lay persons
considered broader smiles to be more
attractive as compared to narrow smiles.
They concluded that having minimal buccal
corridors is a preferred esthetic feature for
both men and women, and large buccal
corridors should be included in the problem
list during diagnosis and treatment planning
In another study by Roden-Johnson et al (AJODO
March 2005), smiling photographs of 20
women treated by 2 orthodontists were
collected: 1 group had narrow tapered or
tapered arch forms, and the other had normal
to broad arch forms.Photographs of 10
untreated women served as a control sample.
The photographs with Buccal Corridor Space
were altered to eliminate the dark triangular
areas, and those without it were altered by
the addition of dark triangular areas at the
lateral aspects of the smile.
Three groups of raters
(dentists, orthodontists, and laypeople) used
a visual analogue scale to rate the
There was no significant difference in smile
scores related to BCS for all samples and for
Dentists rated broader arch forms as more
esthetic than untreated arch forms.
Orthodontists rated broader arch forms as
more esthetic than narrow tapered arch forms
and untreated arch forms.
Lay people showed no preference of arch
This study demonstrated that the presence of
BCS does not influence smile esthetics.
However, there are differences in how
dentists, orthodontists, and laypeople
Transverse cant of the maxillary occlusal
Transverse cant can be due to differential eruption
and placement of the anterior teeth or skeletal
asymmetry of the mandible resulting in a
compensatory cant of the maxilla.
Only frontal smile visualization permits the
orthodontist to visualize any tooth-related or
skeletal asymmetry transversely.
Smile asymmetry may also be due to soft tissue
considerations, such as an asymmetric smile
the asymmetric smile curtain, there is a
differential elevation of the upper lip during
smile, which gives the illusion of a
transverse cant to the maxilla.
It is poorly documented in static
photographic images and is documented
best in digital video clips.
The oblique view of the smile shows
characteristics of the smile not obtainable on the
frontal view or through any cephalometric
The palatal plane can be canted anteroposteriorly
in a number of orientations.
In the most desirable orientation, the occlusal
plane is consonant with the curvature of the lower
lip on smile.
Deviations from this orientation include a
downward cant of the posterior maxilla, upward
cant of the anterior maxilla, or variations of both.
It is important to visualize the occlusal plane and its
relationship to the lower lip.
In preparation for maxillary surgery to close an
anterior open bite, whether the posterior maxilla
should be impacted or the anterior maxilla should
come down depends on the amount of incisor show
at rest and on smile and the smile arc relationship.
This is best visualized in
the oblique view.
of the complete
smile arc afforded
by the oblique
view expands the
definition of the
smile arc to
include the molars
and the premolars
The 2 characteristics of the smile that are best
visualized in the sagittal dimension are overjet and
Excessive positive overjet is one of the dental
traits most recognizable to the lay person.
In many Class II patterns, the smile is esthetic
frontally, but the problem is obvious when
observed from the side.
In Class III patterns too, the frontal smile looks
esthetic but the oblique or sagittal view shows the
underlying skeletal pattern and dental
Incisor proclination in the
sagittal dimension can also
have a dramatic effect on
In simple terms, flared
maxillary incisors tend to
reduce incisor display, and
upright maxillary incisors
tend to increase it
Effect of retraction of incisors following
extraction of four premolars.
THE FOURTH DIMENSION: TIME
The growth, maturation, and aging of the perioral
soft tissues have a profound effect on the
appearance of both the resting and smiling
In preadolescent patients, the facial soft tissues are
still in a growth phase, and treatment decisions
pertaining to the relative facial divergence at
profile and frontal facial soft tissue topography
must take this into account.
Adolescent patients, or those at the point of
pubertal onset, have experienced the maximum
velocity in the growth of the skeletal subunits and
have roughly achieved their facial soft tissue
In adults, nuances in the aging of perioral and
facial soft tissues become increasingly important.It
is known from orthodontic cephalometric research
that, on average, profiles flatten over time.
In a direct measurement study of more than 3500
subjects, Dickens et al (World Journal of
Orthodontics, 2002) studied the changes in
philtrum height and commissure height in patients
from age 6 years to their 40s and the relationship
to the smile.
These data demonstrate the lengthening of the
philtrum and commissure, with the rate of
philtrum lengthening greater than that of the
This would explain the flattening of the “M”
characteristics of the vermilion border of the upper
lip in the youthful lip.
The effects of maturation and aging on the
soft tissues can be summarized as
Lengthening of the resting philtrum and
Decrease in turgor (or tissue “fleshiness”)
Decrease in incisor display at rest,
Decrease in incisor display during smile
Decrease in gingival display during smile.
Influence of extractions on smile
The recent criticism concerning the detrimental
effects of premolar extraction therapy on smile
esthetics has added another dimension to the 100year-old extraction vs nonextraction debate.
Presumably, extraction treatment results in
narrower dental arches which are associated with a
less esthetic smile because the dentition is less full
during a smile.
In addition, this arch width reduction creates
unaesthetic black triangles at the corners of the
mouth and „negative‟ spaces lateral to the buccal
the adverse effects of
extraction treatment on smiles is scarce.
Luppanpornlarp and Johnston (Angle
Orthod 1993) found that in comparable
groups of patients treated with and without
extractions, the post-treatment intercanine
widths of the maxillary and mandibular
arches were the same in both groups.
Johnson and Smith (AJODO‟95) determined that
smile esthetics, esthetic scores, and visible
dentition during a smile were the same in both
extraction and nonextraction patients.
Also, arch width, at least in the intercanine zone,
is not necessarily narrower after extraction
treatment when compared with nonextraction
Kim and Gianelly (Angle Orthod 2003) studied
the dental casts of 30 patients treated with
extraction and 30 patients without extraction of
four first premolars, (all randomly selected to)
determine changes in arch width as a result of
Standardized frontal photographs of the face taken
during smiling of 12 extraction- and 12
nonextraction treated subjects were evaluated by
fifty laypersons who judged the esthetics of the
increased less than one
mm in both groups, and there was no
difference between the two groups.
When arch widths of both groups were
measured from the most labial surfaces of
the teeth at a constant depth, the average
arch width of both arches was significantly
wider in the extraction sample
The mean esthetic score and the number of teeth
displayed during a smile did not differ between the
The results of this study indicate that constricted
arch widths are not a usual outcome of extraction
treatment and that neither extraction nor
nonextraction treatment has a preferential effect
on smile esthetics.
Isiksal, Hazar and Akyalcin (AJODO 2006)
compared smile esthetics among extraction and
nonextraction patients and a control group, as
judged by orthodontists, plastic surgeons, artists,
general dentists, dental professionals, and parents.
The mean esthetic scores for the extraction,
nonextraction, and control groups were 3.15,
3.12, and 3.26, on a scale of 5, respectively.
(no significant difference )
Visible dentition width relative to the smile
width ratio and intercanine distance relative to
smile width ratio were significantly different
among the groups, with extraction patients
showing a slightly wider dental arch relative
to the soft tissue.
Importance of tooth shape in smile
Many notions held today on the esthetics of
tooth shape are based on authoritative
writings aimed at guiding denture tooth
For example, Williams suggested that tooth
shape should be determined by facial form.
However, selecting tooth shape on the basis
of facial form has not been supported by the
literature. In fact,several studies have found
no correlation between facial outline and
actual or preferred tooth shape.
Other popular methods for selecting tooth
shapes in the past were based on
stereotypes: women should have round, soft,
and delicate teeth (tapering/ovoid); men
should have square, angular teeth.
Anderson et al (AJODO 2005) conducted a
study to evaluate the contributions of tooth
shape to the esthetic smile. Three groups of
judges were recruited: restorative dentists,
laypeople, and orthodontists
The judges each evaluated 18 color
photographs of smiles portrayed in either a
male or female booklet.
They were tested for incisor shape
preferences while maintaining canine
shape, and for canine shape preferences
while maintaining incisor shape.
Three shapes based on the incisal line angles
of the central and lateral incisors:
square, square-round, and round.
Three canine shapes were also compared:
pointed, round, and flat.
Restorative dentists preferred round incisors
for the female images. Orthodontists
preferred round and square-round incisors for
the female images. Laypeople did not
express a preference in female incisor shape.
All 3 groups preferred square-round incisors
for the male images.
Canine shape played a less important role
than incisor shape in the esthetics of the
Lay people tended to be less critical than
dental professionals. Restorative dentists
tended to be more critical than both laypeople
It would be wise to involve the patient in
treatment planning, whether it involves
incisal-edge recontouring or complete
restoration of the anterior dentition.
Principles of cosmetic dentistry in
Contemporary orthodontic smile
generally defined in terms of (1) vertical
placement of the anterior teeth to the upper
lip at rest and on smile (2) transverse smile
dimension (3) smile arc characteristics, and
(4) the vertical relationship of gingival
margins to each other.
Maxillary midline diastema
Sivakumar A and Valiathan A (Kerala Dental
Journal, July 2006) emphasized the need to
correctly diagnose the underlying etiology of
midline diastema, with the help of medical and
dental history and radiographic examination to
rule out a supernumerary tooth.
Such conditions can sometimes be treated with
removable appliances such as finger springs, split
labial bow, but better control can be achieved
using fixed appliances with artistic positioning
bends in the archwire.
Roots should be allowed to converge together so
that relapse could be compensated.
Especially in cases of tooth size arch length
discrepancy, it is preferred to carry out veneer
bonding to close the space.
In case of very large diastemas, a combination of
orthodontic tooth movement and veneering is
Contrary to popular belief, a study by Shashua and
Artun (Angle Orthod 1999) could find no
association between relapse and the presence of an
abnormal frenum or an osseous intermaxillary
Fremitus was the only parameter at followup
associated with space reopening.
Retention is the hardest part of treating a midline
diastema orthodontically, and invariably requires
fixed permanent retention with multistranded
stainless steel wires bonded to the lingual surface
of the incisors with composite.
Today, well occluding casts and pleasing profiles
can no longer be considered to be adequate
treatment goals for the orthodontist.
Since most people interact with each other facing
each other directly or obliquely, the smile of the
patient should be given adequate importance in
In order to correctly diagnose and treat problems
associated with the smile, meticulous clinical
observation and record taking in the form of
photos and videos is warranted, in various
sound knowledge of orthodontic
mechanics and growth changes as well as
the principles of cosmetic dentistry should
help the orthodontist to truly live up to the
epithet of “Smile Architect”.
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