Indian Dental Academy Leader in Continuing Dental Education

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


INTRODUCTION
In our modern competitive society, a pleasing
appearance often means the difference between
success and failure in both our personal and
professional lives. Scottish physiologist Charles bell
(1774-1842)was quoted as remarking that the
thought is to the word that the feeling is to the facial
expression. He pointed out in 1806 that a smile could
convey a thousand different meanings , yet it is the
most easily recognized expression. And because the
mouth is one of the focal points of the face , it should
come as no surprise that the smile plays a major role
in how we perceive ourselves, as well as in the
impressions we make on the people around us.

A charming smile can open doors and knock down
barriers that stand between you and a fuller , richer
life . An attractive or pleasing smile clearly enhances
the acceptance of the individual in the society where
he belongs and the character of the smile influences to
the great extent the attractiveness and the personality
of the individual.


Basically the smile is dependant on the musculature
and the presence of the teeth. But every person is not
fortunate enough to have a beautiful smile . The
answer to the above problem is the esthetic dentistry
which has developed leaps and bounds with the latest
technologies and materials. Prosthodontist is
probably the best person to identify the quality of
smile. Further he is also able to change the quality of
smile with the recently available innovative
techniques and the state of art restorative materials
and to plan restorations, to harmonize with the smile.


CLASSIFICATION OF SMILE (Solomon E.G.R.)
1) Depending on the nature of labial mucous
membrane
a) papilla smile
b) Gingival smile
c) Mucosa smile
2) Dependant on the lip component
a) Straight smile
b) Convex smile
c) Concave smile www.indiandentalacademy.com

Definitions:
Glossary of Prosthodontic terms. January 1999.
Esthetics
1.
Pertaining to the study of beauty and the sense
of beautiful. Descriptive of a specific creation that
results from such study; objectifies beauty and
attractiveness and elicit pleasure.
2.

Pertaining to sensation.


Esthetic reshaping
Modification of the surfaces of teeth to improve
appearance
Esthetics (adj. 1798)
1.

The branch of philosophy dealing with beauty.

In dentistry, the theory and philosophy that deal
with beauty and beautiful, esp. with respect to the
appearance of a dental restorations, as achieved
through its from and or color. Those subjective and
objective elements and principles underlying the
beauty and attractiveness of an object, design or
principle.

Dental Esthetics
The application of the principles of esthetics to
the natural or artificial teeth and restorations. (GPT
1999)
Esthetic Dentistry
can be defined as the art and science of dentistry
applied to create or enhance beauty of an individual
within functional and physiological limits.(Ratnadeep
Patil)


Cosmetic dentistry is application of the principles of
esthetics and certain illusionary principles, performed
to signify or enhance beauty of an individual to suit
the role he has to play in his day-to-day life or
otherwise. (Ratnadeep Patil)
Smile designing is a process whereby the complete
oral hard and soft tissues are studied and evaluated
and certain changes are brought about which will
have a positive influence on the overall esthetics of
the face. These changes are governed by the
principles of esthetic dentistry. Hence, a good smile
design would naturally and effortlessly blend with
the rest of the face to provide an esthetic and
functional complex

“ A well designed smile is a product of consolidated
efforts accomplished by accurate diagnosis,
methodical treatment planning, use of advanced
materials and contemporary techniques rendered by
the skilled dentist”.


Physical attributes of the elements of the
dento-facial composition
The artistic parameters to be considered for essential beauty
and those which are subtly present in natural beauty form the
fundamental principles of esthetics. Understanding these
artistic parameters of beauty and co-relaing them to the dentofacial complex will enable the dentist to appropriately scale
esthetics in any dento-facial composition.

Composition means the act of combining elements or parts to
form a whole. There are various physical attributes of the
elements of a composition that impart the esthetic value. The
various physical attributes of the elements of a composition are:

Contrast:
It is that factor which makes the various elements of a
composition visible. The eye can differentiate the parts
of an object due contrast of colors,lines, patterns,
textures, etc. The relationship between the different
parts of the face (facial), the teeth and the gums (dental)
made visible by contrast constitutes the dento-facial
composition.


Unity or oneness: “It gives different parts of the
composition the effect of a whole”. Unity can either be
static, when repeated shapes or designs are seen as in
inanimate things, like the composition of crystals; or
dynamic and changing as in living beings. Unity
between different parts of the face, and teeth is
essential to give the effect of oneness or wholeness to
the dento-facial composition (Fig.2-1b)


Cohesive and segregate forces: Any element which
tends to unify a composition is a cohesive force.
Segregative forces are those elements which break the
monotony of the composition. Naturalness has
combination of cohesive and segregative forces. A
proper mix of segregative and cohesive forces adds
variety to the composition making it more dynamic and
interesting


Symmetry: It is the regularity of arrangement of
forms either from either from left to right as in
horizontal symmetry, or from a central point to
either side like a mirror image as in radiating
symmetry. The horizontal symmetry looks
repetitive and uninteresting while the radiating
symmetry looks dynamic and interesting. In a
dento-facial composition radiating symmetry of the
teeth is more esthetically appealing and is
associated with youthfulness while horizontal
symmetry is less appealing and is associated with
aging.

Proportion: To be able to give a certain mathematical
representation of beauty for numerically expressing the
relationship of the various units that combine to make
a composition, the term proportion is used.
The relationship of the various units which are
different from each other in a composition but are
associated with each other through a certain repetitive
mathematical factor is the repeated ratio.
The proportion between the various elements of a
harmonious composition, in which the cohesive and
segregative forces are equally balanced,and whichhas
its various units in an esthetically appealing respective
proportion to each other is the golden proportion

Dominance: It exists when a strong centralized
structure is surrounded by well-demarcated,
characterized
structures.
In
a
dento-facial
composition it creates immaculate unity leading to a
harmonious composition. The absence of dominance
makes the composition weak. Color, shape and size
are the factors which can control dominance).


Balance: It is achieved when there is an exact equilibrium
between the forces present on either side of the fulcrum in
a composition. In dentistry this implies the balance of the
elements in relation to the midline. If any elements are
imbalance on one side then, to create a visual balance
either these elements are moved towards the midline or
are counter-balanced with opposite elements to regain the
balance. In balance the weight of the elements far away
from the fulcrum grows in importance


Visual tension is the tension brought about by the
presence of certain elements that cause an imbalance in
the given composition. If the presence of these factors is
closer to the fulcrum, the effect of the tension into the
fulcrum,the effective the tension induced is more
magnified as against their presence further from the
fulcrum. A distally inclined lateral incisor on one side is
compensated by a more mesial inclination of the first
premolar on the opposite side to reduce the effective
visual tension. These variations are naturally found in
dentitions explaining the reason why sometimes
irregularities in inclinations still produce pleasant
smiles.

The esthetic orientation of the dental composition
with the entire facial composition can be achieved
by taking into consideration the references, smile
elements, proportions and symmetry. These are the
factors of esthetic compositions and they help the
dentist in determining tooth display, size,
arrangement and alignment during the diagnosis
and treatment phase.


The dento-facial frame constitutes the teeth and
gingiva related to the lips and then to the entire face.
The oral frame is determined by the anatomy and
mobility of the tissues when in function surrounding
the teeth and gingiva .The exposed portion of the oral
elements i.e. teeth and gums within the oral frame
during a smile is called the smile window.
.


The anatomical elements of the face and the
biological elements that include the functional and
phonetic elements, provide the reference frames,
guidelines and points. These elements help the
dentist to achieve a general sense of orientation and
diagnosis.

References can be classified as horizontal
references, vertical references, sagital references
and phonetic references.

Horizontal references: The horizontal perspective of the face is
provided by the interpupillary line the commissural line.
The inter-pupillary line helps to evaluate the orientation of
the incisal plane, the gingival margins and the maxilla. An
imaginary horizontal line through the incisal plane and the
gingival margins should be visibly parallel to the inter-pupillary
line. This helps to diagnose any asymmetry in the tooth position or
gingival location. When an imaginary line is drawn across the
gingival margins, it may not be parallel to the inter-pupillary line
indicating a certain degree of canting of the maxilla.
Certain amount of canting of maxilla is considered normal and in
such cases mild correction of the gingival margins can achieve a
pleasing symmetry Severe canting may require an interdisciplinary approach involving surgical repositioning of the
maxilla.

Vertical references: The facial midline serves to
evaluate the location and axis of the dental midline
and the medio-lateral discrepancies in tooth
position.The inter-pupillary line and the facial midline
emphasize the ‘T’ effect in a pleasing face. The dental
midline, if perpendicular to the inter-pupillary line and
coinciding with the bridge of the nose and the
philtrum, produces an attractive orientation of the
smile.


Axial inclination is the direction of the anterior teeth in
relation to the central midline and becomes
progressively more pronounced from the central incisor
to the canine. There is a definite mesial inclination to all
the anterior teeth related to the midline. The axes of the
premolars and the first molar on either side also show
mesial inclination in relation to the midline.
The perception of tooth inclination can be viewed from
the frontal aspect around the central vertical midline,
which acts like a fulcrum around which axial inclination
of teeth on either side exhibit a phenomenon of balance
of lines Natural smiles show a deviation from these
standard axial inclination. Deviations in axial inclination
cause a visual tension when beyond the point of
equilibrium

Sagittal references: Soft tissue analysis at a
standardized position helps in studying the profile of
an individual. The contours of the upper and lower lip
support is determined by the position of the anterior
teeth and can be used as a guide for the placement of
teeth when planning restorations. The lip protrusion,
the amount of prominence of chin, recession or
prominence of the nose and its degree, all help in
profile analysis for diagnosis and treatment planing.


The E-line or esthetic line is an imaginary line
connecting the tip of the nose to the most prominent
portion of the chin on the profile, ideally the upper lip
is 1-2 mm behind and the lower lip 2-3mm behind the
E-line. Any change in the position of the E-line
indicates the abnormality in the upper or lower lip
position.
The main support of the upper lip is contributed by
the gingival two thirds of the maxillary central
incisors rather than the incisal one third According to
studies by Maritato and Douglas the lip support is a
better guide of tooth position than of incisal edge
position.

The relationship of the maxillary incisl edges to the
lower lip is a guide for the placement of the incisal
edge position and length. The pronunciation of the
‘F’ and ‘V’consonants helps determine the position
of the incisal edges. On pronouncing ‘F’ and ‘V’ the
incisal edges should make a definite contact at the
inner vermilion border of the lower lip Thus the
position of the incisal third of the maxillary central
incisor can be determind.


Phonetic references: Phonetics play a part in determining
maxillary central incisor design and position.
‘F’ and ‘V’ sounds are used to determine the tilt of the
incisal third of the maxillary central incisors and their
length. The ‘M’ sound is used to achieve relaxed rest
position and repeated at slow intervals can help evaluate
the incisal display at rest position ‘S’ or ‘Z’ sounds
determine the vertical dimension of speech.. Its
pronunciation makes the maxillary and the mandibular
anterior teeth come in near contact and determine the
anterior speaking space The amount of posterior speaking
space varies with the amount of mandibular protrusion
necessary to bring the anterior teeth in near contact for the
‘S’ sound.

Smile elements: The extent of the smile is outlined by the curvature
of the upper and lower lip and the position of the angle of the mouth,
and it determines the degree of exposure, both in the anterior and
posterior teeth, gingiva as well as the width of the buccal corridor
Smiles can be classified as passive, active (moderate) and laugh. In a
passive smile the lips are parted slightly away from the rest position
expressing content, passion, desire, surprise, etc. In an active smile
the lips move to a significant extent away from the rest position
displaying more teeth and even gums, expressing joy, welcome,
happiness, etc. Laugh is an instant fluctuation from an active smile
position where the facial muscles instantly act leading to maximum
exposure of the teeth and gums. Humorous and funny situations
usually lead to such an expression.


Lip and lip lines: The length, the curvature and the
shape of the lips significantly influence the amount of
tooth exposure during rest and in function.
A prominent tooth display is associated with a youthful
smile and most patients would like to seek the benefit of
the same. Some researchers demonstrated that the
average maxillary incisor display with the lips at rest is
1.91mm in men and 3.40 mm in Women Patient’s with
short upper lips and younger patients generally display
more maxillary tooth structure which may be up to
3.65mm.

Upper lip line helps to evaluate the length of the maxillary incisor
exposed at rest and during smile and the vertical position of the
gingival margins during smile.
The upper lip line can be classified as low, medium or high
depending upon the amount of tooth or gingival display that is
available at rest of during a moderate smile. The gingival margins
may be displayed in high lip line cases. The most apical position of
the gingiva over the facial aspect of the maxillary central incisor
and canine is slightly distal to the long axis of the tooth while in the
maxillary lateral incisor it is at the long axis of the tooth. This is
called the gingival zenith


Whenever a patient displays the gingival margins
easily on smiling or speaking, a definite pattern of
the gingival display can be recorded. This pattern
can be either esthetic or unesthetic A smile can be
termed “toothy” if more than 6mm of incisal
display is seen at rest position or “gummy” if more
than 3mm of gingival tissues are displayed in
moderate smile)


Lower lip line helps to evaluate the buccolingual position
of the incisal edge of the maxillary incisors and the
curvature of the incisal plane


Smile line: It is an imaginary line passing through the
incisal edges of the upper anterior teeth. The smile line
usually coincides or runs parallel to the inner vermilion
border of the lower lip. In a youthful smile the incisal
edges of the central incisors and canines are aligned on a
convexity and are linger than the lateral incisors, incisal
embrasures gradually deepen from central incisor to the
canine, giving the appearance of the wings of a gull. Thus
the incisal plane is said to have a gull-wing apperance
When the incisal edges of the central incisors and canines
are aligned on a convexity the incisal plane is convex.
Reduced incisal embrsures and leveling of the gull-wing
effect as in a straight smile line is associated with aging.

Negative space: Negative space is a dark space appearing
between the jaws and the mouth opening either at the
corner of the mouth of around the buccal aspect of the
posterior teeth during active smile and laugh.The lateral
negative space exists between the labial surface of
maxillary teeth and the corner of the mouth while the
buccal negative spaces appear in the buccal vestibule on
either side of the buccal aspect of posterior teeth


Obliteration of these essential spaces by dental
elements like bulky canines, wide arches or overcontoured restorations can lead to an unattractive smile.
Excessive negative space seen in cases of missing
premolars orA palatally placed posteriors and a
constricted arch also appear unesthetic.


Progressive abating in a dental composition: When similar
structures are aligned in an arch form one after the other, they
appear to progressively abate in size from the nearest to the
farthest. This gives an illusion of depth.
The essential requirement of the front to back
progression in dental composition is the alignment of the
contour of the labial and surface at the incisal third, middle
third and the gingival third of successive teeth in the arch. The
incisal mesio-buccal inclines should be well aligned to give a
smooth progression from tooth to tooth. The buccal and lateral
negative space progressively reduces the illumination on teeth
to enhance the front to back abating effect. The presence of
poorly shaped teeth, differences in axial inclinations, tooth
length discrepancies, discolorations, gingival disharmonies etc.
can lead to a visual tension resulting in a disruption of the front
to back progression.

Proportion
When mathematics is applied to the study of
ideal tooth form, a numerical relationship is established
within a single tooth form (ideal proportion) and also
between a series of teeth in the arch (relative
proportion). The position of the tooth in the arch, the
relationship between the width, the length and the face
of the tooth can also be numerically established in
relation with certain anatomic landmarks.


Gold Proportion is expressed in numerical form and
applied by classical mathematicians such as Euclid
and Pythagoras in pursuit of universal divine
harmony and balance. It has been applied to a lot of
ancient Greek and Egyptian architecture and may
be expressed as the ratio 1.618:1.
If the ratio is applied to the smile made up of
the central, lateral incisor and the mesial half of the
canine, it shows that the central incisor is 62% wider
than the lateral incisor which in turn is 62% wider
than the visible portion of the canine which is the
mesial half, when viewed from the front.

Application of sizing the central incisors from certain
facial measurements is known as the 1 to 16 theory,
whereby the height of an ideal maxillary central
incisor from the incisal edge to the gingival crest is
1/16th of the distance from the inferior border of the
chin to the inter papillary line. The same tooth width
can be measured from the mesial to distal contact
areas and is 1/16th of the distance measured from
either zygomatic prominence through an imaginary
facial midline.


Once the size for the central incisor is determined it
is essential to design its outline form. The facial
harmony method can be applied to relate the tooth
form to the facial form. Various facial shapes are
identified and descriptions such as avoid, square,
tapered and combinations of these are used The
same shape when inverted can be applied to the
central incisor design. This shape acts as guideline
for the outline forms of other maxillary teeth.


In an attempt to determine the original anterior tooth
placement on the ridge, the position of the incisive
papilla is considered as an important land mark as it
position does not alter even after bone resportion of
the anterior ridge. The distance between the posterior
border of the papilla to the outer labial surface of the
central incisor averages to about 12.5mm with a
variation of approximately 3.8mm. The end of the
first palatal ruga is located 1.5 mm to 2mmm from the
lingual surface of the canine. Many dentists have also
recorded the averages distance between the base of the
sulcus and the tip of the maxillary incisor. This
distance is measured 22mm. This helps the dentist to
determine the tooth position in the vertical plane.

Symmetry
For harmony, certain symmetries are essential while
certain asymmetries are acceptable.
Harmonious facial
features should be more symmetrical close to the facial mid
line and can be more asymmetrical away from the facial
midline.
Pleasing Smile
A naturally attractive smile that evokes a feeling of
beauty or harmony and complements the personality of the
bearer is termed as a pleasing smile.
The natural pleasing smile may not necessarily comply
with all rules of symmetry or golden proportion or may not
exhibit perfect balance without irregularity of shape.
However, the composition is esthetically appealing with unity
within its various elements.

Smile Dominance :
Different facial features stand
out differently in the eyes of every beholder. In
certain cases, the most predominantly striking
features of a face is the smile; these are the
“Dominant Smiles”.
The distinguishing characteristics observed in
people with pleasant smile dominance that can be
used as a guideline for creating the same are :
•
The maxillary central incisors exhibit a strong
presence by their size and form reflecting the
personality of the individual.
•
The maxillary lateral incisors and the canines
complement the cement incisor in terms of proper
shape and form.

•
Although numerically all proportions of the anterior
teeth do not follow the rule of golden proportion, the teeth
are so placed that they appear in suitable proportions with
each other.
•
Smile recurring ratios are observed in the teeth
from the central incisor to the premolar.
•
Well co-ordinated movements of the lips with the
other peri-oral musculature and corresponding
harmonious facial expressions, contribute to the pleasant
face during smile.
•
The complexion and texture on the face contrast
with the lip color, gingival and the teeth leading to a
distinct demarcation between the oral and the facial frame.

PERCEPTUAL ASPECTS – THE ART OF ILLUSION
Illusion is a figment of imagination where a perception
of an object is created.
Fundamental and Principles
The art of creating illusions consists of changing
perception, to cause an object to appear different from what it
actually is. Teeth can be made to appear smaller, larger,
wider, narrower, shorter, longer, younger, older, masculine or
feminine.
One being subjected to light the most fundamental
objects exhibits two dimensions, that is, length and width.
True natural light is multi-directional and on striking the
surface of the object, also reveals texture and shadows, this
adds the third life like dimension of depth.

Illusion works on two basic principles which are the
principle of illumination and the principle of light.
The most important of these is the perception that
light approaches and dark recedes. This is termed as
the ‘Principle of Illumination”. The second artistic
predilection of great importance in dentistry is the use
of horizontal and vertical lines and ridges. Horizontal
lines make the object appear wider and vertical lines
make the object appear longer. This is termed as the
“Principle of Line”.
The artistic predilection exhibited in the principle of
illumination can be maintained to change the size,
shape and the overall form of the tooth through
illusions.

Law of the face. The face of a tooth is that area on the
facial surface on both anterior and posterior teeth,
that is bound by the transitional line angles as viewed
from the facial i.e. labial or buccal aspect. These
transitional line angles mark the transition from the
facial surface to the mesial, distal, cervical and incisal
surfaces. The tooth surface slopes lingually in the
mesial and distal region while it slopes cervically from
the line angles towards the root surface. Whenever
there is no transitional line angle demarcating the
incisal portion of the facial surface, the face is bound
by the incisal edge or the occlusal tip.

Shadows created as light strikes the facial surface of
the tooth begin at the transitional line angles, these
shadows delineate the boundaries of the facial form.
Thus the apparent face is that portion of the face that
is visible to the observer from any single view. When
maxillary anterior teeth are viewed from the front only
the mesial half of the canine is visible however the
entire incisor face is visible.


The law of the face implies making dissimilar teeth appear
similar by making the apparent faces equal. The apparent face
should be manipulated, not the actual face. This is more
important in the canines and the posteriors as the ‘apparent
face’. The transitional line angles are relocated so that the
apparent faces look equal, however this results in dissimilar
areas outside the transitional line angles.
Similar faces produced attract light and appear high
lighted while the dissimilar areas that are in a shadow appear to
recede.
When the transitional line angles cannot be repositioned
on a restoration, then the portion of the tooth can be stained
darker to create an illusion that the transition line angle has
been moved.

Cosmetic contouring
Cosmetic contouring by definition is the
reshaping of natural teeth to make them esthetically
pleasing.
In natural dentitions, variations seen in tooth
shape and size some times violate the acceptable width
to length ratios as well as the golden proportion. Minor
adjustments in contours to change the perception of
these proportions increases the esthetic acceptability to
a great extent. It is indicated for giving a pleasing
appearance to fractured, chipped, extruded, malformed
or over lapped teeth

The procedure is contra indicated in hypersensitive
teeth, teeth with thin or defective enamel formation
or large pulp chambers.
The upper lip line should be used as a
reference to see how much tooth is visible when the
patient smiles. The lower lip line will help to create
a pleasing smile line. Tooth visibility with lips at
rest, when the patient talks or smiles should also be
assessed. The dentist should view the patient in
sitting and standing positions


Procedure
The procedure involves minimum tooth reduction
confined to enamel. Changes on the tooth surface of the
related tooth are carried out by working on the transitional
line angels, height of contour, incisal and facial
embrasures and adjusting incisal edge and angels.
Finishing disks are used to open incisal embrasures and
the reshaped teeth are then thoroughly polished with a fine
grit diamond paste and application of fluoride gel or foam
is recommended to minimize any chances of postoperative
sensitivity.


ESTHETIC DIAGNOSIS AND TREATMENT
PLANNING
Total Smile Analysis
Total smile analysis is a cumulative inference
analysis, drawn by interpreting and integrating
various analysis like a visual , space ,profile and
computer analysis after performing the preliminary
analysis.


Space Analysis
It helps the dentist to gauge the amount of space
available during the treatment planning stage. The
concept is to measure the widths of all the teeth and to
compare it with space present in the arch. This
determines whether the space available for restorations
and natural teeth is less or more than required.
Disproportionate spaces may be due to
discrepancies in jaw and tooth size, malformed teeth,
missing teeth, mal-aligned teeth etc. The space analysis
will provide a guideline or a frame work within which
the esthetic dentist has to plan each restoration.

Corrections of labio-lingual inclinations and rotations of the
teeth by restorative procedures will result in a change in the
width space ratio due to the change of angulation involved.
It may not be possible to match all teeth on either side of
the midline due to space or morphological constraints, but in
order to preference they should be matched as far as possible
starting from the midline and proceeding towards the canines.
Symmetry and dominance of the central incisors being an
important element of the pleasing smile should not be
compromised as far as possible.
For any changes proposed that may involve alterations
in the width of the anterior teeth, the law of golden proportion
should be closed followed. This enables the esthetic dentist to
plan any space manipulations for the restorations in terms of
illusions, actual tooth positional changes such as rotations
overlaps, spacing etc. www.indiandentalacademy.com

Profile analysis
While examining the patients profile, the normal
profile is referred to as straight orthognathic. Any
deviation from this should be recorded and considered in
treatment planning. Examination of the profile could be
in the antero-posterior plane or in the vertical plane.
If the profile is convex, the features seen include
either a normal, increased or decreased lower facial
height, a lower lip trap depending on the position of the
lower anteriors and deep mento-labial groove.


If the profile is Concave the features include either an
increase or decrease in the lower facial height. This may
also be associated with a habitual or a pseudo Angle’s
Class III relationship.
Profile analysis helps in treatment planning of the
cases that will require skeletal correction in addition to
the esthetic restorations for complete esthetic success.
This will ensure that the skeletal and non-skeletal
aspects of the treatment plan are segregated and treated
for a comprehensive, successful esthetic treatment.


Computer Analysis
Radiographs and photographic images have been
used as an essential aid in diagnosis, record keeping,
communications and treatment planning. Computer aided
technology has broadened the scope of applicatiosn as
well as enhanced the utility of radiographs and
photographs in the dental field. The new intra-oral
cameras with digital support and the radio-visiographs are
indispensable tools at the esthetic dental office. They give
enlarged images of the photographic and radiographic
outputs on the screen, without the involvement of any
hard copies of photographs or radiographs, with multiple
magnifications, and at various angles, for the dentist as
well as the patient to assess and view the intra oral
condition in a different perspective.

This becomes a handy tool for aiding correct diagnosis
as well as a brilliant motivational and communication
tool. It is also now possible to do the various facial
and profile analysis on the computer screen without
hard copies or tracings. With different soft ware
applications, the images can be altered for the patient
and dentist to appreciate the changes that Computer
Analysis


Radiographs and photographic images have been
used as an essential aid in diagnosis, record keeping,
communications and treatment planning.
Computer aided technology has broadened the
scope of applicatiosn as well as enhanced the utility
of radiographs and photographs in the dental field.
The new intra-oral cameras with digital support and
the radio-visiographs are indispensable tools at the
esthetic dental office


They give enlarged images of the photographic and
radiographic outputs on the screen, without the
involvement of any hard copies of photographs or
radiographs, with multiple magnifications, and at
various angles, for the dentist as well as the patient
to assess and view the intra oral condition in a
different perspective. the proposed treatment
modalities may bring about without actually
carrying out the treatment.


In a particular case, esthetic enhancement with a
change of arrangement, form, shape or color can be
demonstrated quickly. Thus computer analysis can
be used as a quick reference which can guide the
future artistic creations that the dentist may consider,
However, the occlusal parameters cannot be
addressed without appropriate devices and hence the
actual three dimensional aspect of the change cannot
be applied without error. Promising the patient
results close to what are seen through a computer
analysis could lead to dis-satistication and hence the
dentist should consider other diagnostic means before
designing definitive treatment plans.

ROLE OF TECHNOLOGY IN CHANGING SMILE
New technology helps us to preview the end
results.The following high tech tools can be
incorporated:
1) Extra oral video camera: It allows to have a
detailed record of the patient's face while moving and
talking- a much more helpful tool than a still
photograph. It can record the patient in various
moods and gestures and give us the minute details the
patient may be unaware of. This can be shown to the
patient with the help of computer imaging . Different
smiles and profiles can be applied to the patient's face
and the patient can be given the opportunity to choose
the best smile designwww.indiandentalacademy.com

2) Intraoral video camera: It is an easy to use unit
designed with reliability, performance and image
quality. Intra oral examination from every angle
with the smallest details can be viewed as close as
2mm. fron the tooth. With it we can explain certain
conditions and treatment options much more
accurately than with sketches, mirrors and X- rays.
Introral cameras can be integrated with a
computer imaging system to capture the detailed
images of the patient's oral cavity. These images can
be modified according to the proposed treatment
options and shown to the patient. At the click of the
mouse a particular tooth can be elongated or
widened , the effect of which can be shown to the
patient for his approval.

3) Computer or voice activated data
Using voice activated technology , we can
document our findings by speaking into the
microphone that are connected to a computer
which has been "trained" to recognise a limited
vocabulary. The computer than stores the
infomation and even graphics( related to smile ) so
that various procedures can be discussed with the
patient.


4) T- Scan and Digital Radiography
By using this scan , buccolingual width of the
jaws as well as the location of anatomic features such
as the mandibular canal and the maxillary sinus can
be determined which is useful while placing an
implant in the esthetic position.
Now-a-days manufacturers promote digital
radiography system and video camera in one unit i.e.
single hand piece which will be concenient for use.


5) CAD/CAM
With CAD/CAM ( Computer assisted design/
Conputer assisted manufacture) technology we can
design veneers and crowns to enhance smile while the
patient waits. The so called "mock- up" of a planned
cosmetic teatment also has been shown to be quite
useful. It also allows clinician to visualise the desired
results and solve potential problems before providing
treatment to the patient.


6) Lasers
The dental lasre uses a beam of light in place of
scalpel to perform delicate gum surgery and crown
lengthening/ gingivectomy and gingivoplasty.
The advantages of this procedure are1) Controlled bleeding which provides dry
operating field and hence excellent visibility.
2) Reduced operating time and reduced post
operative swelling, pain and scarring.


7) Computer Imaging
It improves communication between the
patient and the dentist by allowing both to
visualize , evaluate and agree on treatment. It
allows to " see" various looks before deciding
upon treatment.


8) Computer Controlled Injection Technique
The P- ASA (Paltal approach anterior superior
alveolar ) is a new block injection technique that
provides anaesthesia of the maxillary anterior teeth
from a single injection without numbness of the face ,
lips and the muscles of facial expression. The injection
can be administered in a comfortable and consistent
manner, using a computer controlled local anaesthetic
delivery system( the wand). This technique prevents
distortion of the smile line and enhances restorative
procedures that use the lipline as an esthetic reference
element.

9) Abrasive Technology
In this technique , a jet air stream with micro
abrasive particles is used to remove the stained areas.
It is painless, faster and does not require the use of
anesthesia. It can be used in any quadrant for any
depth of decay without damaging the healthy tooth
structure. After the removal of the stained areas , the
tooth structure can be built up with composite.
It is also useful during repairs to existing
composite or porcelain restorations because it
roughens these surfaces allowing the reparative
materials to bond them more rapidly .

Occlusal considerations
The esthetic dentist has a major challenge in
dealing with restorative situations in the mouth where
occlusal considerations are critical. Natural and
restored maxillary and mandibular teeth should have
optimal functional contact relationship resulting in the
even distribution of load in static and dynamic
positions leading to minimal trauma of the teeth and
supporting structures. This requires a thorough
understanding of the stomatognathic system which
comprises of the temporomandibular joint, the
ligaments, related musculature and the dentition and
their coordinated three dimensional movements.

Concept of occlusion
A thorough knowledge of the various concepts
of articulation accompanied with application of the
same is mandatory for successful restorative
rehabilitation.
The various concepts of occlusion are
Bilateral balanced occlusion
• Group function or unilateral balanced occlusion
Mutually protected occlusion

In large or complex rehabilitation’s with fixed prosthesis,
a sequential and correct method of recording the jaw
relations should be followed since any error would be
magnified in the final outcome. This would be
detrimental to the survival of the surrounding tissues and
the restoration. The hinge axis of the mandible should
recorded with a kinematic face bow and transferred to an
adjustable. Arbitrary hinge axis face bow is useful for
routine work and gives a fairly accurate relationship
(error of 5mm).
Correct centric relationship and
protrusive and lateral inter occlusal records are made in
rigid materials and the articulators are adjusted
accordingly. Correct incisal guidance is computed and
adjusted. This logical and systematic approach ensures
minimum error.

Forces on the dentition
On the dentition it is influenced by several factors
like position of the teeth in the arch, masticatory
dynamics, relationship with the opposing arch, crownroot ratio, direction, duration, frequency and character of
the forces during functional mandibular movements and
parafunctional habits.
The peri-oral musculature and the tongue exert a constant
force on the teeth. These forces are lighter and in a
horizontal direction. Swallowing also exerts forces on a
continuous basis throughout the day.

The peri-oral musculature and the tongue exert a
constant force on the teeth. These forces are lighter and
in a horizontal direction. Swallowing also exerts forces
on a continuous basis throughout the day. The heavier
natural forces exerted on the teeth are during
mastication and are primarily directed perpendicular to
the occlusal plane in the posterior region. They are
exerted infrequently and for a short duration during the
day.


In mutually protected occlusion, where there are no
posterior contacts in eccentric movements, fewer fibers of
the temporalis and masseter muscles and stimulated
resulting in reduction of the forces applied on anterior
teeth by two thirds.
Research on implant prosthesis and crowns with
cast cores on maxillary incisors have shown permissible
angle of up to 25° between the crown and root for
maintenance of adequate periodontal health.


Parafunctional movements
Are identified as a cause
for occlusal wear and excessive forces. Parafunction can
be related to local factors like malocclusion or to
systematic factors like cerebral palsy, epilepsy and can
also be stress or occupation related. Bruxism, clenching
and parafunctional tongue thrust are the important
parafunctions which the dentist should consider in the
treatment planning stage.
Bruxism
Rehabilitation of these cases not only
involves elimination of the causative factors but
establishment of correct anterior incisal guidance to
eliminate all posterior contacts during mandibular
excursions.

Clenching : Is the force exerted from one occlusal
surface to other without movement. These forces are
directed more vertically to the plane of occlusion in the
posterior region of the mouth. Fremitus is often found
in the clenching patient. This is vibratory type of a
force felt with a finger kept in contact with the facial
aspect of a tooth while the patients taps the teeth
together. It is noticed clinically on many cervically
eroded teeth, and if the occlusion is carefully
evaluated, it shows signs of excessive forces. This
cervical defect is called cervical abfraction. During the
management of these cervical defects occlusal
adjustments need to be considered along with adhesive
restorative methods for a long term success.

Parafunctional tongue thrust : Is an unnatural tongue
force which can exert an abnormal horizontal force on the
anterior teeth.
Esthetic treatment planning and sequencing
Treatment sequencing is an integral part of
treatment planning. It is a phase wise distribution of
treatment procedures which will be programmed or
charted considering periods of healing, patient
convenience, inter disciplinary treatment modalities and
is the fundamental feature of a meticulous treatment
execution

Although some basic periodontal, pulpal and
temporomandibular problems would be addressed at the
initial therapy stage, more definitive periodontal or pulpal
treatment may be necessary during the definitive therapy
stage. Certain cases involving endodontic posts or
implants etc in the esthetic zone may pose a challenge to
the dentist in term of giving suitable interim restorations
that will not interfere with the healing process.


Mock up
Mock ups are made for diagnostic reasons
during the treatment planning phase as well as for
reference purposes during the treatment phase. For
the cases requiring major esthetic correction
involving many anterior teeth the dentist can work
on the space availability and allotment for every
tooth on the mock up even before proceeding for the
tooth preparations.
A cosmetic preview with the help of composite resins
is the easiest and fastest procedure to help the dentist
in diagnosis, treatment planning as well as creating
references during treatment execution

Composites can be put on the facial tooth surfaces
including spaces or even the gingiva to determine the
change of position of teeth desired at the final
restorative phase. The dentist can show this preview
of the patient and get his opinion regarding tooth
position, shade, shape etc.
The occlusion usually will restrict the
restorative ease in many cases. The lower incisors
should be thoroughly examined and the contacts of
the palatal aspect of the upper teeth marked . The
functional movements in the mouth can also be
checked at this time to determine any potential
occlusal

Obstructions or difficulties that may arise at the time
of treatment. Some adjustment in the incisal edges of
the mandibular incisors might be mandatory before
proceeding with esthetic correction for the maxillary
anteriors.
In cases requiring reduction of tooth structure
like in overlapping teeth, a diagnostic wax-up would
be more beneficial as the required reduction of the
teeth can be done on the study casts and suitable
colored wax-up can be used to visualize the end result
and preparation design


In cases requiring closure of spaces and where crown
lengthening could be required to improve the width to
length ratio of the final restorations, a composite
preview could be easily used. Before crown lengthening
procedures the extent of gingivectomy and the exact
contour to be established on the facial aspect contour to
be established on the facial aspect is determined by the
location of the gingival zenith after the placement of
the final restoration. Hence a composite preview is
used to determine the gingival contour and the
gingivectomy is performed according to this reference.
Once crown lengthening is achieved and after sufficient
healing period elapses, composite or ceramic veneer is
placed to give the final desired result.

COLOR
Dimensions of color
Color cannot be perceived without light,
which is a form of electoro-magnetic energy visible
to the human eye. The visible spectrum of light lies
in a narrow band of 380nm to 760nm. It has the
ability to stimulate the cells in the retina which is
interpreted by the brain, discerning the sense of
color.


Clark stated that “Color, like form, has three
dimensions”. Hue, which is the name of the radiant
energy, Chroma, which is the saturation of the hue
and value, which is the relative lightness or darkness
of the color. Since clinical color matching depends
upon the ability of the dentist to perceive the
difference in the tooth shade guide comparison;
complete understanding of the color dimensions in
critical.
The Munsell color order system best serves
the needs of the dental profession in its tempt to
visualize and organize color.

Hue : In Munsell’s words, “It is that quality by which
wwe distinguish one color family from anther”.
Generally there are six hue families. Violet, blue,
green, yellow, orange and red. For example, in the Vita
shade guide there are four hues A, B, C and denoting
reddish brown, reddish yellow, grayish and reddish
grey respectively.
Chroma :In Munsell’s words, “it is the quality by
which we distinguish a strong color from a weak one.
“Human teeth fall into the yellow to yellow red area of
the Munsell color order system. Pale colors have a low
chroma whereas intense colors have high chroma.

Value : Value or brilliance is the relative blackness or
whiteness of color. On a scale of black to white, white
has “high value”, black a “Low value” and Midway
between black and white is the medium grey. Value is
the only dimension of color that can exist by itself.
Opacity and Translucency: As light strikes a
surface, it is either totally reflected, totally absorbed or
a combination of both. Opaque objects reflect all or
most of the light that is incident on them whereas
transparent objects transmit all of the light that is
incident on them.
When part of the light incident on an object is
transmitted, while the rest is scattered, the property of
the object is known www.indiandentalacademy.com It decreases with
as translucency.

Translucency, in effect, is the three dimensional spatial
relationship or representation of value.
Highly
translucent teeth tend to be lower in value, since they
allow light to transmit through the teeth, while opaque
teeth have higher value.
There might be inter tooth as well as intra tooth
differences in the translucency. Its extend can vary
according to the age of the patient due to the
degenerative and reparative changes in the enamel and
dentin. To mimic natural teeth the effective use of
restorative materials should largely depend upon this
translucent effect.

Mechanism
The change in color perception of two objects
under different light sources is called metamerism.
For example , a shade guide tooth matches the natural
tooth under incandescent light but not under
fluorescent light. This can be attributed to the
difference in the radiant energy of two different
wavelengths of light.
The standardization of lighting condition during
hade matching diminishes the effect of metamerism.


Fluorescence
The emission of light by an object at a different
wavelength from that of the incident light is called
fluorescence. The emission stops immediately on
removal of incident light. Teeth fluoresce with a
stimulus in the range of 340nm to 410nm. This
spectrum is in the blue range. Thus, according to the
principles of additive color, the emitted blue light acts
with the yellowness of the tooth to produce a whiter
tooth. Fluorescing pigments incorporated in the
ceramic restorations by the ceramist and in the
composite restorations by the manufactures may thus
be advantageously used in altering the perception of
the final result.

Gloss
Gloss is an optical property associated with a
smooth surface that produces lustrous surface
appearance and thus reduces the effect of color
differences. Increase the brilliance (value0 of the final
result.) In dentistry, unlike spectral colors, the
restorative materials have pigment colors incorporated
in them. Predictable restorative color outcome can
only be achieved by proper understanding of primary,
secondary and complementary factors.


Primary color
Are those colors that cannot be formed by mixing of
multiple colors. They occur naturally by themselves.
For example, red, yellow, blue etc.
Complementary colors
According to the additive principle of colors,
complementary colors can be used to lower the value
of the restoration and not to complementary color
may be added to the respective hue to decrease the
value.


Perception of color.
The perception of color involves many
physiological , physiological and physiological aspects
The light source.
The light source has the color of the emitted light
and is described in color temperature (Kelvin.). The
lighting environment makes a significant differences in
the perception of color. The teeth and the shade guide
should be sufficiently illuminated. The light reflected
from a glossy surface obscures the viewer’s perception
of light. Shadows should be eliminated as they reduce
the available light and hide details.

The dental operator maybe illuminated by
combination of natural sunlight and artificial light,
The artificial light may be incandescent
(predominantly) blue. Also the ratio between the task
light (which falls directly on the working area) and
the ambient light (derived from the surroundings),
known as the contrast ratio, should be higher than
3:1, but lower than 10:1. This can be attained by
regularly measuring the intensity of light, cleaning
the diffusers and the light sources any by replacing
them when their effective life is over.


The observer
The stimulus of light travels through cornea,
lens, aqueous and vitreous humors and reaches the
cones and rods of the eye. The cones function for day
light vision and color perception whereas rods are
sensitive to the quantity of light perceived. These
stimuli are then sent to the brain, where they are
computed and interpreted as color. This complexity
of color is further modified by the embryonic
development of the brain, aging process, aberrations
of color vision like color blindness, dichromatism,
mental fatigue and drug intake.

The object
The quality of the color of an object (the tooth)
depends on its ability to absorb, reflect, transmit or
refract the light energy falling on it. The surrounding
environment greatly influences the color. The ceiling
and the walls reflect light and should not be pained in
bright colors. Neutral colors like grey or white should
be selected.
Contrast effects
The background considerably affects the
perception of color. Different contrasts effects that
alter the color vision, should be understood.

Simultaneous contrast
Is visualized when two objects are viewed at the
same time. The light or dark contrast can be
correlated to the surrounding environment like skin
tone, hair color and brightness of adjacent soft tissues
and teeth. Hence, brighter shades should be chosen
for light toned patients and darker shades for pigment
toned patients.
Actual contrast
Is influenced by the size and the chroma of the
tooth. A brighter tooth looks larger while a darker
tooth of the same dimension look smaller.

Shade selection
Shade selection is a complex procedure due to
the variations and differences in the optical
properties of the new generation of cosmetic
restoration materials. It can be well accomplished by
understanding the fundamentals of color and
adopting a proper methodology of matching shades.
The effective communication with the laboratory and
precise fabrication and meticulous finishing of the
restoration will affect the color of the final
restoration.


Shade selection sequence
Any color modification procedures like
bleaching or microabrasion should precede color
selection after ensuring color stabilization.
•
Make the shade selection at the beginning of the
procedure as well as over different appointments
(diagnosis, prophylaxis etc.)and cross check these
observations.
•
View the patients at eye-level. The operator
should stand between the light source and the patient.
•
In a contrasting environment, colors look more
intense and brighter. Hence it is wise to ask the
patient’s to remove artificial lip color.

•
Place the tabs as close as possible to the area
that is being checked.
•
Moisten the tab and eliminate the worst
match.
•
Evaluate the value (upper to lower). Value is
the most important factor in shade matching. If the
value blends, small variation in hue and chroma will
not be noticeable. The value is to be matched with
eyes half closed.
•

After value, mark the translucency

•
Match the chroma (more or less saturated)
and finally, hue in that order.

•
To avoid hue sensitivity, rapid observation is
made for 5 seconds (not more than 20 seconds). Look
away, ideally stare at a blue surface, which will
readapt the vision to the orange yellow portion of the
spectrum.
•
Match prior to tooth preparation, since
preparation dehydrates and changes color due to the
debris of preparation.
•

Match the tab with the opposing tooth also.

Metamerism complicates color matching, as the tabs
look different under different light sources. The best
approach is to use three light sources; cool white
fluorescent light, incandescent operatory lamp and day

•
When in doubt, always select higher value and
lower chroma, since it is easy to lower value and
increase chroma
•
Shade tabs of different batches don’t always
match, hence it is wise to sent the actual selected
shade tab to the technician.
•
Make a decision regarding relative translucency,
area of hypo calcification, increase saturation, crack
lines surface texture and other characterization.
Make a drawing of the facial surface and record all
patient information graphically.

Dental Bleaching
Bleaching is one of the most commonly sought
elective dental procedures to brighten a smile. It is a
simple, fast and effective treatment to change darker
tooth shades into lighter ones.
Chemistry of bleaching
Bleaching process is based on the oxidation of
bleaching agent. Oxidation is the chemical process by
which organic materials are converted into carbon
dioxide and water. The oxidation reduction reaction
that takes place in the bleaching process is called the
redox reaction.

Bleaching slowly transforms the organic
substance in the stained tooth into chemical
intermediates that are lighter in color than the
original tooth shade. In a redox reaction the
perioxide (oxidizing agent) has free radicals with
unpaired electrons, which it gives up, becoming
reduced. The stained tooth structures accepts
these electrons and becomes and oxidized, thereby
reducing the organic colorants. The free radicals
produced by the peroxides are perhydroxyl and
nascent oxygen. Of these, the perhydroxyl is a
more potent free radical which is responsible for a
better bleaching action.

In order to promote the formation of perhydroxyl
radicals, the peroxide is buffered to a pH range of 9.5 to
10.8. The buffering provides a greater amount of
perhydroxl radicals, which results in a better bleaching
effect.
The most common bleaching materials used are
hydrogen and carbamide peroxide. Carbamide peroxide
first breaks down into hydrogen peroxide which then
further liberates the above mentioned free radicals.
Unlike the hydrogen peroxide, the carbamide peroxide
bleaching agent must remain in contact with the teeth
for a longer period of time to obtain complete efficiency
of the reaction. Carbamide peroixde is less irritating to
the gingival tissues thus better tolerated by the patients
when used as a home bleaching agent.

Mechanism of bleaching
In the presence of moisture as well as surface
debris on the tooth, the ionization by hydrogen
peroxide occurs by decomposition into water and
nascent oxygen which is a weak radical making the
peroxide which is a weak radical making the peroxide
inefficient as a bleaching agent.
Hence, it is
important to have teeth dry and free of surface.
Increase in the temperature, higher peroxide
concentration and the duration of exposure of the
tooth structure to the peroxide within limits, direct
affects the oxidation process leading to a greater
degree of color change.

Saturation Point
Prolonged used of a bleaching agent causes
the whitening action to slowdown beyond a point
during the treatment. This is the saturation point.
The bleaching if allowed to continue, begins to
break the inorganic structure from the enamel
becomes rapid. Bleaching should thus be stopped at
or before the saturation point.
If bleaching is done beyond the saturation
point, it clinically manifests an increase in porosity
on the tooth surface. A fluoride application is
recommended and no bleaching agents should be
applied allowing the enamel to remineralise.

Procedure for bleaching
Use of concentrated heroine or carbamide peroxide
solution available in standard 35% concentrations.
In a technique described as ‘assisted office
technique’, 35% carbamide peroxide is tray loaded
for 45 minutes, after following required protocols.
Some bleaching materials are available in a
combination of a hydrogen peroxide and carbamide
peroxide in 20% and 16% concentrations
respectively. There are other “dual cure” systems,
which initiate the bleaching reaction on the tooth
surface through a chemical reaction which is
catalyzed through light activation by a visible blue
light spectrum.

Preparation of trays
The bleaching procedure is recommended for
the number of teeth seen in the patients active
smile. 1 millimeter reservoir for the bleaching gel.
On the modified cast soft and clear vacuuform
matrix of 0.035”thickness is made. The matrix,
carefully trimmed to cover only the clinical crowns.
Contract the bleaching gel with marginal gingiva
may result in tissue irritation hence vacuuform
trays should have a marginal seal to eliminate
contact of the caustic bleaching gel with the gingiva.


Isolation of teeth
Proper isolation of area with cotton rolls or rubber
dam is mandatory. The gingival surface is wiped and
dried sufficiently.
Etching of tooth surface
Each tooth is etched on labial surface for 10 to 20
seconds using 32% - 37% orthophosphoric acid. This step
removes any superficial surface stains and enhances the
penetration of the bleaching solution into the tooth surface
producing a greater stain reduction. Excessive etching
causes the demineralization of the enamel matrix, leading
to surface irregularities and causing sensitivity.

Application of bleaching material
The bleaching materials is slowly loaded in to
the vacuufrom trays so that it spreads all over the
labial surface of the teeth to be bleached. The trays
are kept in place for an average duration of 30
minutes depending on the type of material used
and the manufactures recommendations.
Micro-finishing and polishing
Following bleaching, the teeth are microfinished using fine abrasive disks. Final polishing
is done with aluminum oxide or fine grit diamond
polishing pastes.

Office bleaching of non vital teeth
The two most commonly used agents for bleaching of
non-vital teeth are hydrogen peroxide and sodium
perborate.
Home bleaching
Bleaching may be carried out at home by the patient.
The home bleach technique involves the application of
bleaching agent through the use of vacuuform trays. The
frequently used bleaching agent is 10% - 15% carbamide
peroxide.


Bleaching in relation to bonded restorations
It was determined in clinical studies that the
bond strength of composite to enamel is reduced
when the tooth is bleached. The primary cause for
the reduced bond strength is the presence of the
residual peroxide or oxygen, which interferes with
the polymerization of resin bonding systems and
restorative materials. Any bonded restorations in
the bleached teeth need to be done after a period of
two weeks. If bonding cannot be delayed by two
weeks then the enamel should be roughened and
acetone based adhesive system used.

Enamel microabrasion
Hydrochloric acid *18%) pumice
abrasion can remove white enamel opacifiers,
multicolored defects and many brown, orange,
yellow enamel spots and streaks, regardless of
etiology. These stains can be eliminated with
insignificant enamel loss if the stain is limited
to a thin layer of tooth surface (approx.
0.5mm).
This procedure can be used
independently or prior to bleaching to give
optimal results.

Management of Fluorosis stained teeth
A solution of anaesthetic either, hydrochloric
acid and hydrogen peroxide may also be used for
bleaching teeth with fluorosis stains. The anaesthetic
either removes surfaces debris, the hydrochloric acid
etches enamel and hydrogen peroxide bleaches it.


Esthetics with composites
Considerations in preparation design for anterior
teeth.
The preparation design for anterior composite
restorations should encompass elimination of decay,
function and longevity, and esthetic predictability.

Function and longevity
A pre-operative analysis of the occlusion is
crucial to determine the palatal extensions and the
acceptable length in upper anterior restorations.

. Checking the lateral and protrusive excursions
will given an ideas as to how far palatally the final
restoration can be placed. Researchers have found
that a minimum of 1.5mm – 2mm of the composite
thickness is essential to give sufficient strength to
the material. A conscious effort has to be made to
leave at least 2 mm of composite thickness at the
margins for good marginal adaptation and retention
in larger restorations.


Esthetic predictability
After elimiantion of the decay and determining
the extent of preparation required for function and
longevity , the preparations are evaluated and if
required redefined.
The preparation design is
extended to allow a smooth transition of shade from
the composite restoration to the rest of the tooth.
This enables the restorations to achieve esthetic
excellence.
To create proper tooth from, shape, shade and
texture, and to optimize function, all cavity
preparations designs should have extension for
function and esthetics (EFE).

The EFE ensures that the margin of the restoration
overlays the defects. The esthetic advantages are :
•

Successful masking of the defect

•

Better marginal adaptation

•
Natural transition of shade between composite
and tooth
•

Ease of finishing and texturing


EFE and placement of composite for malaligned
teeth
The preparation in malaligned teeth is a typical
and depends upon the degree of rotation and
angulation exhibited by the teeth and hence a
uniform layer of composite cannot be placed to treat
such teeth. The effective use of opaque composites in
areas having no tooth or thin palatal structure,
improves the blending of the restoration. Creating
surface characteristics and effectively placing the
transitional angles on the facial surface can help to
over come deficiency in tooth reduction.

EFE and placement of composite for closing spaces
Diastemata may be manifested to due to
microdontia, discrepancy between tooth size and the
available ridge and also due to variation in the tooth
morphology. Although some natural spaces may be
esthetically and phonetically acceptable, others are
not and need corrective restorative procedures.
However, in cases where the size of the teeth is
normal and a diastema still exists, restorative
creations using principles of illusion is recommended.


When a diastema is small up to 2mm, no tooth
preparations is required. The minimal thickness of
composite can be adequately shaped especially at the
cervical region to allow good maintenance. However,
in cases of a moderate diastema between 2-4mm the
EFE should be given on the proximal curvature of the
labial surface of the tooth. The extension preparation
is close to the gingival margin and follows the contour
of the inter dental papilla to end on the palatoproximal line angle. The preparation is in the form of
a depression, which provides a definite stop and is
done with a chamfer bur.


The preparation design ensures adaptation of sufficient
bulk of the composite at the gingival margin creating
contours favorable for gingival health.
The labial
extension allows smooth blending at the composite tooth
interface while the palatal extension provides stability and
retention. In cases with diastemata larger than 4mm a
similar preparation coupled with recontouring of the other
proximal surface of the tooth to maintain tooth
proportions and form may be required.
Diastemata are filed in one tooth at a time. A
celluloid matrix is effectively used to get the desired
contour

EFE and placement of composites in cervical defects
Cervical defects are caused due to caries,
abrasion, erosion or abfraction and a combination
thereof.
Although management of these defects
involves similar procedures, their proximity to the
gingiva makes it difficult to restore. Before any
preparation, a gingival cord is placed in the sulcus to
allow a proper access to the defect and to keep away
sulcular fluid or blood from the cavity margins. Since
bond strengths with the cementum are weak, no
additional bevel is recommended at the cervical region
in cases where the base is in the cementum.

A round bur is used to roughen the surface of the
cavity and a long bevel is placed on the occlusal edge
of the cavity. After etching, the cord ischanged and
bonding adhesive is applied followed by flowable
composite which is used as an intermediate layer.
The gingival cord is removed after completion of the
filling to facilitate finishing and polishing. The
occlusion is adjusted, especially eccentric contracts,
to take care of primary or secondary abfractions.
Fine diamonds or carbides are used to finish the
margins.


Tissue management
Success of composite restorations depends not
only on preparation design, bonding procedures,
quality of restorative material and skill of the dentist
but it also largely dependent on the thoroughness of
the isolation. The greatest challenge involved in
creating predictable composite restorations near the
gingival margins is to achieve hemostasis and control
of sulcular fluid. Therefore, tissue management
becomes an integral element of these procedures.


In case of contamination of composite by blood, blood
pigments containing iron or ferric sulphate migrate
between the composite and tooth surface or between
different layers of composite. These pigments turn
dark and are visible as a black-brown discoloration in
the restorations. Salivary contamination as well as
crevicular fluid ingress in the preparation can cause
bonding failures at these areas leading to the failure of
the restoration.


Retraction cords displace the gingiva and keep blood
and suclurlar fluid away allowing proper access with
contamination during placement and finishing of
composites. In cases where the cavity design is close to
the gingival margin, double retraction technique can be
effectively used. Astringent impregnated cords should
be used with caution as nay residual astringent can
potentially contaminate the tooth surface to be bonded
causing a bonding failure.


Shade matching
Shade selection is done following standard
protocol with references to the incisal third, middle
third and the cervical third of the tooth. The
uniqueness of composites permits pilot shade test to
reconfirm shade attributes before final restorations.
The pilot shade test is carried out using a selected
shade in a bulk of 1.5mm- 2mmon the involved tooth
and a contra lateral or guide tooth. The composite is
then cured and finished and the accuracy of the shade
match is confirmed. Any changes in the value,
transluency and chroma is recorded and the shade is
changed if required.

Three procedural steps for finishing and polishing
•
Gross reduction, contouring , defining the
margins. Fine grit diamond abrasive or tungsten
carbide finishing bur can be used for the these
purposes (100µm size abrasives)
•
Intermediate finishing is used to reduce
scratches left by gross reduction and to blend all
surfaces with each another keeping the orientation of
various facial planes intact (less than 100µm but
morethan 15-20 µm particle size).
•
Final abrasive polishing imparts enamel like
effect on the restorations. Loose abrasive devices,
disks, pastes with particle size less than 20µm is used.

Esthetics with Ceramics
Ceramics laminate veneers
In 1930 Charles Pincus used a unique
procedure to improve the smiles of certain Holly
wood actors. This technique was non-invasive and
gave good esthetic results with resin and air fired
ceramics. But the veneer coping made then lacked
permanent retention and later this technique was
discontinued.


Considerations in tooth preparations for ceramic
laminates
Tooth preparation design will depend upon the
existing color of the teeth, whether change in
alignment or an increase in height of the final
restoration is sought.
When a mild to moderate
discoloration has to be masked the preparation can be
minimal from 0.3mm cervicaly to 0.5mm at the incisal
edge. Whenever a severe discoloration has to be
masked the preparation has to be deeper to allow
more die spacer to be applied on the model. His
excessive space allows use of resin curing cement to
mask the severe discoloration. Adding more opaque
ceramic in the veneer will mask undesirable tooth
color but will limit www.indiandentalacademy.com
the display of vitality.

A more translucent ceramic will allow more light
transmission and reflection internally making the
restoration more vital. If change in alignment is
indicated then more preparation will be required in
certain areas. When length of the veneer has to be
increased a palatal extension is recommended.


Preparation of maxillary teeth for ceramic laminates
•
Mock preparation on the pre-operative casts
and diagnostic wax up gives valuable information
about he amount of tooth preparation and helps to
visualize the end result.
•
Local anesthesia may be required when the
preparations reaches the dentin and to facilitate easy
gingival retraction procedures.


•
Self-limiting three-tiered depth cutting burs of
known dimensions (0.3mm and 0.5mm) facilitate
repaid, adequate and conservative tooth reduction.
The depth roves are made by moving them on the
facial surface from the mesial to the distal and by
changing the angle of the bur to facilitate their
orientation in two planes (Fig. 8-1a). Then the facial
reduction is achieved following the labial contour of
the tooth till the depth grooves. Besides, the contralateral tooth can be used as a reference to check
adequate tooth preparation. Selective labial tooth
preparation is required to create a favorable arch
form.

•
A modified chamfer margin is preferred to
allow distinguishable finish line in the impression,
definite seat and adequate bulk for laminates. The
margin is usually supra-gingival or equip-gingival.
The margin is taken intra-crevicularly in certain
cases to mask the underlying discolored tooth and
cover cervical lesions.
•
The proximal finish line is placed into the
embrasure area to ensure that the margin between
the laminate and the unprepared tooth structure is
well hidden. Deficient preparation reveals unaesthetic
margins proximally.

•
Incisal preparation depends on whether an
increase in tooth height is required or not. In case
where the increase in not sought, the incisal
preparation ends midway between the labio-lingual
width of the incisal edge. A facio-incisal angle of 30 o
with a definite stop (window preparation)is given.
Butt joints are rarely recommended .
In case when the length of incisor is to be increased,
the incisal table is flattened with a bevel of 45 o
palatally. The palatal preparation is a wrap-around
design with the margin placed inferior or superior
but never at the contact of the mandibular incisor in
centric occlusion

•
Similarly, window preparations are advocated
for canines and premolars when increase in height in
not required.
•
When the length has to be increased, the
anterior and lateral guidance has to be considered
and appropriate tooth preparations has to be carried
out to allow for adequate thickness of the laminate at
the incisal or occlusal area.


Provisionalization of laminates
Good provisional help in visualizing the final
outcome and can give adequate information of the
shade and shape of the laminate to the patient and
dentist.
Making and placing provisionals for
laminate preparations is made tedious than
provisionals for crowns. Due to the poor strength of
the thin provisionals, there is a possibility of
breakages during removal and inadequate luting
strength.


There are various methods of making provisionals for
laminate preparations. Composite resin is directly
sculpted on the prepared tooth after spot etching and
bonding at the center of the tooth and cured to get
esthetically acceptable provisionals. This technique is
simple, comparatively less time consuming and cost
effective than others.
Another technique involves making a vocuum
formed shell of clear plastic sheet on a preoperative
cast. The shell with light cured resin is then placed
against the prepared teeth. After the composite is
cured, the shell is separated and finished provisionals
are luted to the preparations.

Try in
Chair side try-in is done to check individuals
veneer fit, collective fit of veneers and the shade of the
composite luting cement that should be used to get the
desired final result.
Individual veneer is tried for marginal fit,
adaptation and retention. Any premature contacts
are relieved at this stage. The veneers should fit in
passively with good contacts and not actively as it
may lead to displacement of some veneers .


Cementation
The patient is viewed periodically for the gingival
response and maintenance regimen. Usually a 3month
check up followed by a 6 monthly check up is
recommended.

Metal ceramic and all-ceramic restorations
Metal ceramic and all ceramic restorations have
excellent esthetic potential.
The metal ceramic
restorations owe their popularity to the simplicity of
bridge construction, durability, strength, marginal
adaptation and versatility of use.

Can be used successfully for various complex clinical
situations like long span bridges, full mouth
rehabilitation as also a number of semi-fixed type of
appliances.
All ceramic restorations are characterized with a
dentin like core which makes it possible to mimic the
translucency of natural teeth.
They are biocompatible with the gingival tissues and exhibit
excellent marginal fit due to newer thermoplastic
processing while some exhibit wear resistance similar
to that of enamel. All ceramic restorations are
indicated for crowns, veneers, inlays, onlays and three
unit bridges with the premolar as the distal most
abutment.

Although all anterior teeth were esthetics is a prime
concern can be indicated for all ceramic
restorations, caution has to be taken when a parafunction, exists, when tooth structure is insufficient
to support the ceramic, in short clinical crowns and
when the lingual preparations is thinner than
0.8mm. In such cases a metal ceramic restorations is
functionally stable and indicated.


Imperatives of tooth preparations
•
Length and taper of the preparation for
retention and resistance.
•
Enough reduction to allow thickness of the
ceramic for excellent esthetics.
Occlusal clearance for occlusal function and anterior
guidance.


Tooth preparations for metal ceramic crowns.
The incisal edge reduction of 1.5mm – 1.8mm and
the occlusal reduction of 1.5mm – 1.7mm with functional
bevel is recommended . Reduction is achieved by using a
wheel diamond on the incisal edge or a round diamond of
known diameter in the occlusal grooves. The incisal edge
reduction is followed by the labial reduction. When
reducing the labial surface of the tooth, the exact contour
must be emulated. This helps to prevent excess removal of
tooth structure which may lead to deficient lingual wall
preparation especially at the incisal aspect. The labial
reduction is achieved in two planes with a round-ended
tapered bur, the first orientation involves the incisal two
thirds of the tooth. www.indiandentalacademy.com

The palatal reduction is carried out allowing sufficient
space for the crown and to re-establish normal occlusal
and protrusive relationships. A pear shaped or rugby
diamond is used to reduce the lingual concavity while the
rest of the cingulum surface is reduced with a round
ended tapered diamond bur.
The proximal reduction involves smooth movements
from the labial surface to the palatal allowing is finished
margin on the proximal surface. Long tapered fissures
can be initially used followed by round ended fissure burs
to achieve desired reduction. Preparations must include
1mmm peripheral shoulder or chamfer with bevel for
ceramometal crowns. The objectives is to achieve a
convergence angle of the axial walls in the range of 6o to
100.

A shoulder with a 90o cavo-surface angle or a stopping
shoulder of 120o is recommended for a adequate support
of porcelain. When the metal margin is shortened for
esthetic reasons, shoulder porcelain requires 1.2mm of
tooth reduction at the margin. The shoulder with a long
bevel is advocated for improved marginal fit but it cannot
be accommodated in shallow gingival sulcus. Hence short
bevel of 0.5mm with a cavo-surface angle of 135o is
preferred.


Chamfer (0.5mm)is the finish line of choice for
metal backing. For porcelain fused to metal
backing, a metal collar on a modified chamfer is
preferred. The palatal chamfer is blended
smoothly with the labial shoulder lingual to the
contact area for good esthetic results. All sharp line
angles within the preparation should be rounded to
reduced stress concentration.


Tooth Preparation for all ceramic crowns.
Although the preparation sequence for all ceramic
restorations is similar to the metal ceramic one, the main
concern for the dentist in the preparation for the all
ceramic crowns should be to minimize the stresses that
could be incorporated on the ceramic in function.
The length of the preparations is important as load
applied from a lingual direction on a short preparations
can lead to severe compression of the labial shoulder
leading to a fracture. The incisal edge is reduced to get flat
area however a reduction in excess of 3mm is avoided. In
some cases a reduction of up to one third of the crown
height may be required to get rid of the thin incisal edge.
The facial reduction iswww.indiandentalacademy.com planes at a depth of
achieved in two
1mm to 1.5mm.

The lingual aspect should be shaped to remove any
uneven surface or sharp line angles and should
incorporeated or sharp line angles and should
incorporate a definite lingual concavity with a high
lingual axial wall whenever the cingulum prominence
and occlusion is favorable. Lingual depth should be
1mm – 1.5mm and should not be less than 0.8 mm. The
proximal preparation is completed with a taper of 6o-8o
and will help in one path insertion. Excessive taper will
cause inadvertent forces on the ceramic and leads to
reduction in flexural strength.


The facial reduction, lingual reduction and the proximal
reduction should end into a well defined shoulder. The
shoulder should not create any undercuts for the
restorations and hence any angle in excess of 90o should be
avoided. The shoulder should not necessarily be uniform
labially, proximally and lingually, as excessive reduction
may be required to do so, compromising on the resistance
and retention form of the preparation. The shoulder is
usually 0.8mm – 1.0mm wide in the labial and lingual and
0.5mm – 0.6mm in the proximal aspect where the ceramic
flares to give sufficient strength. The smooth finish line
should not be steep inter proximally but have a smother
gradient to avoid potential stress area during function.

As a compared to the preparation for metal ceramic
restorations, the finish line for all ceramic restorations
should be a shoulder which is at right angles to the
direction of stress thus increasing the fracture resistance.
In the final preparation all sharp line angles and
undercuts are avoided providing maximum strength and
resistance.
Adequate length of the preparation is
required in order to counter the tipping forces and
increase the surface area for additional retention.


The depth of the facial and lingual shoulder should
be 1.0mm (with a minimum of 0.8 mm) and
interproximally the shoulder can be 0.5mm as the
restoration flares interproximally. A taper of 5o 10o is advisable for conservity and increased
support to the restoration. Increased taper leads
to stress concentration in areas where the support
is lacking.


Try-in
All metal castings are evaluated for margin
integrity, internal fit, stability and adequate space for
ceramic material. Intra occlusal relationship record is
needed in extensive rehabilitation cases. Bisque trial for
ceramic restorations are assessed for location, site and
tightness of proximal contacts, marginal adaptation and
favorable centric and eccentric occlusal contact without
interferences. Besides the shape, contours and color;
adequate
surface characterization is checked and
incorporated.
The trial for all ceramic restorations are assessed
for a passive fit, margins, proximal contacts, stability,
shade, form, characterization and occlusion.

Pre-implant esthetic consideration
In cases of anterior implants in the esthetic zone,
certain specific esthetics criteria have to be considered.
When esthetics is the prime reason for seeking implant
prosthetic treatment, the patient’s upper lip line will be
of extreme importance for the planning of the definitive
superstructure. In patients with a high lip line or
requiring upper lip support from the prosthesis a
removable over denture will more likely fulfill the
demands of function and esthetics than an implant borne
bridge construction.


The single tooth anterior implant situations is of great
concern as the esthetic requirements and expectations
have to be properly balanced keeping in mind anticipated
post-surgical results. The dentist should analyze anterior
single tooth implant situations considering the adjacent
teeth, contra-lateral tooth, probable emergence profile
and presence or absence of inter dental papilla when ever
the active smile exposes enough of gingival tissues.


There are many limitations and contra indications
specific to the maxillary single tooth implant apart
from the routine contra indications associated with
implant therapy. The common causes of a missing
maxillary tooth is traumatic loss, root fracture,
agenesis and periodontal disease. All these leave
some deficiency in the facial bone over the root of
the missing tooth. Majority of the cases of maxillary
single tooth implant in patients with high upper lip
line require bone grafting for ideal esthetics while in
some cases bone grafting would be necessary to
provide adequate healthy peri-implant soft tissue to
maintain optimal hygiene in the cervical region.

Apart from the inadvertent deficiencies in the
facial bone associated with various clinical
situations, the soft tissue form also plays a major
role in the esthetic outcome of single tooth
implants.
In 1989, Misch reported 5 prosthetic
options available in implant dentistry. The first
three options are fixed prosthesis (FP). The next
two options are removable prostheses (RP).


Prosthodontic classification
Type Dentition
FP – 1Fixed Prostheses, replaces only the crown, looks like
a natural tooth.
FP – 2Fixed Prostheses, replaces the crown and a portions
of the root; crown contour appears normal in the occlusal
half but is elongated or hyper contoured in the gingival
half.
FP – 3Fixed Prostheses ; replaces missing crowns and
gingival color and portion of the edentulous site;
prostheses. Most often uses denture teeth and acrylic
gingiva, but may be porcelain to metal.

RP – 4 Removable prostheses ; over denture supported
completely by implant.
RP – 5 Removable Prostheses ; over denture supported by
both soft tissue and implant.
Fixed Prostheses
FP-1 –
FP-1 is a fixed restorations and appears to the
patient to replace only the anatomic crowns of the missing
natural teeth. There usually has been minimal loss of hard
and soft tissues. The final restorations appears very
similar in size and contour to most traditional fixed
prostheses used to restore or replace natural crowns of
teeth.

FP –1 prostheses is most often desired in the maxillary
anterior region. However the width and / or the height
of the crestal bone is frequently lacking, augmentation
is often required before implant placement to achieve a
natural looking crown in the cervical region because
there are no inter dental papillae in edentulous ridges,
gingivoplasty is required after the abutment is
positioned to improve the interproximal gingival
contours. Ignoring this step causes open “back”
triangular spaces (where papillae should usually be
present) when the patient smiles. The bone loss and
lack of inter dental soft tissue complicates the final
esthetic results, especially in the cervical regions of the
crowns.

FP-2 fixed prosthesis restores the anatomic crown and a
portion of the root of the natural tooth. The volume and
topography of the available bone dictate a deficient
vertical implant placement compared with the FP-1
prosthesis, which is more apical compared with the
cemento-enamel function of a natural root. As a result the
incisal edge is in the correct position, but the gingival third
of the crown is over extended, usually apical and lingual
to the position of the original tooth. If the high lip line
during smiling or low lip line during speech are favorable
and do not display the cervical regions, the longer teeth are
usually of no consequence. FP-2 prosthesis that are not
hidden by lip position during smiling or speech can be
solved by using a removable soft tissue replacement device.

The FP-3 is a fixed restorations that appears to replace the
natural teeth crowns and a portion of the soft tissue. As
with the FP-2 prosthesis, the original available bone height
loss decreased by natural resorption or osteoplasty at the
time of implant placement. To place the incisal edge of the
teeth in proper position for esthetics, function, lip support
and speech, the excessive vertical dimension to be restored
required teeth that are unnatural in length. The patient
having high maxillary lip line during smiling and low
mandibular lip during speech, will display the longer teeth
which look unnatural. In the AP 3 the restored gingival
colour and contour give the teeth a more natural
appearance in size and shape and mimic the inter dental
papilla region. The addition of gingival tone acrylic or
porcelain for a more natural appearance is often indicated.

RP-4
It is a removable prosthesis completely supported by
implants and or teeth. It may draw the same appearance
as an FP-1, FP-2, FP-3 restorations.

RP – 5
It is a removable prosthesis combining implant and soft
tissue support. The prosthesis is very similar to traditional
over denture


Factors for favorable implant placement
The physiologic limits with in which the implant
can be placed are governed by the following
•
The space between implant and periodontal
ligament of the adjacent tooth should be 1mm.
•
The average width of periodontal ligament is
0.25mm.


These natural periodontal components will require a space
of 1.25mm on either side of the implant. Thus, mesiodistally the implant diameter is added to this minimum
space required. The facio-lingual requirement. For a
3.5mm implant placed in the anterior region a minimum of
6mm of space mesio-distally has to exits to accommodate
all related components. Ideally, the ridge should be 56mm wide labio lingually, to allow at least 1 mm of the
cortical bone labially and lingually. However, to impart
esthetics in the inter dental papilla region, the distance
between an implant and natural teeth is kept 2mm.


The implant should be 3mm apical to the gingival
margins of the adjacent teeth.
Labio-lingual orientation of the implants helps to
achieve desired emergences profile. Placing the implant
slightly palatally helps the dentist to build up a proper
emergence profile to the crown.
To obtain satisfactory peri-implant gingival
morphology, tissue volume should be 20-25% more than
the estimated need to allow adaptation of gingiva to the
prosthetic reconstruction.


Wider diameter implant will ease the transition of
the implant head to the artificial crown as it emerges
from its soft tissue housing. The wider diameter
implants will not be required to be placed far apical
to the cemento-enamel junction of the adjacent tooth.
Immediate implants help to preserve the hard and
soft tissues, and maintain the emergence profile as in
natural teeth.


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