PRESENTED BY - DR. JICKY RAJANI ST YESR PGDEPT. OF ORTHODONTICS

• Smile is one of the most important expression contributing to facial attractiveness.

• With patients becoming increasingly conscious of a beautiful smile, smile esthetics has become the primary objective of orthodontic treatment.

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

*Ackerman MB, Ackerman JL. Smile analysis and design in the digital era. J Clin Orthod 2002;36:221-36.

• Smile analysis should involve evaluation of certain elements in specific sequence * :-

Dento-facial analysis

Dento-labial analysis

Dento-gingival analysis

Dental analysis.

*Mc Laren EA, Cao PT. Smile analysis and esthetic

design: “In the zone”. Esthet Dent 2009;5:44-8.

A. DENTO FACIALi. Midline

B. DENTO LABIALi. Incisor displayii. Smile arciii. Smile symmetryiv. Buccal corridor

C. DENTO GINGIVALi. Gingival healthii. Height and contour of gingiva

D. DENTAL i. Contacts and connectorsii. Embrasuresiii. Crown height and widthiv. Mesiodistal width

A.DENTO-FACIAL ANALYSIS

i. MIDLINE

• The starting point of the esthetic treatment

plan is the facial midline.

• One of the goals of the orthodontic treatment is to achieve maxillary and mandibular midlines that are coincident-both with each other and with the facial midline.

• The most practical guide to locate the facial midline is to use two anatomical landmarks as references* :-

Nasionthe 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.

• * Morley J, Eubank J. Macroesthetic elements of smile design. J Am Dent Assoc 2001;132:39-45.

• Ideally the maxillary central incisor midline should coincide with the facial midline.

• However if it is not possible, then the midline between maxillary central incisors should be strictly vertical and parallel to the facial midline.

B. DENTO-LABIAL ANALYSIS

i. MAXILLARY INCISOR DISPLAY AT REST

• The average maxillary incisor display at rest is 1.91 mm in men and 3.40 mm in women.

• The amount of incisor show at rest is the most important esthetic parameter because decreased incisor display is characteristic of ageing.

•• This steady decline in maxillary tooth exposure at

rest with aging, is accompanied by an increase in mandibular incisor display

Maxillary incisor display on smile / Lip line

• The lip line is the amount of vertical tooth exposure on smiling i.e the height of the upper lip relative to the maxillary central incisors.

• The lip line is optimal when the upper lip reaches the gingival margin, displaying the total cervico-incisal length of the maxillary central incisors, along with the interproximal gingivae while smiling

• A high lip line exposes all of the clinical crowns plus a contiguous band of gingival tissue

• A low lip line displays <75% of the maxillary anterior teeth

• Because female lip lines are an average 1.5 mm higher than male lip lines, 1-2 mm of gingival display at maximum smile could be considered normal for females.

ii. SMILE ARC

• The smile arc is defined as the relationship of the contour of the incisal edges of the maxillary anterior teeth relative to the curvature of lower lip during a social smile.

*Dong JK, Jin TH, Cho HW, Oh SC. Th e esthetics of the smile: A reviewof some recent studies. Int J Prosthodont 1999;12:9-19.

Smile arcs are of three types:-

Straight

Consonant

Non consonant

Consonant smile arc has the curvature of incisal edges of the maxillary anterior teeth parallel to the upper border of the lower lip.

For consonant smile arc, the centrals should appear slightly longer or, at least, not any shorter than the canines along the incisal plane

• Straight smile arc is that in which the incisal edges of the maxillary anterior teeth are in a straight line to the upper border of the lower lip.

• Reverse or non-consonant smile arc is the one in which the incisal edges of the maxillary anterior teeth are curved in reverse to the upper border of the lower lip.

• Reverse smile arc occurs when the centrals are shorter than the canines along the incisal plane which can be due to occlusal malfunction or loss of vertical dimension.

• Parallel and straight smiles provide better esthetic than reverse smile.

iii. SMILE SYMMETRY

• An asymmetry in the smile can be due to:-

Asymmetric smile curtain

Transverse cant of the maxillary occlusal plane.

• Transverse cant can be due to different amounts of tooth eruption on the right and left sides or skeletal asymmetry of mandible resulting in compensatory cant of maxilla.

• In an asymmetric smile curtain, there is a difference in the relative positioning of the corners of the mouth in the vertical plane .It can be assessed by the parallelism of the commissural and pupillary lines

iv. BUCCAL CORRIDOR

• Buccal corridor refers to dark space (negative space) visible during smile formation between the corners of the mouth and the buccal surfaces of the maxillary teeth.

• It is measured from the mesial line angle of the maxillary first premolar to the interior portion of the commissure of lips.

• It is represented by a ratio of th intercommissure width divided by the distance from the first premolar to first premolar

• Buccal corridor is directly influenced by arch form.

• The ideal arch is broad and conforms to a U shape and is more likely to fill the buccal corridors than narrow and constricted arch.

• Buccal corridor should be kept to a minimum as it is unattractive, but at the same the buccal corridor should not be completely eliminated.

C. DENTO-GINGIVAL ANALYSIS

i. GINGIVAL HEALTH

• It is of utmost importance that the gingival tissues are in a complete state of health prior to the initiation of any treatment

ii. HEIGHT, SHAPE AND CONTOUR OF THE GINGIVA

• Establishing the correct gingival levels for each individual tooth is the key in the creation of pleasing and harmonious smile.

The gingival margins of the central incisors should be at the same level or slightly incisal to that of the canines

the gingival margins of the lateral incisors should be towards incisal when compared to central incisors and canines.

• The discrepancies in the levels of gingival margin may be caused by

attrition of the incisal edges

ankylosis due to trauma in a growing patient

severe crowding

• The gingival margins can be leveled by orthodontic intrusion or extrusion or by periodontal surgery, depending on the lip line, the crown heights, and the gingival levels of the adjacent teeth.

• Gingival shape implies the curvature of the gingiva at the margin of the tooth.

• In an esthetic smile, the volume of the gingiva from the apical aspect of the free gingival margin to the tip of the papilla is about 40-50% of the length of the maxillary anterior tooth and fully fills the gingival embrasure.

D. DENTAL ANALYSIS

i. CONTACTS AND CONNECTORS

• There is distinction between a connector space and a contact point.

• The contact points between the anterior teeth are generally smaller areas that can be marked by passing articulating ribbon between the teeth.

• The connector is a large, broad area that can be defined as the zone in which two adjacent teeth appear to touch.

• The contact points of maxillary teeth move progressively gingivally from the central incisors to the premolars, so that there is a progressively larger incisal embrasure, whereas connectors decreases in size from the centrals posteriorly.

• An esthetic relationship exists between the interproximal connectors of anterior teeth that is referred to as the 50-40-30 rule

ii. EMBRASURES

• The incisal embrasures are the triangular spaces incisal to the contact point. Ideally these should display a natural, progressive increase in size or depth from the central to the canine.

• Ideally the embrasures show progressive increase in size or depth from the central to the canine.

• The contact point moves apically as we proceed from central to canine

• The individuality of the incisors will be los t if their incisal embrasures are not properly developed.

• Also, if the incisal embrasures are too deep, it will tend to make the teeth look unnaturally pointed.

• As a rule, a tooth distal to incisal corner is more rounded than its mesio incisal corner.

iii. CROWN HEIGHT AND WIDTH

• Crown height combined with percentage of incisor display is the deciding factor in the amount of tooth movement required to improve the smile index.

• The vertical height of the maxillary central incisors in the adult is normally between 9 and 12 mm.

• Most references specify the central incisors to have about an 8:10 width/height ratio.

• In one of a recent study the optimal width-to-length ratio for the maxillary central zone was found to be between 75% and 85% of the length.

• Smiles with these values were most often considered “esthetic to highly esthetic.”

iv. MESIO-DISTAL WIDTH

• The centrals must be the dominant teeth in the smile and they must display pleasing proportions.

• They are the key to the smile.

• The shape and location of the centrals influences or determines the appearance and placement of the laterals and canine

• The apparent width of the lateral incisor should be 62% of the width of the central incisor.

• The apparent width of the canine should be 62% of that of the lateral incisor.

• The apparent width of the first premolar should be 62% of that of canine.

• This ratio of recurring 62% proportions appears in a number of other relationships in human anatomy is referred to as the “Golden proportion.”

CONCLUSION

• Although the concept of smile analysis is not new but is often not incorporated in orthodontic treatment planning.

• It is therefore emphasized that all the above discussed elements of smile analysis should be considered as guidelines and reference points for beginning esthetic evaluation, treatment planning and subsequent treatment .

“ANYBODY THAT SMILES AUTOMATICALLY LOOKS BETTER