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Journal of the Canadian Dental Association

252

May 1999, Vol. 65, No. 5

1 9 9 9   C D A

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W

hen it comes to expressing emotions, members of

widely different cultures have much in common.

If people from various countries are shown a pho-

tograph of a happy, smiling face they usually agree in their

interpretation. They also tend to concur over disgust, surprise,

sadness, anger, fear and contempt. Such findings imply that

beneath all the cultural complexity of mankind, there is a core

of basic emotional expression that is understood all over the

world.

1,2

As best said by Darwin, it appears that we all smile in

the same language.

Facial expressions have evolved over time, with changes in

musculature around the mouth allowing for the development

of new signals. For example, changes in the zygomaticus

major, which moves the corners of the lips upward and back-

ward, created our characteristic smile.

1

Today, the smile is easily the most recognized expression,

used to convey to our fellow human beings a sense of com-

passion and understanding. The smile may well be the corner-

stone of social interaction.

As a result of this evolution, the smile necessitates a natural

architectural pattern that is pleasing to others. Our responsi-

bility as dentists is to face this new challenge and acquire the

skills to identify various smile patterns. Only with proper pre-

treatment diagnostics and a set of objectively measurable

parameters can we begin to deal with rehabilitating our

patients’ smiles.

Identifying Smile Patterns

Dentistry needs to develop a methodical classification to

identify various smile patterns. Fundamental to our treatment

are terms and classifications that standardize the myriad of indi-

vidual dental problems and interpret them into vocabulary

shared not only by patients and dentists, but by staff, laboratory

personnel and regulatory bodies. Several branches of dentistry

use classification systems; orthodontic occlusion, for example, is

defined by a relatively simple three-type classification system.

Similarly, periodontal furcations, traumatic tooth fractures and

complicated oral facial surgeries are easily grouped and indexed. 

Smile Styles

Although there are millions of different smiles — essen-

tially as many as there are individuals — three basic smile pat-

terns can be identified. Plastic surgeons, tasked with rehabili-

tating smiles, have generally identified the following neuro-

muscular smile patterns:

3

1. The  commissure smile is the most common pattern, seen in

approximately 67% of the population. In this smile, typically

thought of as a Cupid’s bow, the corners of the mouth are first

pulled up and outward, followed by the levators of the upper

lip contracting to show the upper teeth. In this classic smile

pattern, the lowest incisal edge of the maxillary teeth are the

central incisors. From this point, the convexity continues

superiorly with the maxillary first molar being 1 to 3 mm

higher than the incisal edge of the centrals. A spontaneous

smile results in a maximum movement of the commissure

from 7 to 22 mm. Likewise, the average direction of move-

ment of the commissure is 40 degrees from the horizontal

(range 24 to 38 degrees). The direction of movement of most

smiles is to the helix-scalp junction. When comparing the left

to the right side, a large difference may exist in the extent of

movement, but there is only a relatively slight discrepancy in

the actual direction of movement when comparing left to

right.

4

Personalities with recognizable commissure smiles

include Jerry Seinfeld, Dennis Quaid, Jennifer Aniston,

Frank Sinatra, Jamie Lee Curtis and Audrey Hepburn.

2. The cuspid smile is found in 31% of the population.

3

The

shape of the lips are commonly visualized as a diamond.

This smile pattern is identified by the dominance of the

levator labii superioris. They contract first, exposing the

cuspid teeth, then the corners of the mouth contract to pull

the lips upward and outward. However, the corners of the

mouth are often inferior to the height of the lip above the

maxillary cuspids. Often there is a similar inferior turn of

the maxillary premolars as opposed to the continuous con-

vexity of a commissure smile. This “gull wing” effect is sil-

houetted by the gingival tissues, which correspondingly

mimic the shape of the upper lip. In this smile pattern, the

maxillary molars are often at or below the incisal edge of

the central incisors. Eminent personalities with cuspid

smiles include Elvis, Tom Cruise, Drew Barrymore, Sharon

Stone, Linda Evangelista and Tiger Woods.

3. The complex smile characterizes 2% of the population.

3

The

shape of the lips are typically illustrated as two parallel

chevrons. The levators of the upper lip, the levators of the

corners of the mouth, and the depressors of the lower lip

contract simultaneously, showing all the upper and lower

The Classification of Smile Patterns 

•

Edward Philips, BA, DDS 

•

© 

J Can Dent Assoc 1999; 65:252-4

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May 1999, Vol. 65, No. 5

253

Journal of the Canadian Dental Association

The Classification of Smile Patterns

teeth concurrently. The key characteristic of this smile is the

strong muscular pull and retraction of the lower lip down-

ward and back. In this smile pattern both maxillary and

mandibular incisal planes are generally flat and parallel. Some

celebrated personalities with complex smiles include Julia

Roberts, Marilyn Monroe, Will Smith and Oprah Winfrey.

Although the basis for smile styles is neuromuscular, indi-

viduals can usually employ all smile patterns. Often a smile has

been programmed by habit or by an inappropriate positioning

of the underlying hard tissues. Restoring the smile can give

individuals new confidence and can often change their neuro-

muscular programming.

3

Stages of a Smile

There are four stages in a smile cycle:

Stage I

lips closed

Stage II

resting display

Stage III natural smile (three-quarters)

Stage IV expanded smile (full)

Of course, smiles vary and are unique to each individual.

Many smiles do not differ much from a natural smile to an

expanded smile. In these cases, treatment can often be re-

stricted to the maxillary or mandibular anterior front six teeth.

Other smiles have a very apparent discrepancy in display

between these two stages, in which case, the treatment plan to

esthetically improve the smile must be extended.

5

Types of Smiles

There are five variations in which dental and/or periodon-

tal tissues are displayed in the smile zone:

Type 1

maxillary only

Type 2

maxillary and over 3 mm gingiva

Type 3

mandibular only

Type 4

maxillary and mandibular

Type 5

neither maxillary nor mandibular

In the vast majority of cases, people will be categorized

under a single type, although it is possible to combine types, if

necessary. For instance, a patient may have a complex smile

prominently showing maxillary and mandibular teeth and have

a maxillary “gummy” smile displaying more than 3 mm of gin-

giva. This odd smile pattern would be a type 2, 4.

Smile Classification System

The above categories can be systematically combined to cre-

ate a standardization of terms objectively describing various

smiles. Style, stage and type together provide a complete, easy

and concise description for smile classification. Patients and den-

tists would both benefit from a nomenclature that is recognizable

by definition. For example, the most common smile is a com-

missure smile, stage III, type 1. Examples of each smile pattern

with corresponding classification can be seen in Figs. 1, 2 and 3.

Summary

Although “smile therapy” is still in its infancy, society has

already placed a great demand on dentists to evaluate and treat

Fig. 1: Preoperative smile: Commissure, Stage III, Type 1.

Postoperative: 15 porcelain veneers/crowns; Commissure, Stage IV,

Type 1.

Fig. 3: Preoperative smile: Complex, Stage IV, Type 2. Postoperative:

gingivectomy and 20 porcelain veneers; Commissure, Stage III,

Type 1.

Fig. 2: Preoperative smile: Cuspid, Stage III, Type 4. Postoperative:

6 porcelain veneers; Cuspid, Stage III, Type 4.

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Journal of the Canadian Dental Association

254

May 1999, Vol. 65, No. 5

Philips

smiles. The smile classification scheme and vocabulary pre-

sented in this article will aid in discussions between patient

and dentist regarding esthetic treatment. 

a

Acknowledgment: The author is grateful for his patients  permission

to reproduce the photographs used in this article.

Dr. Philips has a private practice in esthetic dentistry in Toronto.

Reprint requests to: Dr. Edward Philips, The Studio for Aesthetic

Dentistry, 700 University Ave., Toronto ON, M5G 1Z5.

The views expressed are those of the author and do not necessarily reflect

the opinion or official policies of the Canadian Dental Association.

References

1. Young S. Human facial expressions. In: Jones, S. and others, editors.

The Cambridge Encyclopedia of Human Evolution. 1992. p. 164-5.

2. Kingdon J. Facial patterns as signals and masks. In: Jones, S. and oth-

ers, editors. The Cambridge Encyclopedia of Human Evolution. 1992.

p. 161-5.

3. Rubin LR. The anatomy of a smile: its importance in the treatment of

facial paralysis. Plast Reconstr Surg 1974; 53:384-7.

4. Paletz JL, Manktelow RT, Chaban R. The shape of a normal smile:

implications for facial paralysis reconstruction. Plast Reconstr Surg 1993;

93:784-9.

5. Janzen EK. A balanced smile — a most important treatment objective.

Am J Orthod 1977; 72:359-72.

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May 1999

This month’s package contains a selection of reading

materials on tobacco and oral health. It is available to

CDA members for $5.00 plus applicable tax.

A complete list of information packages is available upon

request by calling 1-800-267-6354 or can be easily accessed

on the CDA Web site at www.cda-adc.ca. Once inside our

site, please log into the “CDA Members” area and click on

“Resource Centre” to view the list of packages.

New acquisitions

Nield-Gehrig, J.S. Periodontal instrumentation for the practi-

tioner. Williams & Wilkins, 1999.

Braun, R.J. and Cutilli, B.J. Manual of emergency medical treat-

ment for the dental team. Williams & Wilkins, 1999.

Fischer, J. Esthetics and prosthetics: an interdisciplinary consider-

ation of the state of the art. Quintessence, 1999.

CDSPI. Wills, taxes and your practice. 1999 [3-hour video].

Massad, Joseph P. Predictable complete dentures. 1997 [2 videos,

2 hours each].