OBJECTIVEThe characteristics of lip-mouth region including the soft and hard tissues in smiling position with frontal fixed position photographic computer-aided analysis were studied.

METHODSThe subjects were 80 persons (40 male and 40 females, age range: 17 to approximately 25 years) with acceptable faces and individual normal occlusions. The subjects were asked to take maximum smiling position to accept photographic measurement with computer-aided analysis.

RESULTSThe maximum smile line could be divided into 3 categories: low smile line (16.25%), average smile line (68.75%), and high smile line (15%).

CONCLUSIONThe method adopting maximum smiling position to study the lip-month region is reproducible and comparable. This study would be helpful to provide a quantitative reference for clinical investigation, diagnosis, treatment and efficacy appraisal.

Adolescent ; Adult ; Anthropometry ; Dental Occlusion ; Female ; Humans ; Lip ; anatomy & histology ; Male ; Mouth ; anatomy & histology ; Smiling ; Tooth ; anatomy & histology