A correlative study to evaluate the effect of various skeletal and dentoalveolar parameters on smile esthetics in different malocclusion groups

Introduction: The smile is one of the most effective means by which people convey their emotions and from a social standpoint, it is viewed frontally more often than in profile. Smiles can be either posed or spontaneous. Peck and Peck classified smiles as Stages I and II, and Ackerman et al. classified smiles into two basic types: the social smile and the enjoyment smile. Each type involves a different anatomic presentation of the elements of the display zone. Smile characteristics are determined by the interplay of static and dynamic relationships between the dentoskeletal and soft-tissue components of the face. Hence, a study was planned to understand the influence of various skeletal and dentoalveolar parameters on smile esthetics in different malocclusion groups. Materials and Methods: Sixty subjects in the age range of 17–25 years were selected and skeletally divided into Groups I and II on the basis of beta angle, ANB angle, and Wits appraisal. Group II was further subdivided into two groups on the basis of Angle's classification of the malocclusion. Various skeletal and dental parameters were measured on cephalogram and smile measurements were made on facial photographs in Adobe Photoshop. Various statistical tests were applied for assessment and comparison of various skeletal and dentoalveolar parameters and their correlation with smile esthetics were in different malocclusion groups. Results: Upper lip length was maximum in Class II div 2 malocclusion patients and least in Class I malocclusion patients. It was maximum in horizontal growth pattern patients. It decreased with the increase in proclination of upper incisors. Maxillary incisal display at rest and smile was maximum in Class II div 1 malocclusion patients and least in Class II div 2 malocclusion patients. It was maximum in vertical growth pattern individuals. It increased with the increase in proclination of upper incisors. A similar tendency was shown by the Morley ratio and modified smile. Lip competency was maximum in Class II div 2 patients and minimum in Class II div 1 patients. It was maximum in horizontal growth pattern patients. Proclination of the incisors decreased the lip competency. Conclusions: Different skeletal patterns exhibit their characteristic smile features. Orthodontic treatment should be planned considering the correlation of skeletal and dental effects on smile esthetics.