Evaluation Of Posed Smile Characteristics Indicators’Aesthetic Range

Objective:To investigate correlation of smile esthetics and the six posed smile characteristic index which can be controlled by orthodontics,to obtain the acceptable range for people of posed smile characteristic index,and to find differences between the orthodontists and the laypersons on smile evaluation.all these done is in order to supply diagnostic and therapeutic basis for orthodontic treatment,and to instruct orthodontists to bring patients a charming smile.At the same time,to deeply explore the smile arch,one of the six posed smile characteristic index,that is,to find whether female face shape has influence on smile arch esthetics.Method:The200subjects included in the study consist of100experienced orthodontists and100laypersons.Both two frontal posed smile photographs of man and woman were changed by several smile characteristic indexes, including the amount of incisor exposure, amount of gingival display,smile arc, buccal corridor fill, horizontal inclination of maxillary occlusal plate and distance from lower lip to maxillary incisor. All the subjects were desired to evaluate each images according to their own aesthetic standard.Analysis was used to analyse the scores and the relevant index.Choose a photo of female standard posed smile, and change it to three groups by the Photoshop software,according to the face shape,which consists of pointed round face, ovoid face,and quadrate round face.Each group have a series of smile arch radian. The400subjects included in the study were desired to evaluate each images according to their own aesthetic standard.Results:The scores have a positive correlation with the amount of incisor exposure and the smile arc(P<0.05). but have a negative correlation with the amount of gingival display, the buccal corridor fill, the horizontal inclination of maxillary occlusal plate and the distance from lower lip to maxillary incisor(P<0.05). Each acceptable range for the amount of incisor exposure, amount of gingival display,smile arc, buccal corridor fill, horizontal inclination of maxillary occlusal plate and distance from lower lip to maxillary incisor,was75%-100%(male and female),0-2mm(male),0-3mm(female).50%-100%(male and female),0-15%(male),0-20%(female),0-6°(male and female),0mm(male and female)(P<0.05)。And there was perception difference between the orthodontists and the laypersons on smile arc, buccal corridor fill and horizontal inclination of maxillary occlusal plate (P<0.05),but no difference between the amount of incisor exposure, amount of gingival display and distance from lower lip to maxillary incisor (P>0.05).When the smile arc have the same radian with the face shape,the images’ score is the highest.Conclusions:The relative position of lip,tooth and gingiva has a significant influence on smile esthetics. Posed smile analysis should be an important aspect of orthodontic diagnosis and treatment planning. Orthodontists should not create smiles in their own eyes,but talk over with the patient to decide treatment plan.