The esthetics of the smile: a review of some recent studies.

PURPOSE This article reviews recent research on the esthetics of the smile, covering the attractiveness of the smile, the effect of aging on the smile, oral condition and the smile, personality and smile, and smile exercises. MATERIAL AND METHODS The subjects were Koreans with normal occlusion. Photographs of a full smile were taken and the esthetic quality of the subjects' smiles was estimated. Smile scores were correlated with oral condition, personality, the practice of smile exercises, and elements of the smile, such as the position of the lip in a smile. The personality of the subjects was assessed by means of a Sixteen Personality Factor Questionnaire. Gibson's smile exercises were used to investigate the effect of smile exercise. RESULTS In an attractive smile, the full shape of the maxillary anterior teeth was shown between the upper and lower lip, the upper lip curved upward or was straight, the maxillary anterior incisal curve was parallel to the lower lip, and teeth were displayed to the first molar. The amount of maxillary incisal exposure gradually decreased with age, accompanied by a gradual increase in mandibular incisal exposure. Personality traits such as warmth, calmness, extroversion, and low anxiety were closely related to an attractive smile. Smile exercises were an effective means of improving the esthetic level of the smile if patients exercised continuously. CONCLUSION An attractive smile is important for esthetic treatment. The lip position, oral condition, personality traits, and smile exercise affect the esthetics of the smile.