Some esthetic factors in a smile.

A survey of the characteristics of an open smile was conducted with 454 full-face photographs of randomly selected dental and dental hygiene students. Findings show that an average smile exhibits approximately the full length of the maxillary anterior teeth, has the incisal curve of the teeth parallel to the inner curvature of the lower lip, has the incisal curve of the maxillary anterior teeth touching slightly or missing slightly the lower lip, and displays the six upper anterior teeth and premolars. Consideration of the characteristics may be useful in improving the esthetics of restorations.