Smile esthetics after orthodontic treatment with and without extraction of four first premolars.

Standardized frontal photographs were taken of the face during smiling for 60 retention patients; 20 from each of three different private orthodontic practices. Thirty patients had been treated with extraction of four first premolars, and 30 with full edgewise appliances but no extractions. Smile esthetics were judged by a panel of 10 laypersons. There were no significant differences in the mean esthetic score of extraction and nonextraction patients. The only variable that strongly predicted the esthetics of extraction patients was the office in which they were treated, indicating that there may be a significant difference among practitioners in the esthetic outcome of four premolar extraction treatment. Variables related to the "buccal corridor" or other measures of the relationship between the width of the dentition and the width of the mouth during a smile showed no relationship to extraction esthetics. The results indicate that there is no predictable relationship between the extraction of premolars and the esthetics of the smile.