The purpose of this study was to evaluate smile esthetics on photographs of orthodontic patients treated with or without extraction of premolars, by four different panels of orthodontists, orthodontic residents, dentists and lay people. The material for this investigation was obtained from 50 patients (25 extraction and 25 non-extraction) between 15-20 years of age. Each subject was asked to give a pleasing and natural smile for a standardized frontal view. Smile esthetics was evaluated by a panel of 20 orthodontists, 20 orthodontic residents, 20 dentists and 20 laypeople on black and white photographs (10×15 cm). The judges were asked to give each photograph a whole number score between 1 and 5. Additional descriptive data were calculated from each photograph. The effect of different panels and treatment modalities on the scores given to the photographs was evaluated by a two way analysis of variance, which revealed that both variables had an impact on the scores. The judges who gave the highest scores were the lay people, followed by orthodontists and orthodontic residents. Visible dentition width/smile width, and maxillary inter-canine width/visible dentition width ratios indicated a significant difference between extraction and non-extraction smile photographs. The non-extraction smile photographs were rated higher than the extraction photographs by all of the judge groups. When the ratios were evaluated in order to analyze this outcome, the significant difference between the extraction and non-extraction groups in Ratio 3 pointed to the presence of dark buccal corridors in the extraction group. Additionally, the evaluation of the ratios emphasized the importance of the visibility of the posterior maxillary teeth on smile esthetics.

Keywords: Smile esthetics, Buccal corridor, Extraction treatment, Non-extraction treatment