Date of Graduation
School of Dentistry
Background and Objectives: More so than ever, the public is becoming exceedingly aware of esthetics, and will evaluate their treatment outcome based upon the improvement to their smile and overall enhancement of their facial appearance. There exists a debate in orthodontics, as to whether or not extractions harm the profile. The aim of this study was to determine if facial attractiveness is harmed in subjects having completed orthodontic treatment involving the extraction of four premolars both in repose and smiling when viewed in lateral profile. Another objective is to identify any impact upper incisor retraction has on facial attractiveness.
Experimental Design and Methods: A sample of 39 subjects that had completed orthodontic treatment (19 extraction subjects and 20 non-extraction subjects) and had existing pre and post-treatment lateral cephalograms, and lateral repose and smiling photographs, were selected. Orthodontic professionals and laypersons were asked to view a presentation of all of the pre and post-treatment repose and smiling photos of the 39 subjects and asked evaluate facial attractiveness using a visual analogue scale. Amount of incisor retraction was calculated using superimpositions of pre and post-treatment lateral cephalograms. The data was analyzed using paired t-test, ANCOVA, and intra-class correlation coefficient.
Results: For the repose data, a statistically significant difference between the pre-treatment and post-treatment ranking scores (p < 0.05) was observed in 28 of the 39 subjects. 11 of the 39 subjects (28.2%) had a positive mean difference in repose. For the smiling data, a statistically significant difference between the pre-treatment and post-treatment ranking scores (p < 0.05) was also observed in 28 of the 39 subjects. 30 of the 39 subjects (76.9%) had a positive mean difference in smiling. In repose, no statistically significant difference in attractiveness ranking scores between extraction and non-extraction subjects (p > 0.05) was observed. A significant difference in attractiveness ranking scores between orthodontic professionals and laypersons was observed. Orthodontists gave higher attractiveness ranking scores than laypersons (p<0.05) Additionally, a significant difference in attractiveness ranking scores among the different levels of retraction was found. Subjects in the <-2mm and >0 mm retraction groups were judged to be more attractive than subjects who are in the -2 – 0 mm retraction group (p<0.05). In smiling, no significant differences were observed for any of the variables, nor when combined.
Conclusions: Extraction therapy is not harmful to the repose profile or the smiling profile. More subjects were judged to be more attractive post-treatment in smiling than repose. Four premolar extraction made the profile more attractive in repose, whenever the incisors were retracted more than 2 mm. Orthodontists gave higher attractiveness ranking scores than laypersons in repose. There are no differences between judged facial attractiveness and non-extraction vs. extraction therapy, orthodontic vs. layperson, or amount of retraction in smiling.
Chahin, Nicolette R., "Judged Facial Attractiveness of Extraction and Non-Extraction Orthodontic Treatment in Repose and Smiling" (2019). Graduate Theses, Dissertations, and Problem Reports. 3925.