Profile changes in orthodontic patients treated with mandibular advancement surgery

Abstract

The potential to improve facial esthetics is often the deciding factor in treatment planning of borderline orthodontic patients who can be treated with either orthognathic surgery or dental camouflage. The purpose of this study was to determine the degree of skeletal and soft-tissue Class II disharmony necessary before a significant esthetic benefit is derived from mandibular advancement surgery. Twenty laypeople, 20 orthodontists, and 20 oral surgeons rated the attractiveness of before and after treatment profiles of 20 mandibular advancement patients using a 5-point Likert scale. The Spearman rank correlation tested for relationships between amount of profile change and varying pretreatment ANB and profile angles. Plots of the distribution of profile changes with varying ANB and profile angles were then examined. There was a tendency for inverse correlations between profile change and profile angle, and for positive correlations between profile change and ANB angles, but only the relationship between profile change and ANB angles judged by the orthodontists was statistically significant (P <0.05). Orthodontists, oral surgeons, and laypeople found that profiles consistently improved when profile angles were < or = 159 degrees, < or = 158 degrees, and < or = 157 degrees, respectively. Orthodontists and oral surgeons found profiles consistently improved when ANB angles were > or = 5.5 degrees and > or = 6.5 degrees, respectively, whereas laypeople showed no trend between ANB angle and profile change. The incidence of having less desirable profiles after treatment was 2.6 to 5.0 times higher when the pretreatment profile angles were larger than the threshold profile angles, and 4.5 to 7.9 times higher when the pretreatment ANB angles were less than threshold ANB angles. Pretreatment profile angles < 160 degrees and ANB angles > 6 degrees are necessary for profiles to be consistently perceived as improved after surgery and to minimize the incidence of the profile worsening after treatment.