Retained Third Molars With Orthodontics and Orthognathic Surgery

Abstract

The aim of this study was to document the prevalence of retained third molars after orthodontics and orthognathic surgery. Inclusion criteria for these retrospective analyses included all subjects in a longitudinal trial at least 18 years old at enrollment with Class II skeletal problems, treated presurgery with orthodontics followed by orthognathic surgery. Panoramic or lateral cephalometric radiographs were analyzed to assess the presence and relationship to the occlusal plane of third molars and the presence or absence of premolars, recorded at enrollment, presurgery, and postsurgery for each subject. The primary outcome measure was the presence of third molars postsurgery. Explanatory variables included third molar position at the occlusal plane and missing premolars. Because of the few retained third molars postsurgery, analyses are limited to descriptive statistics only. The majority of the 372 subjects were female (80%) and Caucasian (91%). Median age at enrollment was 32.3 years (interquartile range, 27.0-39.6). At entry 145 subjects had at least 1 third molar; 57% of third molars present were at the occlusal plane, and 27% of quadrants in the 145 subjects had at least 1 missing premolar. Sixty subjects had at least 1 third molar postsurgery, 84% of third molars present were at the occlusal plane, and 44% of quadrants had at least 1 missing premolar. Third molars retained after treatment for dentofacial deformity with orthodontics and orthognathic surgery were more likely to be at the occlusal plane and tended to be in quadrants with missing premolars.