Third Molars with Orthodontics and Orthognathic Surgery

Objectives:

Document the prevalence and relationship to the occlusal plane of retained 3rd molars after orthodontics and orthognathic surgery.

Methods:

Inclusion criteria for these retrospective analyses included all subjects at least 18 years old at enrollment with Class II skeletal problems, treated with presurgery orthodontics followed by orthognathic surgery. Panoramic or lateral cephalometric radiographs were analyzed to assess the presence and relationship to the occlusal plane of 3rd molars and the presence or absence of premolars, recorded at baseline, presurgery and post-surgery for each subject.

The primary outcome measure was the presence of 3rd molars post-surgery. Predictor variables included demographics, 3rd molar position at the occlusal plane, and missing premolars. Because of the few retained 3rd molars post-surgery, analyses are limited to descriptive statistics only.

Results:

The majority of the 372 subjects were female, 80%, and Caucasian, 91%. Median age at enrollment was 32.3 years (IQ 27.0-39.6). At entry 145 subjects, 38%, had at least one 3rd molar; 57% of 3rd molars were at the occlusal plane and 27% of quadrants had at least one missing premolar. Post-surgery 60 subjects, 17%, had at least one 3rd molar; 84% of 3rd molars were at the occlusal plane, and 44% of quadrants had at least one missing premolar. Only 9% of the maximum possible number of 3rd molars were retained post-surgery.

Conclusions:

Though few 3rd molars are retained after orthognathic surgery, most are at a useful functional position, the occlusal plane.

Funding Sources:

Oral and Maxillofacial Surgery Foundation, American Association of Oral and Maxillofacial Surgeons, Dental Foundation of North Carolina. DE005215.