Surgical Uprighting Is a Successful Procedure for Management of Impacted Mandibular Second Molars.

PURPOSE: Impacted mandibular second molars can cause caries and root resorption on adjacent molars and can lengthen orthodontic treatment. Surgical uprighting is one management option. The purposes of this study were to 1) evaluate radiographic outcomes for surgical uprighting of impacted mandibular second molars and 2) propose an etiology for impaction.

MATERIALS AND METHODS: This was a retrospective cohort study of patients who had surgical uprighting of mandibular second molars and had preoperative and at least 12-month postoperative panoramic images and an age- and gender-matched control group of patients undergoing routine orthodontic treatment. Predictor variables included age, gender, impaction type, preoperative angle of impaction, preoperative periodontal bone level distal to an adjacent first molar, posterior eruption space, pathology, and concomitant extraction of the adjacent third molar. Outcome variables were change in impaction type, postoperative periodontal bone levels around the first and second molars, postoperative tooth angle and posterior eruption space, periapical radiolucency, pulpal obliteration, root resorption, and need for extraction. Descriptive statistics were calculated.

RESULTS: The sample and control groups each had 16 patients. The mean ages at the first radiographs were 13 ± 1.1 and 13.19 ± 0.61 years for the treatment and control groups, respectively, and the mean follow-up radiographs were obtained 2.4 ± 1.4 and 2.3 ± 0.82 years later. No preoperative images showed pathologic lesions obstructing eruption. Postoperatively, all uprighted molars were Pell and Gregory type IA. The mean change in the angles of the uprighted teeth was 23.5 ± 16.1° (P < .001). The mean distal bone levels of the adjacent first molar were 3.41 ± 1.52 mm preoperatively and 1.45 ± 0.54 mm postoperatively (improvement, 42.5%; P < .001). The preoperative posterior eruption space was 53.6% longer in the control than in the treatment group (P < .001), and the increase in this distance postoperatively was greater for the treatment group than for the control group (P < .001). Pulpal obliteration (n = 6; 31.5%), periapical radiolucency (n = 2; 10.5%), and root resorption (n = 1; 5.3%) were seen on postoperative radiographs. There were 2 failures (10.5%).

CONCLUSIONS: Surgical uprighting of mandibular second molars is a useful procedure with a low failure rate. Insufficient space for eruption is the likely primary etiology for impaction.