Comparison of Posttreatment Stability Between Mandibular Setback Surgery-Early and Conventional Surgery in Class III Patients: A 4.6-Year Follow-Up.

OBJECTIVES

This retrospective study aims to compare long-term stability between the mandibular setback surgery-early (MSE) approach, involving minimal orthodontics, and the mandibular setback conventional surgery (MCS) approach, involving sufficient orthodontics, in Class III patients with mandibular prognathism.

METHODS

Among 210 patients who underwent orthognathic surgery, a total of 40 subjects were enrolled based on standardized inclusion criteria: only mandibular surgery, <5 mm setback difference between right and left of the mandible, orthodontics with fixed appliances, and more than 2 years of follow-up after treatment. These patients were allocated to the MSE (n = 20) and MCS groups (n = 20) according to the duration of presurgical orthodontics. Changes in cephalometric measurements were compared between the MSE and MCS groups before surgery (T0), 1 month after surgery (T1), at the end of treatment (T2), and posttreatment retention (T3).

RESULTS

The MSE and MCS groups had a mean presurgical orthodontic duration of 2 and 9.5 months, respectively. From T1 to T2, the MSE group showed a significantly larger forward movement of the mandible than the MCS group (2.1 versus 0.7 mm; P < 0.001). In addition, from T2 to T3 (average 4.6 years), the MSE group presented anterior relapse of 0.6 mm in the mandible, but there were no statistically significant intergroup differences.

CONCLUSION

Although the MSE group showed greater postsurgical forward mandibular relapse than the MCS group, the two groups exhibited similar skeletal and dental stability during the posttreatment retention.