Retraction and rotation of the mandibular arch with buccal shelf bone screws to resolve Class III skeletal malocclusion
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Objectives:
To elucidate the retraction effectiveness of extra-alveolar mandibular buccal shelf (MBS) bone screws anchorage relative to the presence of mandibular third molars and ANB angle in Class III patients.
Materials And Methods:
This retrospective study included 45 patients (mean age = 22.2 ± 6.7 years) treated with bilateral MBS stainless steel bone screws (2 × 12 mm). Patients were subgrouped based on mandibular third molar status and ANB angle (≤-2° vs > -2°). Pretreatment and posttreatment cephalograms were superimposed and analyzed. Statistical tests included analysis of variance, paired and independent t-tests, and linear regression.
Results:
Mean retraction of mandibular first molars and incisors was 1.86 ± 1.36 mm and 2.89 ± 1.64 mm, respectively, over an average of 9.0 months. Retraction ≥ 3 mm was significantly associated with treatment durations ≥ 12 months (P < .001). No significant differences in retraction outcomes were found among third molar subgroups. The severe malocclusion group (ANB ≤ -2°) showed greater molar retraction and overjet increase. A moderate positive correlation was found between molar crown retraction and retraction duration (R2 = 0.282, P < .001).
Conclusions:
MBS bone screws provide effective, minimally invasive anchorage for mandibular whole-arch retraction in Class III patients. Treatment outcomes are not hindered by third molars in adolescents, and longer retraction duration enhances distal movement.
