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Updated: May 8, 2026
A Postoperative Evaluation Guideline for Computer-Assisted Reconstruction of the Mandible
Published on: January 28, 2020
Postsurgical stability after mandibular setback surgery with minimal orthodontic preparation following upper premolar
Jong-Wan Kim1, Nam-Ki Lee, Pil-Young Yun
1Former Assistant Professor, Department of Orthodontics, Seoul National University Bundang Hospital, Seongnam, South Korea; Private Practice, Seongnam, South Korea.
Purpose:
To compare patterns of surgical change and postsurgical relapse between patients with mandibular setback surgery with minimal orthodontic preparation (MS-MO) and those with sufficient orthodontic preparation (MS-SO) after upper premolar extraction (UPE).
Materials And Methods:
Twenty-six patients were allocated to 2 groups based on the duration of presurgical orthodontic preparation: MS-MO/UPE (n = 15; 5.53 ± 3.14 months) and MS-SO/UPE (n = 11; 13.00 ± 5.33 months). Lateral cephalograms were taken during the initial examination (T0), at splint removal (4 weeks after surgery; T1), and immediately after debonding (T2). To evaluate the surgical changes (T1 vs. T0) and relapse (T2 vs. T1), linear, angular, and dental measurements were used and analyzed using paired t test and independent t test.
Results:
Although there was no significant difference in skeletodental patterns at T0 between the 2 groups, the MS-MO/UPE group showed a significantly larger amount of mandibular setback than the MS-SO/UPE group from T0 to T1. The 2 groups exhibited significant anterior and superior movement of the mandible from T1 to T2. However, the MS-MO/UPE group manifested greater counterclockwise rotation and forward movement of the mandible than the MS-SO/UPE group. Owing to such relapse of the mandible, the MS-MO/UPE group exhibited limited retraction of the upper incisors, whereas the MS-SO/UPE group showed slight labioversion of the upper incisors.
Conclusion:
Compared with the MS-SO/UPE group, the MS-MO/UPE group showed a larger amount of surgical setback and greater postsurgical counterclockwise rotation and forward movement of the mandible.
