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BioMed Research International
Volume 2017 (2017), Article ID 7216120, 8 pages
Research Article

The Effect of Pterygomasseteric Sling’s Area in the Postoperative Stability after Mandibular Setback Surgery

1Graduate Institute of Dental Sciences, School of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
2Department of Oral and Maxillofacial Surgery, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
3Department of Restorative Dentistry and Endodontology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
4Department of Orthodontics, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
5Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung, Taiwan

Correspondence should be addressed to Yu-Chuan Tseng; wt.ten.dees@d97tcy

Received 25 February 2017; Revised 8 August 2017; Accepted 29 August 2017; Published 9 October 2017

Academic Editor: Li Wu Zheng

Copyright © 2017 Chun-Ming Chen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Purpose. The purpose of the present study was to investigate the correlation between the postoperative stability and area of pterygomasseteric sling (PMS). Materials and Methods. Forty patients of mandibular prognathism were treated by isolated mandibular setback. Serial lateral cephalograms were collected (preoperatively [T1], immediately after surgery [T2], and more than 1 year postoperatively [T3]). The postoperative stability (T32) was divided into 3 groups (total, forward, and backward movements). The areas of PMS, immediate surgical changes (T21), postoperative stability (T32), and final surgical change (T31) were analyzed by Student’s t-test, Pearson’s correlation coefficient, and multiple linear regression analysis. Results. The amount of mean setback (T21) was 12.6 mm in total group, 13.8 mm in forward group, and 10.8 mm in backward group. In the total group, postoperative stability (T32) was 0.6 mm forward and reduction area of PMS (T31) was 291 mm2 (17.2%). The reduction area of PMS (T31) was 298.2 mm2 (18%) and 263.1 (15.3%) mm2 in the forward group (3 mm) and backward group (2.4 mm), respectively. However, reduction area of PMS (T31) showed weak correlation with postoperative stability (T32) in all groups. Conclusion. Total and forward groups presented significant correlations between postoperative stability (T32) and amount of setback (T21).