What question did this study set out to answer?

This study aims to determine if mandibular angle resection during setback surgery improves skeletal stability in Skeletal Class III malocclusions.

May 25, 2026JPRAS Open0 citationsOpen Access

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Effect of Pterygomasseteric Sling Shortening via Mandibular Angle Resection on Postoperative Skeletal Stability in Skeletal Class Iii Malocclusions Treated With Mandibular Setback Surgery

LHLe Tan Hung PKPham Trinh Quoc Khanh LLLe Duc Lanh

Key Points

This study aims to determine if mandibular angle resection during setback surgery improves skeletal stability in Skeletal Class III malocclusions.
Prospective randomized controlled study involving 20 patients with Skeletal Class III malocclusion.
Patients were divided into two groups: one underwent bilateral sagittal split ramus osteotomy with angle resection, and the other received isolated ramus osteotomy.
Lateral cephalometric tracings were used to measure skeletal changes at Point B, Pogonion, and Menton during the postoperative phase.
The control group experienced anterior relapse at Point B (+1.35 ± 1.50 mm) and Pogonion (+0.81 ± 2.92 mm).
The experimental group showed posterior settling at Point B (-1.44 ± 1.93 mm) and Pogonion (-1.14 ± 4.06 mm).
Mandibular angle resection effectively reduces tension from the pterygomasseteric sling, improving early skeletal stability.

Abstract

Abstract Postoperative skeletal stability issues are frequently attributed to the tension exerted by the pterygomasseteric muscle sling following mandibular setback. This study investigated the hypothesis that simultaneous mandibular angle resection during Bilateral Sagittal Split Ramus Osteotomy (BSSRO) enhances skeletal stability by reducing this muscular tension. A prospective randomised controlled study was conducted on 20 patients with Skeletal Class III malocclusion - characterised by mandibular prognathism. The study sample was equally divided into an experimental group (4 males, 6 females; mean age 23.6 ± 3.9 years) undergoing the combined procedure (BSSRO with simultaneous mandibular angle ostectomy), and a control group (5 males, 5 females; mean age 20.4 ± 3.4 years) receiving isolated ramus osteotomy (conventional BSSRO setback only). Lateral cephalometric tracings were utilised to quantify the horizontal and vertical positional changes of the mental region, specifically at Point B, Pogonion and Menton, during the 3-month postsurgical healing phase. The results indicated a significant divergence in remodelling between the two groups. The control group characterised anterior relapse (B: +1.35 ± 1.50 mm; Pog: +0.81 ± 2.92 mm), whereas the experimental group demonstrated a stabilising posterior settling effect (Point B: -1.44 ± 1.93 mm; Pog: -1.14 ± 4.06 mm). These findings substantiate that resecting the mandibular angle effectively shortens the pterygomasseteric sling, thereby alleviating the muscular tension responsible for skeletal rebound. Consequently, simultaneous angle ostectomy during Surgery-First Orthognathic Approach (SFOA) mandibular setback protocol is advocated not merely as an aesthetic contouring procedure for lower facial width reduction, but as a functional release of the pterygomasseteric sling that significantly improves early skeletal stability, suggesting a larger study with Class II malocclusions as well or other types of skeletal deformity

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Cite This Study

Hung et al. (Fri,) studied this question.

synapsesocial.com/papers/6a13e7a80e02ee3982d325bd https://doi.org/https://doi.org/10.1016/j.jpra.2026.05.035

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