Stomatology ›› 2026, Vol. 46 ›› Issue (4): 289-294.doi: 10.13591/j.cnki.kqyx.2026.04.009

• Basic and Clinical Research • Previous Articles     Next Articles

MRI analysis of preoperative and postoperative changes of masticatory muscle morphology in unilateral anterior disc displacement of temporomandibular joint

ZHAO Zhuangzhuang1,2,3, ZHANG Ping1,2,3, JIANG Hongbing1,2,3, YAN Enshi2,3,4(), XU Rongyao1,2,3()   

  1. Department of Oral and Maxillofacial Surgery, the Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing 210029, China
  • Received:2025-11-06 Online:2026-04-28 Published:2026-04-17
  • Contact: YAN Enshi, XU Rongyao E-mail:17702507131@163.com;rongyaoxu@njmu.edu.cn

Abstract:

Objective To analyze the morphological changes of masticatory muscles (medial pterygoid, lateral pterygoid, and masseter) before and after unilateral temporomandibular joint disc repositioning surgery, and to identify effective evaluation indicators, thereby providing a more comprehensive basis for assessing surgical efficacy. Methods A retrospective analysis was performed on MRI data from 94 patients with unilateral anterior disc displacement between January 2022 and December 2023, including those with disc displacement without reduction (ADDwoR, n=78) and with reduction (ADDwR, n=16). Morphological parameters of the bilateral medial pterygoid muscle, superior/inferior heads of the lateral pterygoid muscle, and masseter muscle were measured. Masticatory changes before and after surgery were analyzed in ADDwoR patients. Results In ADDwoR patients, the affected-side/healthy-side volume ratio of the masseter muscle was 0.79. In ADDwR patients, the masseter volume ratio was 0.91. Postoperatively, the masseter volume ratio in ADDwoR patients increased to 1.00, with morphology tending to approximate the healthy side. Conclusion Unilateral ADDwoR is manifested with significant masseter atrophy. Postoperative masseter symmetry improves but does not fully recover. Changes in masseter symmetry before and after surgery can serve as an important indicator for evaluating surgical efficacy and reflecting functional and aesthetic improvements in the maxillofacial muscle groups.

Key words: temporomandibular joint disorders, anterior disc displacement, masticatory muscles, magnetic resonance imaging, disc repositioning surgery

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