Pathological Effect of Lateral Pterygoid Muscle in Traumatic Temporomandibular Joint Bony Ankylosis

doi:10.13701/j.cnki.kqyxyj.2021.05.013

Abstract

Abstract: Objective: To verify the effect of lateral pterygoid muscle (LPM) in the pathogenesis of traumatic TMJ bone ankylosis. Methods: Animal model of TMJ bone ankylosis was established in 7 6-month-old male sheeps with bilateral TMJs simulating sagittal fracture of condyle and lateral 1/3 articular disc resection. Left TMJ was used as the experimental group to block the LPM function. Right TMJ was used as the control group to maintain the LPM function. All sheep were euthanized 12 weeks after surgery. All TMJ complexes were evaluated by gross anatomy, helical-CT, micro-CT, and histopathological examination. Results: Gross anatomy showed that the control TMJ complexes developed bone ankylosis, while the experimental TMJ complexes only developed fibrous adhesion. Helical-CT and micro-CT showed that, compared with the experimental group, calcification callus images were observed in the joint space of control TMJ complexes, and irregular calcification images of new bone were observed in the upper and lower articular surfaces. The maximum mediolateral and anteroposterior diameters of control condyles were significantly larger than those of experimental condyles. Micro-CT showed that there were significant differences with all microstructural parameters between two groups (P<0.05). In the control group, the main growth orientation of new trabecular bone in the condylar fracture area was consistent with the LPM contraction direction, but not in the experimental condylar fracture area. Histopathological examination revealed that fibro-osseous ankylosis occurred in the control TMJ complexes, but not in the experimental TMJ complexes. Conclusion: Effect (similar to distraction osteogenesis) of LPM was an important and pathological cause of traumatic TMJ bone ankylosis after the sagittal fracture of condyle

Key words: lateral pterygoid muscle, animal model, sagittal fracture of mandibular condyle, temporomandibular joint ankylosis, distraction osteogenesis

DENG Tiange, LIU Ping, LIU Changkui, ZHANG Linlin, WU Ligeng, ZHOU Hongzhi, DING Yuxiang, HU Kaijin. Pathological Effect of Lateral Pterygoid Muscle in Traumatic Temporomandibular Joint Bony Ankylosis[J]. Journal of Oral Science Research, 2021, 37(5): 442-447.

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