Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA.
The J.D. Wheat Veterinary Orthopedic Research Laboratory, School of Veterinary Medicine, University of California-Davis, Davis, CA.
Am J Vet Res. 2024 Apr 22;85(7). doi: 10.2460/ajvr.24.01.0009. Print 2024 Jul 1.
To evaluate the kinematics and stability of the temporomandibular joint (TMJ) of cats and dogs with and without a TMJ replacement (TMJR) prosthesis under simulated bite forces and mouth opening.
Sixteen cadaver skulls from domestic cats (n = 8) and medium- to large-breed dogs (n = 8).
Intact TMJs were tested. Following condylectomy and coronoidectomy, the skulls were fitted with a TMJR prosthesis unilaterally and retested. Prosthesis was similarly implanted in the contralateral TMJ in 4 cats and 4 dogs before retesting. Left and right bite motions were evaluated before bite contact to peak bite force (200 N in dogs, 63 N in cats). Mouth opening motion was recorded. Mandibular displacement under load was evaluated in 3 orthogonal planes. Maximal displacement was compared between TMJR groups and native TMJ. Prosthesis-bone motion of the temporal and mandibular components was evaluated during simulated bites and mouth opening.
TMJR resulted in joint motion not demonstrably different from the native TMJ, with the ability to fully open and close the mouth and with minimal laterotrusion. The TMJR prosthesis demonstrated similar stability after unilateral and bilateral replacement during bite force and with an open mouth. Mean implant-bone motion during bite simulations for the temporal and mandibular TMJR components was ≤ 60 µm in cats and ≤ 30 µm in dogs.
A novel TMJR can be implanted and allows normal jaw motion. Joint stability is maintained after TMJR implantation in the TMJ of dogs and cats TMJ that is devoid of muscular support.
评估猫和狗的颞下颌关节（TMJ）在模拟咬合力和张口时有无 TMJ 置换（TMJR）假体的运动学和稳定性。
16 个来自家养猫（n = 8）和中等到大型犬（n = 8）的尸体头颅。
测试完整的 TMJ。行髁突切除术和喙突切除术，单侧安装 TMJR 假体并进行再次测试。4 只猫和 4 只狗在再次测试前，将假体同样植入对侧 TMJ。在咬合接触前评估左右侧咬合运动至最大咬合力（犬 200 N，猫 63 N）。记录张口运动。在 3 个正交平面评估加载下的下颌骨位移。比较 TMJR 组与原生 TMJ 的最大位移。评估颞骨和下颌骨组件在模拟咬合和张口时的假体-骨运动。
TMJR 导致的关节运动与原生 TMJ 无明显差异，能够完全开闭口腔，且侧向旋转度最小。单侧和双侧置换后，TMJR 假体在咬合力和张口时具有相似的稳定性。猫和狗 TMJR 假体在模拟咬合期间的颞骨和下颌骨组件的平均植入-骨运动≤60 µm 和≤30 µm。
新型 TMJR 可植入并允许正常下颌运动。在无肌肉支持的犬和猫 TMJ 中，TMJR 植入后关节稳定性得以维持。
