Temporomandibular joint prosthesis for cats and dogs
UC Davis has patent pending status for its TMJ prothesis
The TMJR prothesis by the veterinary team at UC Davis. (Image courtesy of UC Davis)
Veterinarians from the UC Davis School of Veterinary Medicine have achieved patent pending status for an implant designed to replace the jaw joint in cats and dogs suffering from end-stage temporomandibular joint (TMJ) disorders.1 The initial research on the TMJ replacement (TMJR) prosthesis have been published in the American Journal of Veterinary Research,2 and results found that the prothesis allows for normal jaw motion and joint stability. This has the potential to transform the treatment of pets with dysfunctional TMJs, caused by either injury or illness.
“About 5 years ago, I suggested the need for a TMJ replacement because we were seeing increased number of cats and dogs with fused jaws,” said Boaz Arzi, DVM, DAVDC, DEVDC, FF-AVDC-OMFS, chief of the Dentistry and Oral Surgery Service (DOSS) at the UC Davis veterinary hospital, in a news release.1 “The only recourse we have for these animals is to remove all the affected structures in the jaws to enable opening the mouth. While this allows the patient to eat and drink, there is no longer functionality to the joint, and their mouth can never close properly again.”
Arzi worked on this project with Denis Marcelin-Little, DEDV, DACVS, DECVS, DACVSMR, a UC Davis veterinary orthopedic surgeon well versed in hip replacement and implant design and production, and Tanya Garcia, BS, MS, a biomedical engineer in the school’s J. D. Wheat Veterinary Orthopedic Research Laboratory. The 3 of them used the FDA approved TMJ prothesis for humans as a guideline, however Arzi stated that the one they were creating for pets only needed to move up and down and did not need to move side to side or back and forth like it does in humans.1
Once the team had a TMJR prothesis, the invention was tested on 16 total cadaver skulls consisting of 8 domestic cats and 8 medium- to large-breed dogs.2 The implant was tested with different bite forces and other functions to assess its performance and capabilities. The testing concluded that the UC Davis team’s TMJR was similar to the native TMJ in motion and function and therefore could be a viable replacement for patients.
The team is also currently testing the prothesis further with “load to failure” and “fatigue testing” to determine the maximum force that the joint can withstand and its longevity, respectively. “It was a good test of the implant’s feasibility. Putting our work in front of the world’s best experts in this field, and getting good feedback, was very encouraging for the future viability of this product,” Arzi stated.1
According to the UC Davis release, the TMJR implant is made up of a milled plate attached to the jawbone, with a neck and head that fit into a socket fixed to the skull. In beginning stages, it will come in 3 sizes (small, medium, large) to fit most dog and cat breeds, but custom-made implants might be an option later for pets with unique needs.1
DOSS will soon start selecting patients for the first trial of the TMJR implant, treating them on compassionate grounds before full clinical trials begin.
References
- Warren R. Patent pending on UC Davis-designed temporomandibular joint (TMJ) prosthesis for cats and dogs. News release. UC Davis School of Veterinary Medicine. April 19, 2024. Accessed May 9, 2024. https://www.vetmed.ucdavis.edu/news/patent-pending-uc-davis-designed-temporomandibular-joint-tmj-prosthesis-cats-and-dogs
- Arzi B, Weed M, Garcia TC, Goldschmidt SL, Marcellin-Little DJ. Kinematic performance of a novel temporomandibular joint replacement prosthesis under bite-force conditions in dogs and cats. Am J Vet Res. Published online April 22, 2024. doi:10.2460/ajvr.24.01.0009
