An Animal Model for Inducing Anterior Disc Displacement of the Temporomandibular Joint

Aims: To develop an animal model of anterior disc displacement (ADD) without the need for opening the temporomandibular joint (TMJ) capsule. Methods: Thirty-two healthy adult Japanese white rabbits were used in this study. Four rabbits were dissected to familiarize the investigators with the anatomy of the TMJ. Sixteen animals were subjected to surgical ADD in the right TMJ, 8 animals had a sham operation, and 4 animals were not operated (normal controls). Four rabbits from the experimental ADD group and 2 from the sham group were sacrificed 1, 2, 4, and 8 weeks, respectively. The rabbits in normal control group were sacrificed at the beginning of the experiment. Animal behaviors as well as macro- and microchanges in the TMJs were investigated. Results: Fifteen right TMJ discs in the 16 experimental rabbits were successfully displaced anteriorly, and the degree of ADD in the experimental group was similar. The mandible of each ADD rabbit deviated to the left side with inclined attrition of the incisors. Some histologic changes appeared in the experimental TMJs. Conclusion: This ADD technique without the need for opening the TMJ capsule is effective, and the model is suitable for studying ADD of the TMJ. Keywords: animal model, anterior disc displacement, rabbits, temporomandibular joint