Animal model for disk displacement.

Area of Science:

• Temporomandibular joint (TMJ) disorders
• Animal models in research
• Soft-tissue biomechanics

Background:

• Nonreducing disk displacement is a common temporomandibular joint (TMJ) disorder.
• Understanding the progression of TMJ disk displacement is crucial for effective treatment.
• Previous studies have explored TMJ disorders, but a robust animal model for nonreducing disk displacement is needed.

Purpose of the Study:

• To describe the soft-tissue changes in the temporomandibular joint (TMJ) following surgically created, nonreducing disk displacement in a New Zealand white rabbit model.
• To evaluate the TMJ disk's structural integrity and associated tissue reactions over time.
• To establish a reliable animal model for studying the pathogenesis of TMJ disk displacement.

Main Methods:

• Surgical creation of nonreducing disk displacement in the temporomandibular joints of three New Zealand white rabbits.
• One control rabbit with an intact TMJ disk.
• Histological and gross morphological examination of TMJ tissues at immediate and 2-month post-surgery intervals.

Main Results:

• The control TMJ disk exhibited normal morphology with distinct anterior and posterior bands and an intermediate zone.
• Immediate post-surgery, the displaced disk showed buckling at the intermediate zone, with the posterior band inferior to the anterior band.
• Two months after surgery, TMJ disks displayed gross deformation and abnormal internal architecture, indicating significant remodeling and degeneration.

Conclusions:

• Surgically induced nonreducing disk displacement in rabbits leads to progressive disk deformation and abnormal internal architecture.
• Observed tissue reactions, including disk remodeling and degenerative changes, resemble those in human TMJ disk displacement.
• This rabbit model effectively simulates key aspects of human TMJ disk displacement, offering a valuable tool for future research into disease progression.