Effects of antigen-induced arthritis and compressive mechanical stress on condylar head of mandible

Compressive mechanical stress was applied to the temporomandibular joints (TMJ) affected by antigen-induced arthritis to assess the etiological factors of idiopathic condylar resorption.

Following ovariectomy in 27 female rabbits, 12 received ovalbumin (OVA), 12 received phosphate-buffered saline, and three formed the control group. Each treated rabbit underwent an osteotomy, and a custom device was employed for one week postoperatively, with the length increased by 0.25 mm every 12 h to provide compressive mechanical stress to the TMJ. Thereafter, samples were obtained from the treated groups, subjected to histological staining and immunohistochemistry, and examined using micro-computed tomography.

At each examination, the OVA group showed a greater area and depth of bone resorption, with bone resorption continuing for three weeks following distraction. Additionally, subcondylar bone resorption was noted significantly earlier and had a greater prevalence in the OVA group and greater numbers of tartrate-resistant acid phosphatase-positive cells. Immunostaining for metalloproteinase (MMP)-3 and MMP-13 of the anterior condylar head in the OVA group after two and three weeks revealed high levels of both proteins from the surface to the deep cartilage layer.

Therefore, coexisting TMJ pathology factors, such as antigen-induced arthritis, promote a significantly greater amount of condylar head anterior surface bone resorption.