Comparison of different methods of temporomandibular joint disc reconstruction - An animal model

The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included. Article first published online: 12 MAR 2008The optimum method of temporomandibular joint (TMJ) reconstruction has not been defined despite numerous surgical treatments and several well controlled clinical trials. Animal models offer an experimental method allowing direct comparison of standardized surgical techniques. Advanced osteoarthrosis was induced bilaterally in 12 mature merino sheep. Three months later unilateral surgical reconstruction was performed. Four sheep had discectomy alone, four discectomy with fresh TMJ disc grafts, and four discectomy with fresh auricular grafts. All three surgical methods resulted in some reversal and repair of the osteoarthritic process, with the best result being from the auricular graft, next discectomy alone, next the disc graft, with the untreated osteoarthritic joint showing the most advanced pathosis. This study supports the role of surgical reconstruction in advanced degenerative disease of the temporomandibular joint, in particular, auricular graft reconstruction.Nobumi Ogi, Jun-Ichi Ishimaru, Kenichi Kurita, Yujiro Handa, Robert H.B. Jones, Alastair N. Gos

The effect of hyaluronic acid on experimental temporamandibular joint osteoarthrosis in the sheep

PurposeThe purpose of this study was to test the effect of repeated injections of hyaluronic acid (HA) on the sheep model of osteoarthrotic temporomandibular joint (TMJ) disease.Materials and methodsBilateral osteoarthrosis (OA) was induced in the TMJs of six sheep. HA was injected into one joint on 7, 10, 14, 17, and 21 days postoperatively. Normal saline was injected into the contralateral joint. Three sheep were killed at 1 month and 3 at 3 months. The joints were removed and examined macroscopically and histologically. A special scoring system was applied following the modified Mankin's score to evaluate the histologic changes.ResultsThe control group showed severe osteoarthrotic changes in the condyle, deviation in form from normal morphology, and marked marrow fibrosis. The HA-treated group showed less deviation from normal condylar morphology. The histologic scores at 1 month were HA 12.6, control 24.2 (P ConclusionRepeated intraarticular injections of HA into a sheep TMJ with experimentally induced OA minimizes the extent of osteoarthrotic change when compared with the control joint. Thus, HA may have a role in preventing the progression of TMJ OA.Hisashi Neo, Jun-Ichi Ishimaru, Kenichi Kurita, Alastair N Gos

Effect of unilateral condylectomy on the sheep temporomandibular joint

Unilateral condylectomy was performed on five young adult sheep. The animals were killed at three months and both joints and the excised condyles were examined macroscopically and histologically. All five showed pronounced regeneration of the condylar head on the operated side. The articular surface was fibrous and fused to the disc. Four of the five opposite joints showed medial remodelling. Young sheep have a higher regenerative capability than human adults of equivalent age, and similar reactions to those of children