Method: 90 adult Wistar rats (15 weeks old, weighing 275±25g) were divided into five groups, 18 rats for every group. Then every group was divided into three subgroups, control, iOVD and OT groups, 6 rats for every subgroup. The rats in iOVD group wore maxillary bilateral posterior dentition splints, in OT group wore upper right occlusal trauma splints and in the control group didn't wear splints. With prosthodontics technique such as precise impression technique, bonding technique, the splints of iOVD and OT were made and bonded. The rats were killed in 3d,1w,2w,3w and 4w after wore the splints. Using routine HE-staining section, the histological changes of TMJ for the control, iOVD and OT groups were observed.
Results: 3d and 1w in the experiment, obvious inflammatory reaction appeared in the synovial membrane at the trauma side of OT group. The iOVD group showed slowly adaptive proliferation instead of the obvious early synovitis. The condylar cartilage of the rats in both iOVD and OT groups had pathological reaction and adaptive remodeling. The pathological change included edema and cluster hyperplasia of the chondrocytes, tangential crack of the surface, mucoid-like change of the cartilage matrix, etc. It was severe in OT group, especially in the side of Occlusal Trauma. But in iOVD group the adaptive remodeling was observed in both sides of condyle.
Conclusions: Trauma occlusion can experimentally induced the pathological change of synovial membrane and condylar cartilage, especially in the Occlusal Trauma side. Meanwhile, iOVD induced a moderate inflammation of synovial membrane and gradual adaptive remodeling of condylar cartilage in both side.