Abstract:

Objective

To establish repeatable animal models of increasing occlusal vertical dimension （iOVD） in adult rats； to evaluate the influence of iOVD on nutrition intake，periodontal tissue and temporomandibular joints.

Methods

60 adult Wistar rats were randomly divided into two groups， the control group and iOVD group. The rats in iOVD group wore maxillary bilateral posterior dentition splints and those in the control group remained nature. With prosthodontic techniques， the resin splints of iOVD were made and bonded. The rats were sacrificed in 3 d，1 w，2 w，3 w，4 w after the experiment. Weight analysis， lateral head radiography， specimen anatomy and histological sections of tooth and temporomandibular joint（TMJ） were performed and results were evaluated.

Results

The weight curves for rats in the control and iOVD groups were basically uniform and the results of variance analysis showed no statistical difference after repetitive measurements. In the rats of iOVD group occlusal deviation，unilateral masseter swelling and asymmetry dentition abrasion didn't occur. However， pathological changes and remodeling in periodontal tissue and temporomandibular joint were observed.Radiographs demonstrated that condyles moved forward and downward. The incisors gradually wore and erupted to compensate the increased OVD at 2 ～4 w.

Conclusions

The animal models of iOVD adult rats can be successfully established with prosthodontics techniques. The wear of occlusal splints induce the changes on periodontium and TMJ cartilage of adult rats.However， nutrition intake is unaffected.

Key words: Animal model, Ccclusal vertical dimension, Rats, Condylar, Histological