A Study of Treatment on Temporomandibular Joint Osteoarthrisis Using Botulium in Rabbit

Objectives:To test the therapeutic efficacies of botulinum toxin on temporomandibular jiont osteoarthrosis(TMJOA) in rabbit Methods: 30 adult rabbits were used to establish animal models of TMJOA by collagenase injection method and divided into experimental and control groups.Each group was subdivided into control and experimental group, 5 rabbits served as normal control group. Botulismotoxin was injected into bilateral masseter muscles (MM) and temporalis muscles(TM) In experimental group. The MM and TM of control group were treated with physiological saline by the same means.At the end of 4,8,12 weeks ,Electromyography (EMG) of anterior temporalis (TA),posterior temporalis (TP) and MM of 5 samples in each group was recorded during postural position and clenching. The rabbit of control and experimental group were killed after EMG examination. Results: It shows that the EMG activity of MM, TA and TP of control group during postural position was significantly higher than that of normal group. But lower during maximal clenching. In experimental group EMG activity of MM, TA and TP during postural position and clenching was significantly lower than that of normal control group by the end 4,8 weeks. By the end of 12 weeks, the EMG activity in the two groups has no significantly difference. By the end of 4 weeks, samples of control group showed apparently OA changes, but that of experimental group showed slightly changes of OA. By the end of 8 weeks, OA change was more significantly in control group, but repair was found in experimental group. By the end of 12 weeks, samples of control group showed serious degenerative change, that of experimental group were close to normal construction. Conclusions:Masticatory muscle dysfunction was present during the development of TMJOA. Botulismotoxion can enhance the function of masticatory muscle and accelerate self-repairment of TMJ. It was proved to have significantly therapeutic efficacies on TMJOA.