ABSTRACT
<p><b>OBJECTIVE</b>To observe the post-injury regenerating ability of temporomandibular joint of rats exposed to the repeated + Gz forces.</p><p><b>METHODS</b>One hundred and eight male rats were randomly assigned to 9 groups, with 12 rats in each group. Group A was normally fed serving as the blank control group. Group B was only fixed with rat-kept devices for 5 minutes as the fixed control group. Group C was borne +1 Gz for 5 minutes. In the same position as group C, group D, E, F, G, H and I were repeatedly exposed to +10 Gz for 30 seconds each time with 5 times a day and +1 Gz for 1 minutes as a interval. The 6 groups were treated in the condition above for 4 days a week and 4 weeks in total. The rats in group A, B, C and D were killed on the next day after the centrifuge. The rats in group E, F, G, H and I were killed at 1, 2, 4, 8 and 12 weeks after the centrifuge, respectively. After the rats were killed, temporomandibular joint were taken for observation under optical microscope, scanning electron-microscope (SEM) and transmission electron-microscope (TEM).</p><p><b>RESULTS</b>There was no significant difference observed in group A, B and C. But in group D, E, F, G, H and I pathologic injuries and self-regeneration were seen in TMJ in different degrees.</p><p><b>CONCLUSIONS</b>The injury of TMJ could regenerate gradually with time.</p>