Effect of traumatic occlusion on periapical lesions in rats.

The effect of traumatic occlusion on periapical lesions in rats was investigated histologically and histometrically. Rats were divided equally into groups A to D. Rats in group A received no treatment; in group B, rats received pulpal exposure of the left mandibular first molar; in group C, a resin plate was cemented onto the occlusal surface of the corresponding maxillary molar; and in group D, the molar pulp was exposed and the resin plate was installed. At 1 and 2 wk, compression of the periodontal ligament and inflammation were less in group D than in group B. Lesions in the periapical periodontal ligament at 1, 2, and 4 wk in group D were significantly smaller than those in group B. This study suggests that traumatic occlusion delayed the enlargement of the periapical lesions in rats.