Effect of periodontal trauma upon intrabony pockets.

Conflicting results have been reported regarding the effect of periodontal trauma upon progression of periodontitis. In these studies, different initial pocket morphologies were present. This study investigated the effect of trauma superimposed upon existing intrabony pockets. Localized intrabony pockets were produced adjacent to the mesial and distal surfaces of the mandibular third bicuspids in 10 squirrel monkeys. Two animals were killed after 10 weeks of periodontitis. In four (experimental) of the remaining eight animals, mesio-distal jiggling of the third bicuspid was begun 10 weeks after induction of periodontitis, and continued for another 10 weeks. The other four animals (control) were killed 20 weeks after initiation of periodontitis. Step-serial histologic sections were selected from experimental and control specimens and analyzed for loss of connective tissue attachment, loss of crestal alveolar bone and percentage of bone in the coronal interproximal periodontium. When corresponding dimensions from experimental and control surfaces were compared statistically, there were no differences in loss of connective tissue attachment but a greater loss of bone had occurred in specimens with the combination of periodontitis and trauma. In addition, there was a marked difference in osseous morphology between the experimental and control specimens. It was concluded that trauma superimposed upon existing intrabony pockets increased loss of alveolar bone and altered osseous morphology, but did not affect the loss of connective tissue attachment.