Trauma and progression of marginal periodontitis in squirrel monkeys. I. Co-destructive factors of periodontitis and thermally-produced injury.

Abstract

This investigation was designed to test the co‐destructive factor hypothesis that a traumatic lesion subjacent to marginal periodontitis alters the progression of the periodontitis and produces angular bony defects. Marginal periodontitis was produced around 28 mandibular teeth in 7 squirrel monkeys by tying a silk ligature at the gingival margin to facilitate plaque accumulation. Six months after inducing periodontitis a severe traumatic lesion was produced subjacent to the marginal periodontitis in 15 of these teeth by thermal injury via the root canal. These specimens (Group I) were analyzed from 3 days to 6 months after injury subjacent to the periodontitis. The duration of periodontitis in the remaining 13 teeth (Group II) was the same as Group I allowing a comparison between the groups. It was concluded that the presence of a severe traumatic lesion and its sequelae subjacent to a marginal periodontitis did affect the progression of the periodontitis when evaluated by apical migration of the junctional epithelium and loss of alveolar bone. Angular bony defects occurred only when periodontitis was induced around isolated tooth surfaces and were related to the presence or absence of the traumatic lesion. Angular defects may be related more to location of etiologic agent than a combination of co‐destructive factors.