Co-destructive factors of marginal periodontitis and repetitive mechanical injury.

When repetitive mechanical injury was produced in combination with marginal periodontitis a significant loss of connective tissue attachment did not occur as compared with specimens in which periodontitis alone was produced. It seems unlikely, therefore, that there is a "co-destructive" factor effect on the loss of connective tissue attachment. The amount of alveolar bone lost as a result of marginal periodontitis was increased by the addition of repeated mesiodistal jiggling of the teeth. This could represent an irreversible "co-destructive" effect or could merely be a functional adaptation of the periodontium.