Subgingival plaque and loss of attachment in periodontosis as observed in autopsy material.

Histologic sections from six autopsy cases which from a clinical point of view fitted into the criteria of periodontosis were examined with the aim at evaluating the role of subgingival plaque in the etiology of the loss of attachment in this condition. The following pertinent observations were made: 1. The subgingival plaque in most instances was not calcified to form calculus. 2. The thickness of the subgingival plaque varied between 20 and 200 mu (0.02-0.2 mm). 3. Where loss of attachment had taken place, the distance from the most apical part of the subgingival plaque to the most apical point of the epithelial cuff varied between 0.2 and 1.1 mm; this distance was never found to be more than 1.1 mm. This would indicate a cause and effect relationship, the plaque being the obvious cause. 4. There was very severe chronic inflammation in the soft tissue bordering upon the plaque with resulting collagenolysis. 5. The cellular infiltration and the collagenolysis may be limited to a zone of 1 to 2 mm in the immediate vicinity of the plaque. Between the inflamed area and the surface of the gingivae buccally and lingually there may be a fairly wide zone of healthy tissue which hides the symptoms of inflammation from being observed on a clinical examination. In turn this could leave the clinician with the impression that attachment has been lost and bone resorbed because of degenerative changes. The following conclusions can be made: In these six cases of "alveolar bone loss vastly out of proportion to what one would expect from the local etiologic factors in the patient at that age" there was no morphologic evidence that degenerative changes were responsible for the loss of attachment. On the contrary inflammatory changes induced by the subgingval plaque dominated the histopathologic picture.