Experimental gingivitis in relation to susceptibility to XXXX . II. Phase-contrast microbiological features and some host-response observations.

@entity1 @entity32 @entity2520 @entity548
In the present investigation, a number of histological and immunohistochemical characteristics of periodontal tissues as well as the phase-contrast microscopy of dental plaque were studied after experimentally-induced @entity32 in relation to susceptibility to @entity2520 . The study included a younger (mean age 34.1 years) and an older age group (mean age 48 years) with a reduced but healthy periodontium. Both age groups had the same amount of loss of attachment which may suggest that they had different degrees of susceptibility to @entity2520 . At the start of the experiment, each @entity1 was instructed to abstain from oral hygiene in one quadrant of the mouth for a period of 18 days. At the end of the 18-day period, supra-gingival plaque and gingival tissue samples were taken. As determined by phase-contrast microscopy, the plaque samples of both age groups contained relatively high proportions of spirochetes. This may indicate that the @entity1 are at risk for recurrence of periodontal breakdown. The general histopathologic picture of the gingival tissue samples of both age groups was similar to the so-called 'early lesion'. However, IgA-producing plasma cells were found in most tissue samples of both age groups. The first part of this study showed that the younger, in comparison to the older, @entity1 developed @entity32 in terms of @entity548 on probing more rapidly. These clinical results cannot be explained by the host-parasite parameters investigated in the present study.
