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This study was conducted in order to investigate the dynamics of the gingival inflammatory status during periods of plaque accumulation and thorough oral hygiene. After a period of prophylaxis, 42 volunteers were asked to abstain from aft oral hygiene measures for 2 weeks, whereafter oral hygiene was reinstituted. In the absence of oral hygiene, plaque was found at virtually all sites after 7 days and the number of sites with gingivitis increased simultaneously. A reduction in gingival inflammation occurred subsequent to plaque removal. During phases of both plaque accumulation and thorough oral hygiene, sites were found to convert from non-inflamed to inflamed status concurrently, as in the reverse direction. No association between plaque and gingivitis was revealed. The gingival status of a single site was a poor predictor of its status on the subsequent occasion. The proportion of inflamed sites convening to non-inflamed status was greater than the proportion of non-inflamed sites converting to inflamed status at any time. The estimated incidence rate remained fairly constant during both the plaque accumulation phase and the oral hygiene phase, whereas the estimated recovery rate was considerable lower during the plaque accumulation phase compared to oral hygiene phase. The clinical appearance is the outcome of the dynamics between these rates. The steady-state prevalences derived from the estimated "incidence" and "recovery" rates were quite similar to the actual findings after 14 d of plaque accumulation and the subsequent 10 d of thorough oral hygiene. [ABSTRACT FROM AUTHOR]

This study describes the histopathological features and the distribution of oral epithelial Langerhans cells in 19 gingival biopsies originating from an adult Tanzanian population characterized by very poor oral hygiene and severe gingival inflammation. Light-microscopically, all biopsies contained often large inflammatory connective tissue infiltrates, 6 of which predominantly contained plasma cells while the rest were dominated by lymphocytes. Seven specimens contained peculiar accumulations of round lymphoid and dendritic cells in the lower cell layers of the oral epithelium. These phenomena have not previously been demonstrated in human gingiva and deserve further attention in studies on the pathogenesis of periodontal diseases. Immuno-histochemical staining with OKT6, OKT4 and OKT8 antibodies showed markedly increased numbers of OKT6-positive cells in 7 specimens and clusters of OKT4- and OKT8-positive cells in the oral epithelium of 4 specimens. High numbers of OKT6-positive cells were not related to the presence of intra-epithelial, non-keratinocyte infiltrates or large connective tissue infiltrates. The variable numbers of oral epithelial Langerhans cells may therefore result from different bacterial antigens elucidating different responses or, alternatively, reflect different responses to similar plaque antigens penetrating the surface of the oral epithelium. [ABSTRACT FROM AUTHOR]

This study describes the cross-sectional findings on dental plaque, calculus, gingivitis, loss of attachment, periodontal pockets and tooth loss in a population of adult Tanzanians aged 30-69 years. In all age groups more than 90% of all tooth surfaces exhibited plaque and 50 65% exhibited calculus deposits. Both plaque and calculus deposits were more extensive in the older age groups whereas gingival bleeding affected 30-40% of the surfaces in all age groups. Less than 35% of all surfaces exhibited a loss of attachment ≥4 mm and less than 10% had a loss of attachment exceeding 6 mm. Loss of attachment was accompanied by recession of the marginal gingiva and pockets deeper than 3 mm were present on less than 10% of all surfaces. The mean number of teeth present ranged from 23.9 in the oldest to 29.5 in the youngest age group. An interesting finding was that relatively few individuals accounted for most of the loss of attachment and periodontal pockets found in the study. Therefore, in future epidemiologic studies marc emphasis should be put on the identification of these particularly susceptible subpopulations. [ABSTRACT FROM AUTHOR]