[The respective roles of occlusal abrasion and bacterial plaque in the etiology of alveolar lysis in periodontitis in hamsters].

This study was designed to determine the respective roles of occlusal attrition and subsequent tooth egression, and bacterial plaque accumulation on bone loss (or radicular denudation) during hamster periodontitis. Seventy young male animals were separated into 7 groups. Occlusal attrition was compared on 3 different diets (standard in pellet form, standard in powder form, and Keyes 2000 in powder form), thought to have different abrasiveness. The role of bacterial plaque wad evidenced by inhibiting it with Penicillin V in animals fed the same 3 diets. Compared to animals killed at the beginning of the experimental period (absolute controls), 3 months later bacterial plaque was slightly increased in hamsters fed the standard diet, very markedly increased in 2000 diet-fed animals and, decreased in the 3 antibiotic treated groups. Occlusal attrition was increased in the 2 groups fed the standard diets but not in the 2000 diet-fed animals. Radicular denudation was slightly increased in the standard diet groups, very markedly increased in the 2000 diet group, and unchanged in the antibiotic treated animals. Thus, the less abrasive diet was associated with the greatest plaque accumulation and bone loss; conversely, with the most abrasive diets, radicular denudation had slightly progressed with only small amounts of plaque. This suggests that in hamster periodontitis, bone loss is not influenced by occlusal attrition but is completely dependent on the direct action of bacterial plaque.