[Bacteriological characterization of gingivitis-inducing plaque depending on different sugar levels of the diet].

In a time period of 21 days an experimental gingivitis was induced in 8 volunteers. Four volunteers received a carbohydrate-reduced, the other 4 persons a carbohydrate-enriched diet. Clinical investigations on the development of plaque and gingivitis and bacteriological examinations of the supragingival microflora were performed simultaneously. The change in the composition of the supragingival plaque-microflora were nearly independent of the amount of food-carbohydrate. In the beginning of the experiment all volunteers had an almost pure streptococcal microflora but during the course of the experiment, the supragingival flora developed to a complex microflora with 50% anaerobes. The reduction of the number of streptococci was accompanied by an increase in the number of Gram-negative rods and actinomycetes. The development of gingivitis in persons with carbohydrate-enriched food was more rapid than in persons with carbohydrate-reduced food. It was striking that the occurrence of clinical symptoms correlated with the increase of the number of Actinomyces viscosus in the plaque material.