The development of an altered gingival crevicular microflora in the alloxan-diabetic rat

The microflora of the rat gingival crevice were examined at various time intervals after inducing experimental diabetes. A variety of Gram-positive and Gram-negative cocci and short rods were isolated from the normal rat crevice. Within a week after alloxan administration, Leptotrichia buccalis was detected for the first time. Other features in the diabetic animals included an increased frequency of isolation of Proteus spp., Lactobacillus spp. and decrease of Escherichia coli. Occasionally, a decrease was also observed in Bacteroides spp. and Streptococcus spp. No difference was observed between diabetic and non-diabetic animals in the isolation of Selonomonas, Campylobacter, Bifidobacterium and Actinomyces. Plaque accumulation was markedly increased in the diabetic rats. It was concluded that the change in gingival microflora resulted from diabetes-induced alterations in the sulcular environment (such as increased substrate levels, e.g. glucose and urea, and decreased oxygen) and that the microbiological changes preceded the depending of the periodontal pocket.