Bacterial involvement in denture-induced stomatitis

Denture and mucosal plaque samples were collected from eight full-denture wearers of whom four suffered from denture-induced stomatitis (DIS). Cultures were made, and a proportional identification to species level was carried out of bacteria and yeasts. An inventory was made of the predominant flora. Results showed that the predominant microflora of both groups, both on dentures and the denture-bearing mucosa, consisted mainly of Gram-positive bacteria. Differences in the proportions of cocci were found between the predominant bacterial flora on the dentures. In the control group, 69% of the denture flora consisted of cocci, while on the dentures of the DIS group a mean of 33% cocci was found. Neither group of palates revealed any differences in the proportions of cocci. On these locations a mean of 69% was found. The plaque of dentures and the palates of the healthy group showed means of 35% and 31%, respectively, of obligate anaerobic bacteria, while in the DIS group these percentages were 56% and 43%, respectively. No obligately aerobic bacteria were found. Candida species was detected in both groups, both on dentures and palates in very low numbers (DIS group, median palates 0.02%, median dentures 0.25%). The predominant organisms were Streptococcus species, of which S. salivarius was mostly present on the palates of both groups. Other species which were regularly found at different locations were Veillonella parvula and species of Lactobacillus, Bacteroides, and Actinomyces.