Microflora in oral ecosystems in subjects with radiation-induced hyposalivation

To analyse the microbial flora in specific oral sites in 13 dentate subjects, 6-8 months after completed radiation therapy (RT group) and in 13 matched controls.

The microflora on the tongue, buccal mucosa, vestibulum, supragingival plaque and subgingival region was analysed using duplicate sampling and cultivation technique. A clinical examination was also performed.

Candida albicans was found in one or more sites in 54% of the RT subjects and in 15% of the controls. In three RT subjects, C. albicans was found at all four sites analysed. An unexpected finding was that enterococci were found in all RT subjects and in high number in 38%. None of the controls harboured enterococci. In supragingival plaque, Lactobacillus spp. were detected in 92% of the RT subjects and the number and proportion of Lactobacillus spp. were extremely high compared with the controls. Mutans streptococci were detected in high numbers in 31% of the RT subjects, while they were not detected in 23%.

The microbial results explain why some RT subjects have an increased susceptibility to oral diseases and stress that site-specific microbial analysis is an important diagnostic tool when planning oral health preventive care for RT subjects.