Microbial Profiles in Root Caries of the Elderly

Objectives: The purpose of the study was to determine the bacterial profiles of root caries in the elderly using microbial microarrays. Methods: Elderly subjects between 70-98 years old (36 females and 5 males) were selected. Plaque samples were collected from the sound roots of non-diseased controls (n=20). From diseased subjects (n=21)the following samples were analyzed: 1) plaque from one sound root, 2) plaque from one carious lesion, and 3) the underlying dentinal material from the same carious lesion. The Human Oral Microbe Identification Microarray (www.forsyth.org/homim) was used for the simultaneous detection of about 300 bacterial species, including not-yet-cultivated bacterial species. Results: A mean of 29 species/sample were detected in the control samples. Intact root surfaces in diseased subjects had a mean of 28 species/sample, but, as disease progressed, the bacterial profile was less diverse with 25 species/sample in carious lesions and 18 species/sample in dentinal samples. In the control subjects, Streptococcus mutans and lactobacilli were rarely detected and Actinomyces spp. were not detected. However, Actinomyces and lactobacilli were present in 50 % and 88 % of the diseased subjects, while S. mutans was only rarely detected. Conclusions: The bacterial profiles of root surfaces showed a wide diversity and were notably different in health and disease. Species of Actinomyces and Lactobacillus, and not S. mutans, appeared to be associated with root caries in the elderly.