Study of root caries in an artificial mouth.

The object of this project was to develop a laboratory model system to study root and enamel caries. Model plaque biofilms containing consortia of four (Streptococcus mutans, Streptococcus sobrinus, Actinomyces naeslundii, and Lactobacillus rhamnosus) or six (S mutans, S sobrinus, S mitis, A naeslundii, L rhamnosus, and Veillonella dispar) species of caries pathogens were developed in a artificial mouth. Caries lesions similar to those found in vivo were produced on enamel and dentine blocks and in intact root tissues by these consortia more effectively than biofilms of the individual species. Fluoride supplied at 5 ppm suppressed enamel caries effectively, less so dentinal lesion formation, but much more so than F incorporated into the mineralised surface of enamel and roots. This is the first direct comparison of the effect on caries of environmental F and tooth mineral F induced by a plaque-like bacterial biofilm.