Root surface caries and associated factors.

The prevalence of root surfaces caries in 208 randomly selected 55, 65, and 75-yr-old Swedes was related to the frequency of coronal caries, the number of remaining teeth and to bacteriologic, salivary, and dietary variables. At least one decayed or filled root surface was found in 89% of the individuals and all of those had also experienced coronal caries. The frequency of root surface caries was positively correlated to the frequency of coronal decay and negatively correlated to the number of remaining teeth and exposed root surfaces. The study shows that the same factors which are associated with enamel caries seem to be of importance in determining the development of root surface caries. The variation in the frequency of root surface caries was best explained by the salivary levels of mutans streptococci and lactobacilli, the percentage of surfaces harboring plaque and the frequency of carbohydrate intake. Other contributory factors were the saliva secretion rate and the buffer capacity.