Three-year root caries increments: implications for clinical trials.

Seven hundred and ninety-six adult subjects (mean age, 39.9 years) received visual-tactile examinations for root caries over a three-year period. All subjects were employed or were the spouses of employees and resided in fluoride-deficient communities on Long Island, New York. During the three-year observation period, 81.4 percent of the subjects did not develop root caries. The 18.6 percent who developed root caries averaged 0.8 DFS/year. The subjects' ages and baseline root DFS status were associated with the development of a root DFS increment. The older the patient, especially aged 45 and older, the greater was the risk of developing root lesions or having root fillings placed. Subjects who had a root DFS score at baseline also were more likely to experience a root DFS increment. It is recommended that when designing clinical trials of agents purported to inhibit root caries, preselection criteria for the study population should consider the subjects' ages and past history of root lesions.