Significant improvement in the dental caries status of children in the United States has been seen in recent decades. The percentage of children who are free from dental caries, however, rapidly decreases with age. By the time young people enter colleges or universities, only a few are caries free. Colleges and universities are places where the young are simultaneously, and perhaps for the last time, reachable as large cohorts before their lives undergo further "individualization." This makes college age a time that is crucial for channeling information about proper oral health practices by organizing mass-directed strategies for prevention of dental caries. It is now clear that dental caries can effectively be prevented. This calls for placing strong emphasis on dietary behavior and on the use of sugar substitutes as part of the strategy. Scientific evidence also suggests that the addition of small daily quantities of xylitol, a natural carbohydrate sweetener, to the diet of children and young adults causes significant reduction in the incidence of dental caries. On the basis of detailed long-term clinical trials carried out during the past 20 years, it appears that a reduction ranging from 30% to more than 85% in dental caries can be achieved simply by using a few xylitol chewing gums daily over a period of 1 to 3 years. In individual cases, virtually total, long-term protection against caries has been observed.(ABSTRACT TRUNCATED AT 250 WORDS)