The purpose of the trial is to determine the extent to which daily use of xylitol lozenges reduces the appearance of new caries lesions in adults who tend to experience such lesions (i.e., caries-active adults).

Dental caries incidence is higher in adults than children. Recent recommendations from both the Centers for Disease Control and an NIH Consensus Development Conference on dental caries call for clinical trials of caries prevention methods in caries-active adults. Little is known about the effectiveness of caries prevention methods in adults, and virtually no information exists with respect to prevention among adults who are at elevated risk for developing caries lesions. This application describes a clinical trial of an intervention to prevent dental caries in caries-active adults that is responsive to the CDC and Consensus Conference recommendations.

The Xylitol for Adult Caries Trial (X-ACT) is a three-year, multi-center, randomized, placebo-controlled, double-blind study to determine the effectiveness of xylitol lozenges in reducing the incidence of coronal and root caries in caries-active adults. The intervention is the daily use of xylitol lozenges. Participants will be 750 adults (ages 25-75) with current or recent caries lesions who are dental school patients at one of three Clinical Centers in Chapel Hill, NC, Birmingham, AL, and San Antonio TX. These Clinical Centers offer diverse populations with substantial proportions of minority populations that enhance the generalizability of the findings. The Study Chair is located at the University of North Carolina-Chapel Hill, and the Data Coordinating Center is at the Kaiser Permanente Center for Health Research in Portland, OR.

This intervention is being tested because it represents a potentially effective caries prevention method with a high likelihood of adoption by dental practitioners as an "add on" caries preventive method for their caries-active patients. The potential for adoption of the intervention is an important consideration because current data suggest that caries-active adults are underexposed to caries-preventive treatment in dental practices. If effective, the intervention also holds potential as a public health measure.

Inclusion Criteria:

• age 25-80
• at least one caries lesion in year prior to enrollment
• at least 12 teeth without crowns
• no allergies to xylitol or aspartame
• anticipate remaining in area for 3 years

Exclusion Criteria:

• 10 or more caries lesions in year prior to enrollment
• currently receiving long-term antibiotic therapy
• history of head and neck radiation