The purpose of this study was to evaluate whether the use of a Sonicare toothbrush could be beneficial in reducing coronal and/or root caries among patients with medication-induced xerostomia. Eighty subjects with drug-induced xerostomia using either a Sonicare toothbrush (SC) or a manual toothbrush (MTB) were included in the study. Control subjects using a MTB were frequency-matched to 40 subjects using a SC, based on age, gender, number of teeth at baseline, and salivary flow rates. Subjects were individually matched according to the type of xerostomic medication they were taking. Caries were assessed at baseline, and subjects were instructed to have carious teeth restored. Summary statistics were assessed and computed by treatment group for incipient and frank coronal and root caries after one year. Statistical comparisons of the number of frank and incipient coronal and root caries between treatment groups were conducted using paired t-tests. After one year of use, the numbers of incipient and frank root caries were significantly lower among subjects using SC compared to subjects using MTB. Subjects using SC also exhibited somewhat lower incipient and frank coronal caries than subjects using MTB, although their differences were not statistically significant. The authors concluded that the Sonicare toothbrush may be beneficial in reducing root caries among older adults with medication-induced xerostomia.