BACKGROUND: The emergence of health information technology provides an opportunity for health care providers to improve the quality and safety of dental care, particularly for patients with medically complex conditions. METHODS: The authors randomized each of 15 dental clinics (HealthPartners, Bloomington, Minn.) to one of three groups to evaluate the impact of two clinical decision support (CDS) approaches during an 18-month study period. In the first approach--provider activation through electronic dental records (EDRs)--a flashing alert was generated at the dental visit to identify patients with medically complex conditions and to direct the dental care provider to Web-based personalized care guidelines. In the second approach--patient activation through personal health records--a secure e-mail was generated or a letter was mailed to patients before dental visits encouraging them to ask their dental care provider to review the care guidelines specific to their medical conditions. RESULTS: The authors evaluated the rate of reviewing care guidelines among 102 providers. Participants in the provider and patient activation groups increased their use of the system during the first six months, which had a generalized effect of increasing use of the guidelines for all patients, even if they were not part of the study (P < .05). The study results showed that provider activation was more effective than was patient activation. However, providers did not sustain their high level of use of the system, and by the end of the study, the rate of use had returned to baseline levels despite participants' continued receipt of electronic alerts. CONCLUSIONS: The study results demonstrated that review of clinical care guidelines for patients with medically complex conditions can be improved with CDS systems that involve the use of electronic health records. CLINICAL IMPLICATIONS: As the U.S. population ages, dentists must be vigilant in adapting care for patients with medically complex conditions to ensure therapeutic safety and effectiveness. Expanded use of CDS via EDRs can help dental care providers achieve this objective.