Objectives: This study aims to: a) quantify the incidence of preventive dental services [n-office fluoride application and dental cleaning (prophylaxis)]; b) determine if these services are effectively targeted to patients with the highest need; and c) quantify the role of practice characteristics and patient-level factors in service receipt. Methods: A population-based prospective cohort study was conducted with 873 adults who had at least one tooth at baseline, 743 of whom provided 48-month data. In-person interviews and clinical examinations were conducted biennially for 48 months, with 6-monthly telephone interviews in between. Dental records were abstracted afterward, and practices that served participants completed questionnaires. Analysis was limited to persons with at least one dental visit of any type during follow-up (87 percent of the sample). Results: Only 9 percent of the persons received at least one fluoride application; 75 percent received a dental cleaning. Persons with high need were actually less likely to have received preventive services. In multivariable regression analyses, characteristics of the practice in which the subject received care were very strongly related to fluoride receipt, independent of patient-specific characteristics. Conclusions: One preventive procedure was common; the other was uncommon. However, practices did not effectively target high-risk patients for either procedure. Instead, both services were typically received by persons with the least need for them. These findings are consistent with the conclusion that practitioners greatly influenced the delivery of fluoride services, with substantial contributions also made by patient-level predisposing and enabling factors for both preventive services. © 2008, American Association of Public Health Dentistry.