Clinical trials on placement of implants in existing bone

The use of dental implants has become a predictable and frequently used treatment modality in partially and fully edentulous patients. In 1987, the United States Food and Drug Administration (FDA) classified dental implants as class III medical devices. In 1989, a proposed rule was published by the FDA calling for a Premarket Approval Application (PMA) for dental implants. A PMA requires the demonstration of safety and effectiveness through clinical trials. Although the effective date for Premarket Approvals and detailed information on study requirements have not been announced, many implant manufacturers have already initiated multi-center clinical trials. Despite these initiatives, several aspects regarding appropriate study designs, outcome criteria, and success or failure analysis still need clarification. Trials should be designed to minimize bias and variability. The cornerstone of the experimental design is set by the study objective. It will determine which of many possible clinical trial parameters are essential to enable the presentation of data to a regulatory body on which basis the safety and effectiveness of a device can be judged. With the multiplicity of patient characteristics, implant types, supported prostheses, study designs, evaluation parameters, and statistical analyses, it is a difficult task to design an optimal trial. It is the purpose of this paper to propose designs and components for implant clinical trials with various objectives.