Conflicts of interest.

Conflicts of interest are unavoidable in dentistry. A set of five questions is offered to help sort through such conflicts. The potential harm and the likelihood of such harm caused by secondary interests (the potentially conflicting ones) must be considered against the potential harm and the likelihood of damage caused by withholding services in which secondary interests are present. The use of these questions is illustrated with an example of a researcher who has a commercial interest in the product under study and of dentists who have secondary interests in services provided to patients.