Types of clinical caries studies: epidemiological surveys, randomized clinical trials, and demonstration programs.

This has been a necessarily cursory overview of three types of clinical dental caries studies: the dental survey, the randomized clinical trial, and the non-randomized comparative study. Each of these studies may be used in its appropriate place, although only the survey and the randomized clinical trial are well-grounded in scientific theory. In general, the dental survey is well-suited to gathering basic cross-sectional data on dental caries, data that serve a variety of important practical and scientific interests in the dental care system. Clinical trials and non-randomized studies are applied in evaluating a variety of therapies for dental caries. Of the two, the randomized clinical trial is by far the more powerful. As a result, the clinical trial has found a central place in dentistry. The contributions that past and present clinical caries trials have made to dental health are quite evident to most observers. It is virtually inescapable that well-conducted clinical caries trials will make even more significant contributions to dental practice in the future, thereby further improving the oral health of all.