A method to enhance determining the clinical relevance of periodontal research data: number needed to treat (NNT).

It would be advantageous if clinical trials reported both statistical and clinically meaningful results. In this regard, determination of the number of sites that would need to be treated in a test group to provide a beneficial result or prevent an adverse event at one additional site beyond the control group would provide useful information. This editorial addresses the use of NNT (number needed to treat) calculations to enhance determining the clinical relevance of periodontal research findings. The application, requirements for use, benefits, and limitations of employing NNT calculations are discussed.