Statistical issues in assessing powered toothbrushes.

A symposium on powered toothbrushes was held at the 2000 IADR General Session. The author was asked to address statistical issues in conducting clinical studies. The objective was to cover important statistical topics that should be considered in scientific investigations, including designing the study, analyzing the results, and performing a critical scientific review. The American Dental Association (ADA) established guidelines during the 1990s. The author discusses these guidelines and addresses statistical issues they do not cover.