Although the first toothbrush is thought to have been used in about 1000 ad, tooth brushing in America did not gain popularity until after 1945. The introduction of the powered toothbrush in 1960 has led to a large number of studies comparing the safety and efficacy of powered toothbrushes to manual toothbrushes. There is a general agreement that powered toothbrushes are as safe as manual toothbrushes; however, studies show significantly differing conclusions regarding the efficacy of power toothbrushes for the removal of plaque. The recent amendment of the Cochrane report on this subject concluded that the only type of powered toothbrush that removes more plaque than a manual toothbrush is one with rotational oscillation movement. Their conclusion was based on the review of 29 published studies, conducted between 1964 and 2001, with a total of 2547 participants. All these studies used similar research design criteria. The Cochrane conclusion is in agreement with a 1996 study carried out in the Netherlands. Many of the conflicting study conclusions, to date, on powered toothbrushes, are the result of using differing study design criteria. While the dental profession desires evidence-based research, it is clear that dental schools will need to increase the level of attention in their curriculum to address disciplined techniques for research design in order to reconcile the large variances in reported research results.