Ethics – Human Case Study (2010) - Toothbrushes: Manual vs Electric.

Mon, 2012-02-27 10:59 -- pwhippey

Description of the Project

This project looked at the efficacy of a manual toothbrush versus a power toothbrush in the reduction of plaque. My hypothesis is that using an electrical toothbrush will reduce more plaque than a manual because it vibrates to get in to tough spots that are hard to reach with a manual. I divided 17 subjects into 2 groups. both groups followed exactly the same protocol, the only difference being, the toothbrush that they were assigned. I had 9 people brush with a manual brush and 8 with the power brush. The same dental professional measured their starting and ending plaque scores. My findings showed a very small difference in favour of the manual brush at a 64% reduction and the power at 62%. This did not support my hypothesis.

Advice or Ruling

This project involves the participation of humans, so that informed consent is required. Please consult this web site: for a description on how to do this.

The Ethics Committee has agreed that this investigation does not violate the ban on ingestion projects.

This project is approved for display at the Regional Science Fair and the Canada Wide Science Fair.

Your Project

If your proposed science fair project involves the participation of humans or the use of animals,
  1. Visit the Ethics web page so as to become familiar with the policies.
  2. Fill in the Request for Advice or a Ruling.
  3. Submit it to the Ethics Committee of your Regional Science Fair.


These case studies summarize interesting examples of science fair projects involving humans or animals submitted to the Youth Science Canada National Ethics Committee for review. A brief description of the proposed project is given, along with the ruling given by the Ethics Committee. Some details may have been changed in the descriptions so that the original source cannot be identified. The ethical challenges described have not been changed.