The bristles

are a major design element. Most people in the survey choose them as one of the most important features.

Weight Analysis

This is important to measure how much material is being wasted. the heaviest weighed 45 grams the lightest 14grams.

I studied old toothbrushes

and found that people brush too hard, and in this case should replace their brush sooner.

my toothbrush wastes very little material

the weight is only 12.92 grams

Solidworks process

The solid works process was easy, because my design had so many constraints, here is my initial concept.

prop for surveys

This is the board I used for my surveys, started with 15 toothbrushes, narrowed it down to 10.

dissection

this is one of the toothbrush I cut in half, learning allot from the dissection

Toothbrush survey Data Visualizations of Least Favorite Toothbrush

This clearly shows the least favorite toothbrush and gives an interactive interface to look at comments.
http://www-958.ibm.com/software/data/cognos/manyeyes/visualizations/least-favorite-toothbrush-and-note

pretty cool.