Black & white drawing
Left - Straight lines representing taut strands of dental floss placed at various angles to show that the concave surfaces cannot possibly be reached effectively by the floss in cleansing. Right - Cleansing action of bristles in similar approximal concavities made possible by the leverage of the bristles through the circular stroke of the brushhead. [...]. The necessity of adequate length of bristles for intraproximal brushing is here apparent.
This work is dedicated to the Public Domain.