The intervals the comparisons assume

Two minutes, twice a day, with a fluoride toothpaste, and a new head about every three months. That is the ADA-shaped baseline these pages use when they turn a head price into a yearly cost. A quadrant pacer exists so the two minutes are not all spent on the same three teeth.

Floss or a water flosser is still a separate job unless the brush is a Sonic-Fusion or a CameraJet, and even those are not a reason to skip a dental cleaning. Bleeding gums after a careful week belong in a chair, not in a whitening mode.

Source for the interval, not for a product rank: ADA toothbrushes.