Abstract: Improvements to a manually operated, rotary bristle toothbrush. A thumb actuated mechanism is slidably and longitudinally mounted in an essentially hollow, elongate handle and a part of the mechanism, a rack, is caused to engage at least one compound pinion/spur gear in order to convert longitudinally reciprocative motion to rotary motion that is shunted toward the head of the toothbrush. The head contains therein one or more rotary bristles that project orthogonally from the head of the toothbrush and off the major longitudinal axis of the device. Rotary motion is conducted by a drive shaft into the head of the brush and transferred via a crown gear to bases of the brush(es) by interface between the crown gear of the drive shaft and at least one brush base comprising a capstan device adapted for rotation.