Powered toothbrush systems that provide improved bristle positioning and bristle contact with tooth surfaces that reduce the time and effort required for effective brushing. Some embodiments use alternating or oscillating pneumatic pressure and suction to move a toothbrush head. Various configuration of the brush head provide different areas of coverage ranging from individual tooth to quarter mouth (U-cross section), to half (U-cross section or H-cross section) or whole mouth (U-cross section or H-cross section) coverage. Some embodiments include flexible fingers and/or bladders to keep the bristle tips properly engaged with the teeth and gums, providing bristle contact over a wide variety of malocclusion. The shape of the brush heads adapts to conform closely to the shape of the user's dental tray and to any malocclusion that may be present. The powered toothbrush automatically generates motion of the brush head that simulates the Modified Bass Method of brushing.