Actual electric toothbrushes or power toothbrushes are equipped with a recharging base that plugs into a wall outlet, allowing for the continual recharging of your toothbrush. As with manual toothbrushes, it is recommended to replace the soft-bristled heads every three to four months, to ensure optimal cleaning results. Some electric toothbrushes are made with special features, including gum massage and whitening, as well bristles for sensitive teeth. Some are even affixed with sensors that monitor the pressure you are applying to your teeth and gums and will shut the electric toothbrush off to prevent damage to the delicate areas of your teeth and gums. In addition to these special features, you can even purchase brush heads that have specific qualities, such as, oscillation, rotation, and sonic technology.