Many dentists recommend the use of powered brushes as they are the most efficient way of cleaning teeth. They give a thorough clean, help you to avoid applying too much pressure to your gums and tooth enamel, and if they have a timer built-in, they can guide you on how long to brush for.
But with good brushing technique, manual toothbrushes can often be almost as good – after all, the most important thing is that you brush twice a day for at least two minutes each time.