>>16370100you're most likely using it wrong.
only use the gentlest setting. if there's a setting with a "polishing/whitening effect" avoid it at all costs (this goes for toothpaste as well).
don't apply more force than necessary to reach between the gaps. the movement of the head will clean your teeth regardless.
time your brushing properly. never exceed 2 minutes for all the teeth. most electric toothbrushes have built in timers nowadays that tell you when you should brush a different part of the mouth or stop brushing.
and, perhaps most importantly, make sure your gums don't have periodontal disease. this might cause them to recede when you brush, regardless of your brushing technique
