Some toothbrushes have angled bristles, others straight. So is one type better? Dentists say no.
''It's more related to technique than the way the bristles come out," says Sesemann.
What is important when buying a toothbrush? Bristles that are too stiff can aggravate the gums. The ADA recommends a soft-bristled brush.
''Bristles should be sturdy enough to remove plaque but not hard enough to damage [the teeth] when used properly," says Price. He doesn't recommend "natural" bristles such as those made from animal hair or boar bristle.
cited from http://www.webmd.com/oral-health/healthy-teeth-10/brushing-teeth-mistakes