"Why is the toothbrush making so much noise?"에 답변I've noticed these brush heads don't quite fit properly. They have a habit of vibrating loose and make a terrible noise. It's the plastic nipple at the base of the stem vibrating against the metal band at the base of the brush head making this highly annoying high pitched whine. Not all brush heads do this, but so far, all of the Diamond Head brush heads that I've purchased do. What a joke for something that costs such a pretty penny.