I'm not 高手. You might want to consider where you can get the replacement
brush heads?
IMHO, I'd rather go w/ Philips or Oral B toothbrush. Oral B's brushhead is
usually cheaper than Philips so it has lower ongoing cost.
Like this one:
New Oral-B Model S-200 Sonic Complete for $55 at eBay http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=13091829