tartar removal...man i've done this 2 years ago and i still can't forget how painful it was...and my teeth bleed non-stop for 2 days...no kidding, i need to gargle with water every few minutes...after woke up from sleep a thick layer of frozen blood stuck in my teeth...

well ONLY if u have a weak gum and don't consume much calcium though...if ur gum didnt bleed when brushing, then u won't have such things as i faced though