This Review Title is After using for two hours, zero removal of calculus and the content is: After using for two hours, zero removal of calculus. I will try again tomorrow. So far, only a headache from the vibration. The manual remover probably works better, at least I can see something removed when I tried it. I see absolutely no results with this vibrating unit. If I find a magical way to make it effective I will update this review.  Would definitely not recommend at this point..There are other information for this review, one is This reviewer did purchase it and the other is 14 people think this review is helpful.