About 4 months ago I bought this ultra-sonic toothbrush. I am very satisfied. I usually had very strong tartar and plaque öftern also problems with smaller inflammation of the gums (canker sores). Everything significantly better. Technically, the part properly - no problems so far with battery, etc. For a comparison with other ultrasonic toothbrushes I did not (perhaps the others are similarly well). For those who have problems with tartar, etc., I can recommend an ultrasound toothbrush only strongly.