The principle of dental instrument is cold light whitening, itself cold light whitening on the teeth and gums have a certain degree of stimulation, if the lack of proper operation, the lack of good protection of the teeth and gums, to do cold light whitening on the teeth and gums are harmful. Nowadays, many patients inquired about the sale price of about 300 yuan, can be operated at home by their own teeth whitening instrument, I personally recommend that we firmly do not use, this kind of teeth whitening instrument does not have any protection for the teeth and gums. In addition, the operation does not have an effective assessment of the teeth and pulp, so it will result in an overdose, which can easily cause tooth sensitivity, pulpitis and gum recession. It is recommended that if there is a need for whitening, please visit the dentistry department of a regular hospital for cold light whitening.