Objective    To evaluate the efficacy and safety of teeth bleaching by Beyond cold light whitening kit.      Methods    Sixty-five subjects including 31 with yellow teeth (496 teeth

natural and acquired yellow stained teeth) and 34 with tetracycline stained teeth (544 teeth) were enrolled into the study. Efficacy was assessed by VITA shade scores and safety evaluation was performed by examining the examination of dentin hypersensitivity

dental pulp stimulation and gingival irritation.      Results    Beyond cold light whiting kit was significantly effective in lighting tooth shade both in yellow tooth and tetracycline stained tooth. After treatment

the subjects with yellow tooth exhibited an overall mean 6.32-shade improvement from baseline and the effective rate was 100%. The subjects with tetracycline stained tooth exhibited an overall mean 5.37-shade improvement from baseline and the effective rate was 98.5%. Although high shade improvement was got in heavy tetracycline stained tooth

the real color were not satisfactory to patients and doctors. Tooth sensitivity occurred in 84.6% subjects during treatment and 10.5% were accompanied with eroded gum. After bleaching

about 89.2% subjects complained of tooth sensitivity and about 13.8% patients of dental pulp stimulation. Tooth hypersensitivity persisted about 24-72 h

then quitted.     Conclusion    Beyond cold light whiting kit is effective to yellow teeth

slight and moderate tetracycline stained tooth. The kit has light stimulation to dentin and dental pulp

and tooth hypersensitivity is transient and recoverable.