Clinical evaluation of three months' nightguard vital bleaching on tetracycline-stained teeth using Polanight 10% carbamide gel: 2-year follow-up study.

Nightguard vital bleaching (NGVB) has been applied as a safe and effective bleaching procedure with a wide variety of commercial products consisting of carbamide peroxide-based gels, but there have been few reports on tooth bleaching for tetracycline-stained teeth. The purpose of this study was to evaluate the bleaching effects on teeth discolored by tetracycline with 3 months' active treatment, and to investigate the participant satisfaction, the shade stability, and the post-treatment side effects 2 years after the treatment. A custom-made tray with Polanight 10% carbamide peroxide gel was applied to both the incisal and premolar teeth (10 teeth of each participant), and the participants were directed to wear the tray every night over the course of the 3 months. The whiteness-blackness difference (L*) became lighter within 3 months and the lightness remained until 2 years later. Tooth color changes were remarkable in both redness-greenness difference (a*) and yellowness-blueness difference (b*). No obvious shade change or slight darkening was recognized 2 years post-treatment. The means of the color difference (DeltaE*) at 3 months, 6 months, 1 year, and 2 years were 13.74, 14.02, 12.17, and 11.81, respectively. All participants were satisfied with the shade change of their teeth, but three participants complained of slight hypersensitivity. One participant complained of cold or hot pain in daily life until 6 months after the treatment. These side effects were alleviated within 1 year. The results suggested that the standard treatment period of NGVB with Polanight for tetracycline-discolored teeth may be determined to be 3 months.