USE OF DIFFERENT CONCENTRATIONS OF CARBAMIDE PEROXIDE FOR BLEACHING TEETH - AN IN-VITRO STUDY

Objective: This in vitro study compared the shade changes in extracted teeth during 2 weeks' whitening with 5%, 10%, or 16% carbamide peroxi de, Method and materials: After color calibration the sole examiner se lected IIO extracted unrestored, noncarious teeth, shade A3 or darker on a value-oriented guide, The teeth were randomly distributed into eq ual color groups, The control group (II teeth) was treated with 0.9% s aline, while the experimental groups (33 teeth each) were treated with 5%, 10%, or 16% carbamide peroxide. The solutions remained on the tee th for 8 hours. The teeth and tray were rinsed with tap water for 2 mi nutes, then rehydrated in 0.9% saline for 16 hours in the humidifier: The shade was assessed and the process was repeated daily for 2 weeks. Results: Repeated-measures analysis of variance indicated a significa nt difference in overall shade values between the control and all carb amide peroxide-treated groups at clays 8 and 15. A Kaplan-Meier Surviv al Analysis indicated a quicker two-tab color change for the 10% and 1 6% groups than the 5% group. However continuation of the 5% treatment to 3 weeks resulted in shades that approached the 2-week 10% and 16% v alues. Conclusion: Lower concentrations of carbamide peroxide take lon ger to whiten teeth but eventually achieve the same result as higher c oncentrations. Higher concentrations may cause increased sensitivity.