Rh. Leonard et al., USE OF DIFFERENT CONCENTRATIONS OF CARBAMIDE PEROXIDE FOR BLEACHING TEETH - AN IN-VITRO STUDY, Quintessence international, 29(8), 1998, pp. 503-507
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.