Background: Depending on the cause of discoloration, bleaching materials and other factors, vital dental bleaching techniques may be professional (in-office dental
bleaching), at-home night-guard bleaching and combined.
The main objective of this study was to determine, in vitro, tooth colour change
using external dental bleaching techniques with 16% and 30% carbamide peroxide
gel and to investigate the effect of concentration of carbamide peroxide gel on the
bleaching success.
Method: This study included 20 extracted intact human teeth. Teeth were divided
into two groups of ten each: the first group was bleached with 16% and the second
group with 30% carbamide peroxide gel. The procedure was repeated three times
for each tooth. The existing colour on each tooth was recorded using VITA classical shade guide A1-D4 before treatment, after each session and after bleaching was
completed.
Results: A significant difference (p < 0.01) was found between the first and the second bleaching treatment, for both concentrations (Exact binomial test). A significant
difference (p <0.05) was also present between the second and the third treatment,
while no statistically significant difference was found between the first and the third
bleaching treatment, for both concentrations. There was no statistically significant
difference between groups based on degree of tooth shade (χ2 test).
Conclusion: The teeth bleaching technique with 16% carbamide peroxide gel and the
teeth bleaching technique with 30% carbamide peroxide gel have shown the same
efficiency in changing the tooth colour.
