pH-changes during intracoronal bleaching: an in vivo study
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Daphne Camara Barcellos1, Alessandra Buhler Borges, Regina Celia dos Santos Pinto Silva
1Department of Restorative Dentistry, São Josédos Campos School of Dentistry, São Paulo State University, São Paulo, Brazil.
Objectives:
This study aimed to measure pH changes during 14 days intracoronal bleaching with hydrogen peroxide/sodium perborate and carbamide peroxide/sodium perborate.
Materials And Methods:
Twenty patients presenting endodontically treated central maxillary incisors with color alterations were divided in two groups (n = 10): Group CP + SP: 37% carbamide peroxide + sodium perborate paste; Group HP + SP: 30% hydrogen peroxide + sodium perborate paste. The pH values were measured using a digital microprocessor at different times: Baseline, 2, 7 and 14 days. Data were analyzed with two-way ANOVA followed by Tukey's test (α = 0.05).
Results:
ANOVA showed p < 0.00 which indicated significant difference between the groups. The mean values (± sd) and the results of the Tukey´s test were: HP + SP/14 days-7.98 (±0.58)a; HP + SP/7 days-8.59 (±0.18)b; HP + SP/2 days- 8.83 (±0.32)bc; HP + SP/Baseline-8.83 (±0.01)bc; CP + SP/ Baseline-8.89 (±0.01)bc; CP + SP/14 days-9.11 (±0.58)cd; CP + SP/7 days-9.54 (±0.16)de; CP + SP/2 days-9.66 (±0.08) de. The group HP + SP resulted in significantly lower pH values compared with group CP + SP.
Conclusion:
It can be concluded that both associations showed alkaline pH values; however, there was significant reduction in the pH values of the 30% hydrogen peroxide associated with sodium perborate after 14 days.
Clinical Significance:
The association of hydrogen peroxide and carbamide peroxide with sodium perborate paste presented alkaline characteristics during the 14-day evaluated period. Thus, regarding pH changes, both associations can be considered safe as intracoronal bleaching agents.
