Diferentes estratégias de uso do peróxido de hidrogênio a 6% no clareamento dental: estudos in vitro e ensaios clínicos

Abstract

The use of low concentrations for tooth bleaching is becoming increasingly widespread. On the market, there are different strategies available for the use of 6% hydrogen peroxide (HP) in tooth bleaching. However, there is still a lack of studies that demonstrate which of the most recent application alternatives are the most effective. Therefore, the aim of this doctoral thesis was to evaluate in vitro and clinical bleaching with 6% HP. To this end, 2 in vitro studies and 2 clinical studies were carried out. The first study compared 6% PH bleaching varnishes at different application times. This was an in vitro study with 90 premolars (n=10) and the penetration of PH into the pulp chamber (µg/mL) and the color change (∆Eab, ∆E00, ΔWID) were determined. The second study compared the effect of using different application tips, conventional (without a brush) and with a brush, with products containing PH at low (6%) and high (35%) concentrations. In it, the penetration of PH into the pulp chamber (µg/mL), the color change (∆Eab, ∆E00, ΔWID) and the amount of bleaching gel used (g) were evaluated in vitro with 40 premolars (n=8). The third study clinically analyzed in-office bleaching obtained with 6% PH in adolescents using the two tips, without a brush and with a brush, the same as those evaluated in the second study. The design was a randomized, split-mouth, double-blind clinical trial with 60 volunteers (n=60; 120 hemiarcades). The efficacy of the color change (∆Eab, ∆E00, ΔWID), the risk and intensity (VAS; 0-10) of tooth sensitivity (TS) and aesthetic self-perception (OES) were evaluated. The fourth and final study focused on clinically determining whether there was gingival irritation (GI) with or without the application of the gingival barrier in 6% PH bleaching in adolescents. A randomized, split-mouth, double-blind clinical trial was carried out with 60 volunteers (n=60; 120 hemiarcades). The risk and intensity (VAS; 0-10) of GI, the effectiveness of color change (∆Eab, ∆E00, ΔWID) and the impact of oral condition on quality of life (OHIP-14) were evaluated. The results were promising with the use of 6% PH. Although some differences were detected between the different forms of presentation, bleaching efficacy, low penetration into the pulp chamber, low risk and intensity of TS and GI were observed. Only a few bleaching varnishes did not show clinically acceptable bleaching. In the first clinical study, it was shown that the brush tip should be considered the first option for in-office bleaching because, in conjunction with the results of the in vitro study, it showed a lower amount of bleaching gel used, reduced PH penetration into the pulp chamber and, consequently, showed lower TS. The second clinical study showed that the step of applying the gingival barrier can be dispensed with for in-office bleaching with 6% PH, as it had no effect on GI. Finally, in-office bleaching with 6% PH had a positive impact on the patient's quality of life and produced an improvement in aesthetic self-perception.