The bleaching efficacy of carbamide peroxide gels containing potassium nitrate desensitizer

Effect of 1.5% potassium oxalate on sensitivity control, color change, and quality of life after at-home tooth whitening: A randomized, placebo-controlled clinical trial

OBJECTIVE

This clinical trial evaluated the effect of 1.5% potassium oxalate (PO) in controlling sensitivity and color change after at-home tooth whitening. It also evaluated the influence of PO on health-related quality of life (HRQoL) and the degree of patient satisfaction after bleaching treatment.

MATERIALS AND METHODS

Fifty volunteers were randomized into two groups (n = 25): At-home bleaching gel with 22% carbamide peroxide for 45 min + placebo gel (GP) or 1.5% PO (GPO) for 10 min. The intensity of tooth sensitivity was assessed daily through the visual analog scale. The color analysis was performed three times: baseline, 21 days, and 1 month after the last application of the whitening gel. The impact of the oral condition on the patient's quality of life (OIDP) was used to measure the impact caused by the whitening treatment in relation to the individuals' ability to carry out their daily activities and its influence on HRQOL.

RESULTS

No difference in tooth sensitivity was observed (p > 0.05). In addition, there was no difference in color change between groups (p > 0.05). However, there was an intragroup statistical difference throughout the evaluation period (p <0.05). The OIDP analysis showed a statistical difference between the groups (p > 0.05) and there was no difference between the groups regarding the degree of satisfaction with the bleaching (p > 0.05).

CONCLUSIONS

The 1.5% PO was effective in preventing sensitivity and did not interfere with tooth whitening. Desensitizing therapy had a positive impact on quality of life and patient satisfaction.

In-office dental bleaching with violet-LED: bleaching efficacy and pulpal temperature rise

Objectives

This study evaluated the bleaching efficacy of different in-office protocols associated with violet light emitting diode (V-LED), and measured the pulpal temperature rise caused by V-LED with or without gel application.

Materials and Methods

Bovine incisors were distributed in 4 groups (n = 10): VL – V-LED; HP – 35% hydrogen peroxide (control); HYB – hybrid protocol, V-LED applied without gel for 10 irradiation cycles followed by V-LED applied with gel for another 10 irradiation cycles; and HPVL – gel and V-LED applied for 20 irradiation cycles. Three bleaching sessions were performed with 7-day intervals. Bleaching efficacy was evaluated with ΔEab*, ΔE₀₀ and ΔWI_D. Data were recorded at baseline, 7, 14, 21 and 70 days. For pulpal temperature rise, thermocouples were placed inside the pulp chamber of human incisors. To determine intrapulpal temperature, the teeth were irradiated with V-LED with or without application of bleaching gel. Color difference data were analyzed by 2-way repeated measures ANOVA and Tukey’s test. Pulpal temperature was analyzed by t-test (α = 5%).

Results

VL exhibited lower color (ΔEab* and ΔE₀₀) and whiteness changes (ΔWI_D) than the other groups. HPVL presented higher color change values than HYB. HYB and HPVL showed not different ΔWI_D values; and HP showed the highest whiteness changes at all times. There were significant differences comparing ΔT with gel (8.9°C) and without gel application (7.2°C).

Conclusions

HPLV was more efficient than HYB. The 2 protocols with VL showed similar results to control. Gel application combined with VL promoted higher pulpal temperature than to the no gel group.

Efficacy and tooth sensitivity of at-home bleaching in patients with esthetic restorations: a randomized clinical trial

OBJECTIVES

This study aims to evaluate the color change and tooth sensitivity (TS) caused by at-home bleaching in patients with sound and with restored teeth.

METHODS

Forty patients were selected according to the inclusion and exclusion criteria and divided into two groups: So (patients with six caries-free maxillary anterior teeth) and Re (patients with at least one restoration in the six maxillary anterior teeth). Both groups were bleached with 10% carbamide peroxide (CP) at-home bleaching. The color change (CIELab [ΔE*_ab], CIEDE00 [ΔE₀₀], and whiteness index [∆WI_D]) were assessed using a spectrophotometer at baseline, 2 weeks, and 1 and 3 months after bleaching. Patients recorded their TS using a numeric rating scale (0-4). Data of color change were submitted to Student's T-test. The absolute risk and intensity of TS were compared using Fisher's and the Mann-Whitney tests, respectively (α = 0.05).

RESULTS

Higher ΔE*_ab, ΔE₀₀, and ∆WI_D values were observed for So in relation to Re after all recall rate (p < 0.0001). No significant differences were observed regarding of bleaching-induced TS (p > 0.9).

CONCLUSIONS

At-home dental bleaching with 10% CP generated the same pattern of TS in patients with or without restorations. However, in patients with restored teeth, it produced a lower color change after 2 weeks of bleaching.

CLINICAL SIGNIFICANCE

After 2 weeks of at-home bleaching, a lower whitening effect was observed in patients with anterior restorations when compared with patients with sound teeth.

TRIAL REGISTRATION

ClinicalTrials.gov identifier RBR-52j6gmg.