In vitro evaluation of the effect of different bleaching varnishes: Hydrogen peroxide penetration into the pulp chamber and color change.

OBJECTIVE: To evaluate the penetration of hydrogen peroxide (HP) into the pulp chamber and the color change of different bleaching varnishes in low concentrations used for at-home bleaching. MATERIALS AND METHODS: Ninety healthy premolars were used, randomly distributed into nine groups (n = 10) according to bleaching varnish (PL, PolaLuminate; VS, VivaStyle Paint On Plus; CA, Cavex Bite&White whitening pen and; AW AlignerWhite) and time (10 and 30 min), and a control group (no bleaching). The penetration of HP was evaluated by UV-Vis spectroscopy. To evaluate the color change (ΔEab , ΔE00 , ΔWID ) a digital spectrophotometer was used (α = 0.05). RESULTS: The AW group in 10 min and the control group showed similar and lower HP penetration in the pulp chamber when compared to the other groups (p = 0.003). Increasing the application time to 30 minutes elevated the amount of HP inside the pulp chamber for all groups (p = 0.003), except for PL (p > 0.05). When applied for 30 min all bleaching varnishes showed higher color change (ΔWID ) when compared to 10 min (p = 0.04). CONCLUSIONS: For all bleaching varnishes evaluated, PolaLuminate applied for 30 min showed lower penetration into the pulp chamber and higher bleaching effects. CLINICAL SIGNIFICANCE: The use of bleaching varnishes seems promising for teeth bleaching, but it varies according to user product and protocol.

Effect of the type of application tip for 35% hydrogen peroxide on bleaching efficacy and tooth sensitivity: A randomized clinical trial.

OBJECTIVES: Evaluate the bleaching efficacy (BE) and tooth sensitivity (TS) of in-office bleaching using different application tips. METHODS: Forty-eight participants were selected (split-mouth), one to receive bleaching with an attached brush tip and one with a conventional tip. The procedure was performed with Whiteness Automixx Plus 35%. The BE was evaluated at the beginning, weekly, one and 12 months post-bleaching with a Vita Easyshade spectrophotometer (ΔE*ab, ΔE00, and WID) and with Vita classical A1-D4 and Vita Bleachedguide shade guides units (ΔSGU). Absolute risk and intensity of TS were recorded using the Visual Analogue Scale. The equivalence of BE was analyzed using the two one-sided t-tests for paired samples. The absolute risk of TS was evaluated using the McNemar test, and the TS intensity was measured with the paired t test (α = 0.05). RESULTS: The equivalence of BE was observed for both groups in all color evaluations (p > 0.05). A lower absolute risk and intensity of TS were observed for the attached brush tip when compared with the conventional tip (p < 0.003 and p < 0.0001). CONCLUSION: Using an attached brush tip showed the same BE as a conventional tip. However, for the attached brush tip, there was a reduction in TS. CLINICAL SIGNIFICANCE: The applicator-attached brush tip is recommended for in-office dental bleaching, because of the possible reduction in risk and intensity of TS.

Use of infrared photobiomodulation with low-level laser therapy for reduction of bleaching-induced tooth sensitivity after in-office bleaching: a double-blind, randomized controlled trial.

The purpose of this study is to evaluate the use of infrared photobiomodulation with low-level laser therapy (PBM) to reduce bleaching-induced tooth sensitivity (TS) after in-office bleaching. Eighty-three participants were randomized in blocks into two groups. In the experimental group, the patients received an application after each session of in-office bleaching (35% hydrogen peroxide, 1 × 50 min; 2 sessions with 1-week interval), while the laser application was simulated in the control group. The PBM system was operated in continuous mode, using 3 J of energy. A dose of 100 J/cm2 was applied for 30 s with 808 nm (100 mW of power) in the middle third of the crown. The risk and intensity of TS were recorded immediately after bleaching, 1 h, 24 h, and 48 h after each bleaching session, with a visual scale analog (0-10) and a five-point numerical scale (0-4). The color was recorded at the beginning, weekly, and 1 month after the end of the bleaching (VITA Classical, VITA Bleachedguide, and digital spectrophotometer). The risk of TS was 98% (95% CI 88 to 99%) for the laser group and 95% (95% CI 83 to 99%) for the control (RR = 1.03; 95% CI 0.94 to 1.12; p = 1.0). Similarly, no difference in the intensity of TS was detected for both pain scales (p > 0.65). Improvement in color change, regardless of the group, was observed (p > 0.15). The application of an PBM did not reduce the risk and intensity of TS when applied after the procedure using the parameters recommended by the manufacturer.Trial registration number and date of registration: RBR-4HCVSG-04/06/2019.

Use of an applicator brush with high concentration bleaching gels.

OBJECTIVES: To evaluate in vitro two high concentration self-mix bleaching gels (35% or 37.5%) with different application tips (with or without an applicator brush) during in-office bleaching. MATERIALS AND METHODS: Healthy premolars were randomly assigned to five groups (n = 8): no treatment; 35% HP without applicator brush, 35% HP with applicator brush, 37.5% HP without applicator brush, and 37.5% HP with applicator brush. After the procedures, the concentration of HP transferred into the pulp chamber was evaluated using UV-Vis. The amount of gel used in each group was measured on a precision analytical balance. Color change (ΔEab, ΔE00, and ΔWID) was evaluated with a digital spectrophotometer. Initial concentration was measured by titration with potassium permanganate. The pH was evaluated using a digital pH meter. The data from each test were submitted to nonparametric tests (α = 0.05). RESULTS: Using a tip with an applicator brush expended less gel and left a lower amount of HP inside the pulp chamber compared to the tip without a brush for both bleaching gels (p < 0.0003), although no significant difference in color change was observed (p < 0.05). The 37.5% HP showed a more stable and less acidic pH and a lower amount of HP in the pulp chamber than the 35% HP (p < 0.00001). CONCLUSION: The HP penetration into the pulp chamber was lower when using an applicator with a brush tip than when using one with a conventional tip. As for the color, both tips were considered to lighten teeth. CLINICAL SIGNIFICANCE: For the application of a self-mixing high concentration in-office bleaching gel, a brush tip should be recommended because its use diminishes the penetration of HP into the pulp chamber and wastes less bleaching gel.

Gingival irritation in patients submitted to at-home bleaching with different cutouts of the bleaching tray: a randomized, single-blind clinical trial.

OBJECTIVES: This split-mouth randomized, single-blind clinical trial evaluated the gingival irritation (GI) of at-home bleaching with individual trays of different cutouts, as well as the tooth sensitivity (TS) and color change. MATERIALS AND METHODS: One hundred and twenty patients were randomized as to which side would receive the type of bleaching tray cutout: scalloped (in the gingival margin) and nonscalloped (extended from the gingival margin). The at-home bleaching was performed for 30 min with 10% hydrogen peroxide (HP) for 2 weeks. The absolute risk and intensity of GI and TS were assessed with a visual analog scale. Color change was assessed using a digital spectrophotometer and a color guide (α = 0.05). RESULTS: The proportion of patients who experienced GI was 57.5% (odds ratio 95% CI = 1.1 [0.7 to 1.8]), with no significant difference between groups (p = 0.66). The proportion of patients who experienced TS was 64.1% (odds ratio 95% CI = 1.0 [0.6 to 1.6]), with no significant difference between groups (p = 1.0). There is equivalence of scalloped and noscalloped groups for GI intensity (p < 0.01). Significant whitening was detected for both groups. Although some differences were observed between groups (CIELab and CIEDE00; p < 0.02), these were below of the considered clinically noticeable. CONCLUSIONS: The different cutouts of trays proved to be equivalent when regarding gengival irritation and tooth sensitivity when 10% HP for at-home bleaching was used. Significant color change was observed in both groups. However, significant differences detected between groups are not considered clinically noticeable. TRIAL REGISTRATION: Brazilian Clinical Trials Registry (RBR-2s34685). CLINICAL RELEVANCE: Scalloped or not, the individual trays for at-home bleaching could be considered a clinician's decision.

In-office bleaching with a commercial 40% hydrogen peroxide gel modified to have different pHs: Color change, surface morphology, and penetration of hydrogen peroxide into the pulp chamber.

OBJECTIVE: In-office bleaching gels are usually marketed in different pHs. This study is aimed at evaluating the efficacy, enamel surface morphology and concentration of hydrogen peroxide (HP) in the pulp chamber of teeth bleached with 40% HP with different pHs. MATERIALS AND METHODS: Forty premolars were randomly divided according to bleaching gel pH: 5.1, 6.3, 7.0, and control (no bleaching). Teeth were prepared, an acetate buffer was placed in the pulp chamber and teeth were bleached with two 20-minutes applications. The amount of HP was determined on a UV-VIS spectrophotometer. Color change was assessed by using a digital spectrophotometer before and 1 week after bleaching treatment. Five additional premolars were divided into four parts, assigned to the same groups above for analysis under scanning electron microscope. Data were subjected to anova and Tukey's tests (alpha = 0.05). RESULTS: The group pH 5.1 showed the highest HP diffusion in the pulp chamber (P < .001). No significant difference was detected in color change (P = .51). All groups presented the same pattern of enamel demineralization. CONCLUSIONS: The bleaching agent with pH 5.1 presented the highest HP amounts in the pulp chamber, but color change and enamel morphology were similar among groups. CLINICAL SIGNIFICANCE: Regardless of the pH, the bleaching effect can be observed in teeth submitted to high concentrations of HP, but a higher permeability of HP was found in the pulp chamber of teeth bleached with more acidic bleaching agents. Based on that, we suggest the use of alkaline gels for in-office bleaching to minimize damage to the pulpal tissue.

Does simultaneous versus individual-arch at-home dental bleaching regimen influence patient satisfaction? A randomized clinical trial.

OBJECTIVE: Our randomized, parallel and single-blinded clinical trial evaluated patient level of discomfort during at-home bleaching testing the equivalence between two different protocols for the use of bleaching trays (simultaneous vs. single arch), as well as tooth sensitivity (TS), gingival irritation, (GI) and bleaching efficacy (BE). MATERIALS AND METHODS: We randomized 100 patients into: simultaneous (n = 50) and single arch (n = 50). At-home bleaching was performed with 10% hydrogen peroxide (HP) for 2 weeks for simultaneous group and 4 weeks for single arch group. We assessed patient level of discomfort using 9-item questionnaire. The TS and GI, as well as BE using spectrophotometer and color guide were assessed using the visual analog scale (0-10). Data from level of discomfort and BE were evaluated by Student's t test. The TS and GI were compared using the relative risk and confidence interval (α = 0.05). RESULTS: Only tray adaptation showed a significant effect after the second week (p < 0.002). There was equivalence between groups for level of discomfort (p < 0.01). We found no significant intergroup differences for the risk of TS or GI, nor for intensity. We observed no significant differences between them regarding bleaching efficacy (p > 0.21). CONCLUSIONS: A simultaneous-use protocol for customized at-home dental bleaching trays proved to be equivalent to using single arch for patient level of discomfort and bleaching efficacy, with no significant increase in adverse effects. CLINICAL SIGNIFICANCE: Clinicians may decide whether to use a simultaneous or single arch protocol for tray usage; however, bleaching was achieved more quickly when the trays were worn simultaneously.

In-office bleaching with complete cervical third protection protocol: A split-mouth, double-blind, randomized clinical trial.

PURPOSE: To evaluate the bleaching sensitivity and the bleaching effectiveness of in-office bleaching, following a protocol of complete cervical third protection with gingival dam in comparison with a traditional manner of applying gingival dam (used only in the gingival sulcus area). METHODS: 35 participants were selected for this double-blind split-mouth randomized clinical trial. The control group received the gingival barrier in the traditional manner, and in the experimental group the barrier was extended by about 3 mm to include the cervical region. The bleaching agent was applied in two sessions. The risk and intensity of bleaching sensitivity were assessed using two scales. The bleaching effectiveness was evaluated with a digital spectrophotometer with the tip placed in the cervical area. The absolute risk of bleaching sensitivity was compared by the McNemar's test and bleaching effectiveness (ΔEab, ΔE00 and ΔWi) and intensity of bleaching sensitivity was evaluated by Wilcoxon-paired test (α= 0.05). RESULTS: No significant difference at risk (P= 1.0) and intensity of bleaching sensitivity (P> 0.45) was seen between groups. After 30 days, bleaching effectiveness had no statistical difference between the groups (P> 0.09). CLINICAL SIGNIFICANCE: Extending the barrier in the cervical region of teeth did not reduce the risk and intensity of bleaching sensitivity, nor jeopardize the bleaching effectiveness.

A novel carbamide peroxide polymeric nanoparticle bleaching gel: Color change and hydrogen peroxide penetration inside the pulp cavity.

OBJECTIVE: This study evaluated the hydrogen peroxide (HP) penetration inside the pulp cavity and the color change of teeth submitted to the 15% carbamide peroxide (CP) nanoparticle bleaching gel at several application times. MATERIALS AND METHODS: Premolars were divided into nine groups (n = 6) according to 15% CP bleaching agents (nanoparticle and commercial) and to application times (15, 30, 45, and 60 minutes). A negative control was exposed to ultra-purified water. After a whitening procedure, the HP concentration (µg/mL) inside the pulp cavity was assessed via spectrophotometry. The color change (ΔE* and ΔE00*) was evaluated with a spectrophotometer. Data were analyzed via two-way ANOVA and Tukey (α = 0.05). RESULTS: A lower concentration of HP was detected for CP nanoparticle gel after 30 and 45 minutes of whitening procedure (P = .001). The bleaching groups promoted a higher color change (ΔE* and ΔE00*) regardless of the application time (P = .0001). CONCLUSIONS: The CP nanoparticle gel reduced HP inside the pulp cavity, and showed effective bleaching compared with CP commercial gel. CLINICAL SIGNIFICANCE: Using 15% carbamide peroxide nanoparticle bleaching gel decreased the HP penetration inside the pulp cavity and may decrease bleaching-induced tooth sensitivity in at-home bleaching.

The influence of dental bleaching on patient's quality of life: A multistudy analysis of aesthetic and psychosocial outcomes.

OBJECTIVES: To assess the Quality of Life (QoL) of participants treated with dental bleaching using different techniques by administering two questionnaires Oral Health Impact Profile (OHIP-14) and Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ), as well as the bleaching efficacy and tooth sensitivity (TS). MATERIALS AND METHODS: Secondary results for nine randomized clinical trials were included, involving 489 participants who underwent bleaching procedures. The questionnaires were applied at baseline and 30-day post-bleaching. Bleaching efficacy (ΔSGU/ΔEab) and TS were also evaluated (VAS/NRS). The effect of bleaching on aesthetic self-perception was evaluated using the Paired t-test. The Kruskal-Wallis test assessed variations by technique. Also, the correlations between questionnaires and outcomes was evaluated (α = 0.05). RESULTS: After the bleaching treatment, both questionnaire revealed significant differences compared to the baseline, regardless of the factor evaluated (p < 0.05), except for Physical pain in OHIP-14 (p = 0.53). No correlation was found between OHIP-14 and bleaching efficacy (p < 0.008). A significant correlation was found between bleaching efficacy and dental self-confidence, indicating that dental self-confidence increased as the number of SGU (ΔSGU) increased, while social impact (ΔEab) and aesthetic concern (ΔSGU) decreased. Additionally, a significant correlation was observed between TS and OHIP-14 (Physical pain). For PIDAC, both dental self-confidence and psychological impact were correlated with TS in the VAS. CONCLUSION: Subjects who underwent dental bleaching treatment improved their self-perception and dental self-confidence. Dental bleaching, besides enhancing the patient's smile, also improves their self-esteem. CLINICAL RELEVANCE: Dental bleaching, besides improving the patient's smile, also enhances their self-esteem.

Effect of whitening toothpastes with different hydrogen peroxide concentrations: Penetration into the pulp chamber and color change.

OBJECTIVES: This study evaluated the efficacy of simulated brushing with toothpastes containing different concentrations of hydrogen peroxide (HP) in pulp chamber penetration and color change. Also, physical-chemical properties (concentration, pH and viscosity) were evaluated. METHODS: Forty-nine premolars were divided into seven groups (n = 7): untreated (control); whitening gel (White Class 6 %, 6 %BG) with one 90  min application (6 %BG 90  min) and 14 applications of 90  min (6 %BG 14×90 min); toothpastes (Colgate Luminous White Glow 3 %, 3 %TP; Crest 3D White Brilliance 4 %, 4 %TP; Colgate Optic White Pro-Series 5 %, 5 %TP) and 6 %BG toothbrushing for 14 applications of 90 s. HP penetration into the pulp chamber was measured through UV-Vis spectrophotometry and color change with a spectrophotometer (ΔEab, ΔE00, and ΔWID). Initial concentration, pH, and viscosity were measured through Titration, Digital pH-meter, and Rheometer, respectively. Statistical analysis used one-way ANOVA and Tukey's test (α = 0.05). RESULTS: 6 %BG (14×90 min) and 4 %TP groups showed acidic pH and higher concentrations of HP in the pulp chamber compared to the other groups (p < 0.05). On the other side, 3 %TP and 5 %TP groups showed alkaline pH, higher viscosity between the toothpastes and lower HP penetration (p < 0.05). The 6 %BG AH (14×90 min) group exhibited the most significant color change (ΔEab, ΔE00, and ΔWID) (p < 0.05). CONCLUSIONS: Brushing with whitening toothpaste with an acidic pH leads to greater HP penetration into pulp chamber; but, even when a high concentrated HP whitening toothpaste was used, a lower whitening effect was observed when compared to a two-week at-home bleaching. CLINICAL SIGNIFICANCE: Whitening toothpastes containing up to 5 % HP produced lower whitening effect than two-week at-home bleaching. Additionally, HP was detected within the pulp chamber which can potentially impact in tooth sensitivity.