Whitening toothpastes with hydrogen peroxide concentrations vs. at-home bleaching.

OBJECTIVES: To evaluate the effect of whitening toothpastes with different hydrogen peroxide (HP) concentrations on HP permeability, color change, and physicochemical properties, compared to at-home bleaching treatment. MATERIALS AND METHODS: Forty-nine premolars were randomized into seven groups (n = 7): untreated (control); at-home bleaching with 10% carbamide peroxide gel (AH; 10% CP) with 14 and 28 applications of 180 min each (AH [14 × 180 min] and AH [28 × 180 min]); three whitening toothpastes (3% HP; 4% HP and 5% HP) and 10% CP brushed 28 times for 90 s each (TB [28 × 90 s]). HP permeability was measured using a UV-VIS spectrophotometer and color change by a digital spectrophotometer (ΔEab, ΔE00, and ΔWID). Initial concentration, pH, and viscosity were measured through titration, digital pH meter, and rheometer, respectively. Statistical analysis included one-way ANOVA, Tukey's test, and Dunnett's test (α = 0.05). RESULTS: 4% HP group showed acidic pH, the lowest viscosity and the highest HP concentration into the pulp chamber (p < 0.05). The 10% CP groups had lower HP in the pulp chamber and greater color change than other groups (p < 0.05), except the 5% HP group in ΔEab and ΔE00. For ΔWID, the 10% CP AH groups showed greater whitening than other groups (p < 0.05). CONCLUSIONS: Whitening toothpaste with up to 5% HP resulted in higher HP permeability and less color change compared to 10% CP. Higher HP commercial concentrations in toothpaste increased whitening effect; however, acidic pH toothpastes exhibited greater HP permeability. CLINICAL RELEVANCE: Whitening toothpastes with high hydrogen peroxide concentrations were less effective than at-home bleaching, resulting in less color change and greater permeability of hydrogen peroxide, potentially increasing the risk of tooth sensitivity.

The decomposition rate and bleaching efficacy of in-office bleaching gels with different pHs: a randomized controlled trial.

BACKGROUND: To evaluate the decomposition rate of active hydrogen peroxide (HP) and bleaching efficacy during in-office bleaching using high-concentration HP gels with different pHs. METHOD: A randomized, parallel, double-blind controlled trial was conducted with 40 volunteers randomized into four groups (pH 5.4; pH 7.0; pH 7.7, and pH 8.0). During the first session in-office bleaching, approximately 0.01 g of the gel was collected and titrated with potassium permanganate to obtain the concentration of active HP and pH values were measured using an electrode. Bleaching efficacy was assessed using a spectrophotometer [∆Eab, ∆E00, and WID], Vita Classical and Vita Bleachedguide scales [∆SGU]. The decomposition rate of HP concentration and pH values change were calculated using ANOVA one-way. The bleaching efficacy was assessed using two-way repeated measures ANOVA. Tukey's test was applied as a post-hoc test (p < 0.05). RESULTS: All gels experienced decreasing HP concentration over time. pH 5.4 gel showed greatest reduction after 50 min (p < 0.001). pH 8.0 and 7.7 gels remained stable; pH 5.4 remained acidic, while pH 7.0 turned acidic (p < 0.001). No significant difference in bleaching degree was observed among gels. They all showed a similar and clinically important color change after two clinical sessions, remained stable 1-month post-treatment (p > 0.05). CONCLUSIONS: All bleaching gels kept at least 70% of their HP content after 50 min, suggesting that there is a surplus of HP. They provided similar whitening efficacy 1-month after bleaching. PRACTICAL IMPLICATIONS: It is possible that lower HP concentrations may be equally effective in achieving desired results while reducing the potential for side effects. CLINICAL TRIAL REGISTRY NAME: RBR-35q7s3v.

At-home bleaching with carbamide peroxide with concentrations below 10%: bleaching efficacy and permeability in the pulp chamber.

OBJECTIVES: To evaluate the bleaching efficacy and permeability of hydrogen peroxide (HP) in the pulp chamber of human teeth bleached with lower concentrations of carbamide peroxide gel (4%, 5% and 7% CP). MATERIALS AND METHODS: Bleaching gels with lower concentrations were formulated and a commercial standard gel, 10% CP, was used as a reference. Fifty-six human premolars were randomly divided into four groups. Applications of the bleaching gel were made for 3 h for 21 days. The bleaching efficacy was evaluated by digital spectrophotometry on 1, 7, 14 and 21 days, with analysis in the ∆Eab, ∆E00 and WID color spaces. The concentration of HP in the pulp chamber was measured in the same periods by UV-Vis spectrophotometry (µg/mL). Two-way repeated analysis of variance (ANOVA) examined bleaching efficacy and HP permeability, followed by Tukey's post-hoc test (α = 0.05). RESULTS: All groups showed significant color changes, with no statistical differences after the second and third week of bleaching (p > 0.05). The 'time' factor was statistically different (p < 0.05), increasing the bleaching efficacy throughout the treatment. The 4% CP group had lower HP levels in the pulp chamber (p < 0.05). CONCLUSIONS: The results seem promising, revealing that low concentration gels are as effective as 10% CP with the benefit of reducing the amount of HP in the pulp chamber. CLINICAL RELEVANCE: Low concentration 4% PC and 5% PC maintains bleaching efficacy, reduces the penetration of HP peroxide into the pulp chamber, and may reduce tooth sensitivity.

Bleaching efficacy of in-office dental bleaching with different application protocols: a single-blind randomized controlled trial.

OBJECTIVE: This randomized controlled trial aimed to evaluate the equivalence in the color change, adverse effects, self-perception (AS) and the impact on oral condition (IO) of participants submitted to different application protocols of in-office dental bleaching. MATERIALS AND METHODS: 165 participants were bleached with a 35% hydrogen peroxide gel (Total Blanc Office One-Step, DFL), according to the following protocols: (1) 2 applications of 20-min each (2 × 20 min); (2) 1 × 40-min and; (3) 1 × 30-min. The color change was evaluated with the Vita Easyshade spectrophotometer, Vita Classical and Vita Bleachedguide scales. The intensity and risk of tooth sensitivity (TS) and gingival irritation (GI) were recorded using a 0-10 visual analogue scale (VAS). AS and IO was assessed before and after the bleaching procedure using the Orofacial Aesthetic Scale and Oral Health Impact Profile-14, respectively. RESULTS: Equivalent color change were observed (p < 0.001), with no significant difference between groups. The group 2 × 20 min presented the highest risk of TS (76%, 95% CI 63 to 85), compared to the 1 × 30 min (p < 0.04). The intensity of TS and GI and the risk of GI was similar between groups (p > 0.31). Irrespectively of the group (p = 0.32), significant improvements were observed for all items of AS and IO after bleaching (p < 0.02). CONCLUSIONS: The 1 × 30 min protocol produced equivalent color change to the other bleaching protocols with reduced risk of TS and shorter application time. CLINICAL RELEVANCE: A more simplified application regimen of a single application of 30 min yields effective bleaching and patient satisfaction while minimizing undesirable side effects and improving patient satisfaction.

Low and high hydrogen peroxide concentrations of in-office dental bleaching associated with violet light: an in vitro study.

OBJECTIVES: This study aims to assess hydrogen peroxide (HP) penetration within the pulp chamber, color change (CC), physical-chemical properties, and temperature using in-office different concentration bleaching gels with or without violet light. MATERIALS AND METHODS: Fifty teeth were divided into five groups (n = 10) based on the HP concentration bleaching gels used (6% and 35%) and the used violet light (with or without). HP penetration within the pulp chamber was measured using UV-Vis. The CC was evaluated with a digital spectrophotometer. Initial and final concentration, and pH were measured through titration, and a Digital pHmeter, respectively. Temperature analyses were measured through a thermocouple. Statistical analysis included two-way ANOVA, Tukey's, and Dunnett's test (α = 0.05). RESULTS: The presence of violet light did not affect the amount of HP within the pulp chamber, or the CC (p > 0.05). Greater penetration of HP was observed within the pulp chamber, as well as CC when using 35% HP (p < 0.05). The final concentration of both gels was lower than the initial concentration, regardless of the use of violet light (p < 0.05). The initial and final pH levels remained neutral and stable (p > 0.05). The pulp temperature increased when the gels were used in conjunction with violet light (p < 0.05). CONCLUSIONS: Using violet light in conjunction with 6% or 35% HP does not alter the physical properties of the bleaching agents, the penetration of HP or enhance color change. However, an increase in temperature was observed when violet light was applied associated with bleaching gels. CLINICAL RELEVANCE: While the simultaneous use of violet light with hydrogen peroxide 6% or 35% does not alter the material's properties, it also does not bring benefits in reducing hydrogen peroxide penetration and improving color change. Furthermore, the use of violet light increases pulp temperature.

Evaluation of hydrogen peroxide permeability, color change, and physical-chemical properties on the in-office dental bleaching with different mixing tip.

OBJECTIVE: This study aims to assess hydrogen peroxide (HP) penetration into the pulp chamber, color change (CC), physical-chemical properties, and material wastage (MW) and material used (MU) in mixing tips when using in-office bleaching gels with two different mixing tips. MATERIALS AND METHODS: Forty teeth were divided into five groups (n = 8) based on the bleaching gels used (Pola Office +37.5% [PO+] and Whiteness HP Automixx Plus 35% [AM+]) and the mixing tip types (T-Mixer and Helical). A negative control group was treated with ultra-purified water. HP concentration was measured using UV-Vis, and CC was evaluated with a digital spectrophotometer. Initial concentration, pH, and viscosity were measured through Titration, a Digital pH meter, and Rheometer, respectively. MW and MU were measured using a precise analytical balance. Statistical analysis included two-way ANOVA, Tukey's, and Dunnett's test (α = 0.05). RESULTS: A higher HP concentration was observed with PO+ with the Helical mixing tip in comparison with AM+ (p = 0.01). No significant differences in CC or MU were found for different mixing tips (p = 0.001). The T-mixer mixing tip resulted in significantly less MW (p < 0.00001) and improved mixture homogeneity and viscosity. CONCLUSIONS: Utilizing a T-mixer with self-mixing bleaching gels achieves comparable CC while reducing MW. Moreover, it decreases HP penetration when using PO+. CLINICAL SIGNIFICANCE: For the application of a self-mixing in-office bleaching gel, a T-mixer mixing tip should be recommended, as it reduces the penetration of hydrogen peroxide into the pulp chamber when using PO+, while also minimizing gel wastage.

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.

Evaluating color change and hydrogen peroxide penetration in human and bovine teeth through in-office bleaching procedures.

OBJECTIVE: Assess color alteration and hydrogen peroxide (HP) penetration in human and bovine teeth using various in-office bleaching protocols with different application times. MATERIALS AND METHODS: Thirty healthy human premolars and 30 healthy bovine incisors were divided into five groups and subjected to different bleaching protocols: 2 × 15 min, 1 × 30 min, 2 × 20 min, or 1 × 40 min, with a control group for each tooth type. All teeth were treated with 35% HP gel. Color alteration was measured using digital spectrophotometry before and 1 week after bleaching. HP concentration within the pulp was determined via UV-Vis spectrophotometry. Statistical analysis included one-way ANOVA, Tukey's, and Dunnett's tests (α = 0.05). RESULTS: All groups exhibited significant color alteration, with no statistically differences among them (p > 0.05). However, significant differences were observed when compared with their respective control groups (p < 0.05). HP penetration into the pulp was evident in all bleached teeth compared to the control groups (p < 0.05), with the 2 × 20 group showing the highest HP levels within the pulp cavity, irrespective of tooth type (p < 0.05). CONCLUSION: A simplified 1 × 30-min protocol can be recommended as it effectively maintains color alteration and HP penetration, irrespective of whether human or bovine teeth. CLINICAL SIGNIFICANCE: This study suggests that an in-office dental bleaching protocol using a 1 × 30-min session is recommended, as it ensures both effective color change and no increase in the amount of HP penetration.

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.

Efficacy of a buccal and lingual at-home bleaching protocol-A randomized, split-mouth, single-blind controlled trial.

OBJECTIVE: To compare the color change, the risk and intensity of tooth sensitivity (TS), and gingival irritation (GI) of at-home bleaching applied on the buccal surface only or the buccal and lingual surfaces. MATERIALS AND METHODS: Sixty patients with canines A2 or darker were selected and their superior arches were randomized in two groups: at-home bleaching on the buccal-only or on the buccal and lingual surfaces, with 7.5% hydrogen peroxide, for 1 h daily/2 weeks. The color change was evaluated at baseline, 7, 14 days, and 1 month after bleaching using shade guides scales (ΔSGU) and a spectrophotometer (ΔEAB, ΔE00, and ΔWID). Risk and intensity of TS and GI were recorded daily using visual analogic scale (0-10). Patient satisfaction was evaluated with the orofacial esthetics. Paired t-test, McNemar's, and Wilcoxon signed-rank test were used for data analysis (α = 5%). RESULTS: Neither the color change nor the risk/intensity of TS was statistically different between groups (p > 0.05). Patient satisfaction increased after bleaching for both groups (p < 0.05). CONCLUSION: The addition of one contact surface does not result in an increased whitening degree compared to bleaching applied solely on the buccal surface. CLINICAL SIGNIFICANCE: Understanding the influence of surfaces interacting with the bleaching agent is crucial for comprehending the bleaching mechanism and avoiding unnecessary material expenses. Notably, employing the buccal-only technique is sufficient to achieve the desired efficacy.

Evidence-based fact checking for selective procedures in restorative dentistry.

OBJECTIVES: Similar to other dental specialties, there are many clinical procedures in restorative dentistry that may or may not be supported by good evidence. Thus, the effectiveness of these procedures is uncertain. The aim of this paper is to reduce this knowledge gap by critically inspecting selective procedures in restorative dentistry and exploring if these well-established or widely advocated treatment modalities are necessary for improving treatment outcomes based on the best available evidence. MATERIALS AND METHODS: A MEDLINE search was conducted to identify research on selective procedures while focusing on clinical trials and systematic reviews. Due to their practical relevance in the decision-making process, cost-effectiveness analyses were also included. RESULTS: Mixed results were identified regarding the included interventions. Some procedures had adequate evidence supporting them while others were mostly based on beliefs. CONCLUSIONS: A critical review of the available literature indicates that some common restorative procedures lack adequate support from high-quality research evidence. CLINICAL RELEVANCE: This paper attempts to highlight the need to critically examine the scientific validity of traditional knowledge and techniques through the context of current research evidence. This will not only help generate consensus between educators, clinicians, and researchers regarding restorative procedures but will also lead to improved patient care and outcomes.

Effect of an experimental desensitizing gel on bleaching-induced tooth sensitivity after in-office bleaching-a double-blind, randomized controlled trial.

OBJECTIVES: To evaluate the risk and intensity of tooth sensitivity (TS), and the efficacy of in-office bleaching after applying an experimental desensitizing gel composed of 10% calcium gluconate, 0.1% dexamethasone acetate, 10% potassium nitrate, and 5% glutaraldehyde. MATERIAL AND METHODS: In a split-mouth, double-blind, placebo-controlled study, 50 participants had their upper hemiarches randomized into experimental and placebo groups. Desensitizing and placebo gels were applied for 10 min before in-office bleaching (35% hydrogen peroxide, 1 × 50 min; two bleaching sessions; 1-week interval). TS was recorded immediately after bleaching, 1, 24, and 48 h after each session, with a 0-10 visual analogue scale (VAS) and a five-point numerical rating scale (NRS). The color was recorded in all groups at baseline, 1 week after each session, and 1 month after the end of bleaching using shade guide units (ΔSGUs) and a spectrophotometer (ΔEab, ΔE00, and ΔWID). RESULTS: Most participants (96%) felt some discomfort during treatment regardless of the study group. The odds ratio for pain was 0.65 (95% CI 0.1 to 4.1; p = 1.0). The intensity of TS did not differ between groups (p > 0.31), and it was only 0.34 VAS units lower in the experimental group. A significant color change occurred in both groups regardless of the group. CONCLUSIONS: The desensitizing experimental gel applied before in-office bleaching did not reduce the risk and the intensity of TS and did not affect color change. CLINICAL RELEVANCE: Although the experimental desensitizing agent with varying mechanisms of action did not jeopardize the color change, it did not reduce the risk or intensity of in-office bleaching. CLINICAL TRIAL REGISTRATION NUMBER: RBR-7T7D4D.

Various ways of pre-heating a bulk-fill thermoviscous composite in restoration in non-carious cervical lesions: 12-month randomized clinical trial.

OBJECTIVE: The objective of the study is to evaluate through a randomized clinical trial the best method to preheat a composite resin, if using a Caps dispenser device associated with Caps Warmer (CD) or with a VisCalor Caps dispenser/warmer (VD) for restorations in non-carious cervical lesions (NCCLs). MATERIAL AND METHODS: One hundred and twenty restorations were distributed to two groups (n = 60) according to the pre-heating way of thermoviscous bulk-fill composite resin. For the CD group, pre-heating was carried at 68 °C using a heating bench for 3 min. For the VD group, pre-heating was performed at 68 °C using a heating gun for 30 s. After that, pre-heated bulk-fill composites were directly inserted in the NCCLs. The total working time was recorded. The restorations were evaluated after 6 and 12 months of clinical performance according to the FDI criteria. Statistical analysis was performed using the Student's t test for unpaired samples for working time, and the Chi-square test for restoration clinical performance (α = 0.05). RESULTS: Working time was shorter for VD with a statistically significant difference compared to CD (p = 0.01). Few restorations were lost or fractured after 12 months of clinical evaluation (p > 0.05). The retention rates were 96.7% (CI 95 %: 88.6-99.1%) for CD and 98.3% (CI 95 %: 91.1-99.7%) for VD. The other FDI parameters were considered clinically acceptable. CONCLUSIONS: The different pre-heating ways did not influence the clinical performance of thermoviscous bulk-fill composite restorations in NCCLs after 12 months. CLINICAL RELEVANCE: Regardless of the bulk-fill thermoviscous composite resin pre-heating ways, the restorations are clinically acceptable after 12 months.

Can all highly concentrated in-office bleaching gels be used as a single-application?

OBJECTIVE: This in vitro study aims to evaluate of hydrogen peroxide (HP) diffusion into the pulp chamber, bleaching efficacy (BE), and pH stability (pH) of single-application high concentrated in-office bleaching gels. MATERIALS AND METHODS: Eighty-eight healthy premolars were randomly into eleven groups (n = 8) according to the in-office dental bleaching: DSP White Clinic 35% calcium (DW), Nano White 35% (NW), Opalescence XTra Boost 40% (OB), Pola Office + 37.5% (PO), Potenza Bianco Pro SS 38% (PB), Total Blanc 35% (TB), Total Blanc One-Step 35% (TO), Whiteness Automixx 35% (WA), Whiteness Automixx Plus 35% (WP), and Whiteness HP Blue 35% (WB). A group not exposed to bleaching agents was the control group (CG). All bleaching agents were applied in one session with a single application. After the bleaching procedure, the concentration of HP diffusion (µg/mL) into the pulp chamber was assessed using UV-Vis spectrophotometry. The BE (ΔEab and ΔE00) was evaluated before and 1 week after the bleaching procedure using a digital spectrophotometer. The pH of each bleaching gel was evaluated by digital pHmeter. The one-way ANOVA and Tukey's was used for a statistical analysis (α = 0.05). RESULTS: The concentration of HP diffusion into the pulp chamber was higher in all in-office bleaching gels when compared to CG (p < 0.0000001). However, there are a significant difference between them (p = 0.0001). A significant BE was observed in all in-office bleaching gels (p < 0.0001 for ΔEab and ΔE00), with a significant difference between them (p < 0.0001). PO, OB, TB, WP, and WB showed a higher BE when compared to DW, PB, and WA (p < 0.0001). Most bleaching gels were slightly acidic or alkaline during the total application time, while DW, PB, TB, and WA showed a high acidic behavior after 30 min of application. CONCLUSIONS: A single application was able to produce a bleaching efficacy. However, usually, gels with slightly acidic or alkaline pH during the application time reduces the HP diffusion into the pulp chamber. CLINICAL RELEVANCE: The single-application of bleaching gels with slightly acidic or alkaline and stable pH decreased the penetration of hydrogen peroxide into the pulp chamber in in-office bleaching and maintained the bleaching efficacy.

Effect of irradiance and exposure time on the adhesive properties of universal adhesives after 2 years of storage.

OBJECTIVE: This study aims to evaluate the effects of exposure time and irradiance on the dentin bonding properties (microtensile bond strength (µTBS) and nanoleakage (NL)) of the Clearfil Universal Bond Quick (CUQ) adhesive and Scotchbond Universal Adhesive (SBU) immediately and after 2 years of water storage. MATERIAL AND METHODS: Hence, 128 human molars were randomly assigned to 16 groups based on adhesive strategy, irradiance/exposure times, and storage time for each universal adhesive tested. The adhesives were applied using the etch-and-rinse and self-etch strategies and were light-cured using four different irradiance/exposure times: 1400 mW/cm2 for 5 s (1400 × 5), 1400 mW/cm2 for 10 s (1400 × 10), 3200 mW/cm2 for 5 s (3200 × 5), and 3200 mW/cm2 for 10 s (3200 × 10). Then, each sample was restored and sectioned into a resin-dentin bonded stick to be tested for µTBS and NL (immediately and after 2 years of water storage). The mean µTBS and NL of all resin-dentin bonded sticks from the same hemi-tooth (factor time) were statistically analyzed using a three-way ANOVA and Tukey's test (a = 0.05). RESULTS: Despite a significant decrease in the µTBS values for all groups after 2 years of water storage, the 3200 × 5 group showed higher µTBS values, whereas the 3200 × 10 group showed lower µTBS values for both universal adhesives tested. Although a significant increase in the NL values was observed for all groups after 2 years of water storage, the 3200 × 10 group showed higher NL values than the other groups (p < 0.001). CONCLUSION: Results indicate that light-curing the adhesive layer with 14-16 J/cm2 led to an improvement in the stability of the resin-dentin adhesive interface. A longer exposure time (10 s) coupled with a higher irradiance (3200 mW/cm2) resulted in a greater degree of degradation of the adhesive interface. CLINICAL SIGNIFICANCE: To guarantee better stability of the adhesive interface, clinicians could be preferred a light-cured universal adhesive layer with 14-16 J/cm2. Higher irradiances should be avoided.

Eighteen-month clinical evaluation of a new universal adhesive applied in the "no-waiting" technique: a randomized clinical trial.

OBJECTIVE: The aim of this double-blind, randomized clinical trial was to evaluate the 6- and 18-month clinical performances of a new universal adhesive applied in the "no-waiting" (NW) technique to non-carious cervical lesions (NCCLs) using two evaluation criteria. MATERIALS AND METHODS: One hundred and seventy-six restorations were assigned to four groups according to the adhesive system, adhesive strategy, and application mode: Prime&Bond Active (PB) applied using the etch-and-rinse (ER) and self-etch (SE) strategies with 20 s applications and Clearfil Universal Bond Quick (CQ) applied using the ER and SE strategies with the NW technique. The composite resin restorations were evaluated at baseline and after 6 and 18 months using the World Dental Federation (FDI) and US Public Health Service (USPHS) criteria. The Friedman repeated measures analysis of variance and Wilcoxon test were used for statistical analyses (α = 0.05). RESULTS: No significant differences were observed among any of the groups or criteria after 6 months (p > 0.05). After 18 months, 10 restorations were lost (p > 0.05) (2 with PB-ER [95.5%; 95%CI: 92-100%], 4 with PB-SE [90.9%; 95%CI: 82-98%], 0 with CQ-ER [100%; 95%CI: 92-100%], and 4 with CQ-SE [90.9%; 82-98%]). The restorations performed with the SE strategy showed more marginal discrepancies than those performed with the ER strategy, mainly when the FDI criteria were used (p < 0.05). Those that used the PB-SE showed fewer marginal discrepancies than those that used the CQ-SE (FDI; p < 0.05). A few restorations showed marginal discrepancies after the USPHS analysis (p > 0.05). CONCLUSIONS: The results when using the CQ-SE and -ER strategies with the NW technique were similar to those when using the PB-SE and -ER strategies in standard applications to non-carious cervical lesions after 6 and 18 months of clinical evaluation. CLINICAL RELEVANCE: After 6 and 18 months, the application of Clearfil Universal Bond Quick with the "no-waiting" technique showed similar clinical performance compared to the standard application of Prime & Bond Active applied using the standard application time (20 s). TRIAL REGISTRATION: ClinicalTrials.gov identifier RBR-5f9gps.

Evaluation of application protocol of the 4% hydrogen peroxide for at-home bleaching: A randomized clinical trial.

OBJECTIVE: Few studies evaluated low concentrations of hydrogen peroxide protocols. The aim of this paper was evaluated two application protocols using 4% hydrogen peroxide in at-home bleaching. MATERIALS AND METHODS: Eighty-six patients with upper canines' shade A2 or darker were randomly allocated under two experimental conditions: two daily applications of 1 h each or a 2-h single application. Color change was evaluated using Vita Classical, Vita Bleachedguide, and digital spectrophotometer weekly and 1 month after the bleaching procedure through one-way ANOVA. The risk and intensity of tooth sensitivity (TS) was assessed through visual and numeric rating scale and measured by Fisher's exact test, Mann-Whitney test and one-way ANOVA respectively. RESULTS: After 3 weeks, the mean difference for the ΔSGU Vita Classical (1.0; 95% CI -0.1 to 2.0), ΔEab (0.7; 95% CI -1.4 to 2.8), ΔE00 (0.1; 95% CI -1.4 to 1.6) and Wi (1.8; 95% CI -1.9 to 5.5) presented no difference (p > 0.08). The relative risk for TS was 0.91 (0.72 to 1.14) without significant difference neither in the risk (p = 0.6) nor in the TS intensity for both pain scales (p > 0.65). CONCLUSIONS: The application protocols evaluated (two daily applications of 1 h each or a 2-h single application) for at-home bleaching with 4% hydrogen peroxide did not showed differences in color change and tooth sensitivity. CLINICAL RELEVANCE: Higher amount of active hydrogen peroxide in two daily applications for at-home bleaching neither accelerate bleaching nor increase the risk or intensity of tooth sensibility.

Inflammatory parameters and color alterations of dental bleaching in patients wearing fixed orthodontic appliance: a randomized clinical trial.

BACKGROUND: Many orthodontic patients request dental bleaching during orthodontic treatment to achieve a faster aesthetic resolution, however, no attention has been paid to the inflammatory processes that can occur when both therapies are indicated together. So, this clinical trial evaluated the inflammatory parameters and color alterations associated with dental bleaching in patients wearing a fixed orthodontic appliance. METHODS: Thirty individuals aged between 18 and 40 years were equally and randomly allocated into three groups: FOA (fixed orthodontic appliance), BLE (dental bleaching), and FOA + BLE (fixed orthodontic appliance + dental bleaching). The orthodontic appliances and the bleaching procedures were performed in the maxillary premolars and molars. For dental bleaching a 35% hydrogen peroxide was used. The gingival crevicular fluid (GCF) and nitric oxide (NO-) levels were evaluated at different time-points. Color evaluation was performed using an Easyshade spectrophotometer at baseline (FOA, FOA + BLE, BLE), one month after (FOA + BLE) and 21 days after appliance removing (FOA + BLE and FOA groups), in each tooth bleached. The ANOVA and Tukey's tests, with a significance level of 5%, were used for statistical analysis. RESULTS: The GCF volume in the FOA + BLE and FOA groups significantly increased at the time points evaluated (p < 0.001); however, this did not occur in the BLE group (p > 0.05). On the other hand, NO- levels significantly decreased during dental bleaching with or without fixed orthodontic appliances (FOA + BLE and BLE groups; p < 0.05), while no significant changes were observed in the FOA group (p > 0.05). Significant changes in color were observed in the FOA + BLE and BLE groups compared to in the FOA group (p < 0.01). However, the presence of fixed orthodontic appliance (FOA + BLE) negatively affected the bleaching efficacy compared to BLE group (p < 0.01). CONCLUSIONS: Dental bleaching did not increase the inflammatory parameters in patients wearing fixed orthodontic appliance. However, in the presence of orthodontic appliances, the bleaching efficacy was lower than that of bleaching teeth without orthodontic appliances. TRIAL REGISTRATION: RBR-3sqsh8 (first trial registration: 09/07/2018).

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.

Influence of smoking on oral cells genotoxicity after at-home bleaching using 22% carbamide peroxide: a cohort study.

OBJECTIVE: This study evaluated the influence of smoking on the oral cells genotoxicity before and after at-home bleaching using 22% carbamide peroxide (CP). MATERIALS AND METHODS: This is a prospective observational analytics cohort study which evaluated nonsmokers (NS; n = 24) and smokers (S; n = 16) patients. At-home bleaching was performed using 22% CP gel in individual trays for 1 h per day for 14 days in both groups. Scrapped cells from marginal gums were collected before the bleaching treatment (D0-baseline) and 1 day (D1), 15 days (D15), and 1 month (D30) after its finishing. Cells were stained with Giemsa 10%, and the micronucleus (MN) and metanuclear alterations (MA) were counted by a trained operator in 1000 cells per patient. The collections and data analysis occurred blindly. Data was analyzed by Kruskal-Wallis, Dunn, and Mann-Whitney test (α = 0.05). RESULTS: MN frequency was not influenced by smoking or bleaching. An increase of MA was observed between D0 and D30 for both groups (p < 0.001); however, no statistical difference was found between NS and S (p > 0.05) in the evaluation times. CONCLUSION: Smoking associated with 22% carbamide peroxide gel for at-home bleaching does not show genotoxic potential analyzed by the MN counts. However, a significant increase of MA was found for smokers and nonsmokers. CLINICAL RELEVANCE: Despite of the increase in MA, smoking associated with 22% CP peroxide at-home bleaching showed no important genotoxic potential (MN) for oral cells. Therefore, at-home bleaching treatment is safe for nonsmokers and smokers even with a high carbamide peroxide concentration of 22%.