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Objective: This prospective case series aimed to clinically evaluate the bleaching effect, spontaneous tooth sensitivity and variation in the thermal sensation threshold of different groups of teeth undergoing in-office bleaching., Method and Materials: Ten patients received conventional bleaching treatment: 35% hydrogen peroxide with 3 bleaching sessions of 45 minutes, evaluating color change (ΔE and ΔE00), whitening index (WID), and tooth sensitivity (VAS). Thermal stimulus-generating devices were used to simulate sensitivity caused by low temperatures through Quantitative Sensory Tests (QST). Analyses were conducted individually on different teeth groups (n=20) (lower incisors LI, upper incisors UI, canines C, upper first premolars PM)., Results: Regarding color change, LI and UI did not statistically differ from each other but showed significant difference and greater bleaching potential compared to C and PM (P =.018). Regarding sensitivity, LI and UI presented the highest spontaneous sensitivity values (P =.032), while PM did not display painful symptoms, also observed in provoked sensitivity analysis (P =.025)., Conclusions: The general analysis of the results indicates that the tooth type responds differently to the whitening treatment, both in relation to the aesthetic benefit and the occurrence of tooth sensitivity. It was observed that lower incisors reach the degree of chromatic saturation before canines and premolars, in addition to presenting greater bleaching sensitivity. Personalizing the treatment, based on prior knowledge of the degree of saturation, anatomical factors and the risk of sensitivity, can provide considerable advantages in the whitening technique.

This study aimed to evaluate the interface of universal adhesive (UA) with bulk-fill resin (BF) and dentin, after endodontic irrigation. The pulp chamber of 96 molars was irrigated with chlorhexidine 2% (CHX) or sodium hypochlorite 5.25% (NaOCl) and restored according to three restorative protocols. Microtensile bond strength (μTBS) and nanoleakage tests were performed after 24 h of thermocycling. Kruskal Wallis, Mann-Whitney and Wilcoxon were performed (p < 0.05). Comparing restorative systems, a difference was found only when irrigated with CHX after 24 h. CHX provided higher μTBS than NaOCl after 24 h for two restorative protocols; after thermocycling, NaOCl provided the greatest μTBS than CHX for one group. Decreased μTBS was observed for all restorative systems when CHX was used after thermocycling. NaOCl demonstrated the highest nanoleakage. The composition of UA influenced the immediate adhesion and sealing to BF when CHX was used; ageing has a deteriorating effect on adhesion and sealing for all restorative systems., (© 2024 Australian Society of Endodontology Inc.)

Objectives: This laboratory study evaluated the influence of the fluorescence intensity of composite resins on additional tooth wear and the presence of restorative material in different dental thirds during the retreatment of direct veneers., Materials and Methods: The crown dimensions of 60 bovine incisors were reduced to 10 × 8 mm. The teeth were classified according to the fluorescence intensity of the composites: low (LOW) (TPH Spectra), medium (MED) (Opallis), and high (HIGH) (Essentia) groups. The teeth were divided according to the removal methods: conventional (CON) and fluorescence-aided identification technique (FIT). The specimens were scanned (T0), received veneer preparation, and scanned again (T1). After restorations, the composites were removed and the teeth were scanned (T2). Measurement assessments between T1 and T2 were performed to determine additional wear, presence of residual areas, and the average between additional wear and the presence of residual areas. Kruskal Wallis, Mann-Whitney, Friedman, 2-way ANOVA, and post-Tukey tests were performed (α < 0.05)., Results: The comparison of composite resins indicated a smaller area of additional wear and greater residue presence in the HIGH group than the LOW group for both techniques in the cervical third. Regarding removal methods, the FIT produced greater additional wear than the CON method for the LOW and MED groups in the middle and cervical thirds. The incisal third exhibited greater additional wear than the other thirds., Conclusions: Composite resins with high fluorescence intensity removed using FIT had less tooth wear. The incisal third was the most affected area for direct veneer removal procedures., Clinical Significance: A FIT has been proposed for composite resin removal; however, the different fluorescence intensities of composite resins can influence tooth wear caused during this procedure., (© 2024 Wiley Periodicals LLC.)

The aim of this clinical, prospective, randomized, and parallel study was to evaluate different in-office treatments for dentin hypersensitivity (DH). One hundred ninety-two teeth with non-cavitated root exposures were treated using different desensitizers: fluoride varnish (Duraphat - FLU); bioactive ceramic solution (Biosilicate - BIOS); universal self-etching adhesive (Single Bond Universal - SBU); bioactive photoactivated varnish (PRG filler - SPRG). The degree of DH was analyzed using a visual analog scale (VAS) and computerized visual scale (CoVAS), before treatments and after 7, 15, and 30 days from the first session. Comparisons among desensitizers were performed using the Kruskal-Wallis and Dunn's tests. Friedman test was used to compare between times (p ≤ 0.05). Comparing desensitizers FLU presented a higher value of DH than BIOS using VAS at 7 days, however, no differences were found using CoVAS analysis. Comparing times, BIOS and SBU showed a reduction in DH after 7 days and SBU showed a reduction at 30 days compared to 7 days using VAS. FLU and SPRG groups reduced DH from 15 days to 30 days using VAS. There was a reduction in DH for FLU, BIOS, and SBU after 7 days and for BIOS this reduction also occurred at 30 days when compared to 15 days using CoVAS. SPRG group showed a reduction from 15 to 30 days. All desensitizers tested were able to reduce the initial sensitivity. The bioactive ceramic solution reduced the DH gradually after 30 days using computerized analysis.

Background: Although several studies indicate the harmful effects of bleaching on pulp tissue, the demand for this procedure using high concentrations of hydrogen peroxide (HP) is high., Objectives: To investigate the influence of bleaching on the pulp tissue., Methods: Electronic searches were conducted (PubMed/MEDLINE, Scopus, Cochrane Library and grey literature) until February 2021. Only in vivo studies that evaluated the effects of HP and/or carbamide peroxide (CP) bleaching gels on the inflammatory response in the pulp tissue compared with a non-bleached group were included. Risk of bias was performed according to a modified Methodological Index for Non-Randomized Studies scale for human studies and the Systematic Review Centre for Laboratory Animal Experimentation's RoB tool for animal studies. Meta-analysis was unfeasible., Results: Of the 1311 studies, 30 were eligible. Of these, 18 studies evaluated the inflammatory response in animal models. All these studies reported a moderate-to-strong inflammatory response in the superficial regions of pulp, characterized by cell disorganization and necrotic areas, particularly during the initial periods following exposure to 35%-38% HP, for 30-40 min. In the evaluation of human teeth across 11 studies, seven investigated inflammatory responses, with five observing significant inflammation in the pulp of bleached teeth. In terms of tertiary dentine deposition, 11 out of 12 studies noted its occurrence after bleaching with 35%-38% HP in long-term assessments. Additionally, three studies reported significant levels of osteocalcin/osteopontin at 2 or 10 days post-treatment. Other studies indicated an increase in pro-inflammatory cytokines ranging from immediately up to 10 days after bleaching. Studies using humans' teeth had a low risk of bias, whereas animal studies had a high risk of bias., Discussion: Despite the heterogeneity in bleaching protocols among studies, High-concentrations of HP shows the potential to induce significant pulp damage., Conclusions: High-concentrations of bleaching gel increases inflammatory response and necrosis in the pulp tissue at short periods after bleaching, mainly in rat molars and in human incisors, in addition to greater hard tissue deposition over time. However, further well-described histological studies with long-term follow-up are encouraged due to the methodological limitations of these studies., Registration: PROSPERO (CRD42021230937)., (© 2024 British Endodontic Society. Published by John Wiley & Sons Ltd.)

Objective: To assess whether bleaching gel volume influences chromatic changes, hydrogen peroxide (HP) diffusion, inflammation, and oxidative stress in the pulp tissue., Methodology: A total of 60 bovine teeth were divided into four groups, according to bleaching gel volume (n=15): without gel (WG); V30 (30 µL of 35% HP); V60 (60 µL); and V120 (120 μL). HP diffusion analysis was performed in the first session (T1). Chromatic changes (ΔE, ΔE00, and WID) were assessed after the first (T1), second (T2), third (T3) sessions, and 15 d (T4) after the end of treatment. Moreover, 20 rats were randomly divided into four groups (n=10) and their upper first molars were treated with different gel volumes: control (no treatment); V2 (2 μL of 17.5% HP); V4 (4 μL); and V8 (8 μL). After 24 h, rats were euthanized and the specimens processed for histological and immunohistochemical (nitric oxide synthase) evaluation. Data were analyzed using the Wilcoxon and Mann-Whitney tests (p<0.05)., Results: In vitro (bovine teeth), chromatic changes were not influenced by bleaching gel volume, showing similar values in all groups and sessions, except for the control group (p<0.05). The V120 group had the highest HP diffusion values (p<0.05). In vivo (pulp tissue), the V4 and V8 groups showed the highest inflammatory infiltrate in the pulp and significant oxidative stress (p<0.05)., Conclusion: The adverse effects on the dental pulp related to HP diffusion, pulp inflammation, and oxidative stress depend on bleaching gel volume, while the bleaching effect is not proportional to the volume used.

Objectives: To evaluate in vitro the effects of sodium fluoride (F) and nano-sized sodium trimetaphosphate (TMPnano) added to a 35% hydrogen peroxide (H 2 O 2 ) bleaching gel on the color alteration, enamel mechanical and morphological properties, and H 2 O 2 transamelodentinal diffusion., Materials and Methods: Bovine enamel/dentin discs (n = 180) were divided according to the bleaching gel: 35% H 2 O 2 (HP); 35% H 2 O 2  + 0.1% F (HP/F); 35% H 2 O 2  + 1% TMPnano (HP/TMPnano); 35% H 2 O 2  + 0.1% F + 1% TMPnano (HP/F/TMPnano) and 35% H 2 O 2  + 2% calcium gluconate (HP/Ca). The gels were applied 3 times by 40 min; once each 7-day. The Commission Internationale de l'Eclairage (CIE) L*a*b* total color alteration (ΔE), color alteration by CIEDE2000 (ΔE 00 ), whitening index (ΔWI D ), surface (SH) and cross-sectional hardness (ΔKHN), surface roughness (Ra), and transamelodentinal diffusion were determined. Enamel surfaces were evaluated by Scanning Electron Microscopy (SEM) and X-ray Dispersive Energy (EDX). Data were submitted to ANOVA, followed by the Student-Newman-Keuls test (p <0.05)., Results: ΔE, ΔE 00 , and ΔWID were similar among the gels that promoted a bleaching effect after treatment (p <0.001). Mineral loss (SH and ΔKHN), Ra, and H 2 O 2 diffusion were lower for HP/F/TMPnano; the HP and HP/Ca groups presented the highest values (p <0.001). For SEM/EDX, surface changes were observed in all bleached groups, but less intense with TMPnano., Conclusions: Gels containing F/TMPnano do not interfere with the bleaching effect and reduce enamel demineralization, roughness, H 2 O 2 diffusion, and morphological changes., Clinical Relevance: Whitening gels containing F/TMPnano can be used as a new strategy to increase safety and maintain clinical performance., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: The last author holds a patent for a product used in the study, by the National Institute of Industrial Property – INPI/SP, issued on November 05, 2019, under number BR 102,013,006,761–0., (Copyright © 2023. Published by Elsevier Ltd.)

This study aimed to evaluate the influence of dental adhesive color on the chromatic stability and fluorescence intensity of composite resin restorations of different thicknesses. Ninety bovine enamel samples were obtained and restored with resin composite varying thicknesses of restorative material and enamel (1.0 mm enamel and 1.0 mm composite; 1.5 mm enamel and 0.5 mm composite; 0.5 mm enamel and 1.5 mm composite). The restorations were made of composite resin (Opallis E-bleach H) using different types of dental adhesives: Ambar, Ambar APS, and Single Bond Universal (n=10). The samples were subjected to color measurement tests in a spectrophotometer using CIEDE2000 and fluorescence intensity measurements before and after aging in a red wine coloring solution. Data were subjected to analysis of variance (ANOVA) and Tukey's test (α = 0.05). There were no statistically significant changes in color stability or fluorescence intensity for restorations made of different materials or thicknesses (p>0.05). Single Bond Universal showed greater color stability at 0.5 mm thickness (ΔE00 = 4.4 ± 1.6) compared to other thicknesses of the same material (p=0.003), as well as a greater difference in fluorescence intensity after aging at 1.5 mm thickness (-414.9 ± 103.8) compared to other materials (p=0.0002). Overall, it was concluded that the different adhesive systems did not influence the color stability and fluorescence of restorations of different thicknesses.

Purpose: This in vitro study aimed to evaluate the aesthetic compromise generated in adhesive interface of ceramic laminate veneer luted after tooth bleaching and the use of antioxidant agents. Thus, the chromatic coordinates and whitening index (WI D ) were evaluated, comparing whiteness changes (ΔWI D ) results to perceptibility and acceptability thresholds., Material and Methods: In total, 88 bovine enamel samples (7 × 8 × 4 mm; n = 8) were submitted to the ceramic laminate veneer luting protocol according to surface treatment (unbleached and bleached enamel), antioxidant agents (control; 10% ascorbic acid and 10% α-tocopherol), and luting periods (after 24 h and after 14 days). To lute IPS e.max ceramic restorations (7 × 8 × 0.6 mm), Tetric N-Bond Universal adhesive system and Variolink Aesthetic LC resin cement were used. An ultraviolet-visible spectrophotometer (UV-VIS) was utilized to measure CIE L*a*b* coordinates prior to and after UV-B artificial accelerated aging for 252, 504, and 756 h. L*, a*, and b* axes were evaluated separately, and the whitening stability (ΔWI D ) effect was assessed by varying the whiteness index for dentistry (WI D ). The 50:50% visual threshold was used to evaluate ΔWI D values (whiteness perceptibility [WPT] and whiteness acceptability [WAT]). Color parameters changes (ΔL*Δa*Δb*), WI D, and ΔWI D data were subjected to 2-way repeated measures ANOVA followed by Tukey's test (α = 0.05)., Results: Different UV-aging periods influenced the chromatic coordinates, WI D, and ΔWI D of the ceramic restorations regardless of the bleaching treatment, antioxidant solutions and luting periods (P < .05). In general, ΔWI D values after UV-aging periods were above perceptibility and acceptability thresholds (WPT = 0.72 and WAT = 2.62, respectively) for all experimental groups (P < .05). Unbleached and 10% ascorbic acid-treated enamels luted after 14 days of the antioxidant action exhibited lower ΔL* and Δb* values, while control group showed lower Δa* values. All experimental groups showed similar performance on ΔWI D compared to the control group, regardless of the UV-aging period analyzed (P > .05)., Conclusion: α-tocopherol is a suitable antioxidant solution to be used 24 h post enamel bleaching not compromising clinical acceptability of ceramic laminate veneers., Clinical Relevance: The adhesive interface of ceramic laminate veneers may appear darker after the use of antioxidant agents affecting the clinical acceptability of the restorations., Competing Interests: Declaration of competing interest There are no conflicts of interest to declare., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Purpose: This study evaluates the effects of different toothpastes on the nanohardness and chemical compositions of restorative materials and dental surfaces., Methods: Bovine enamel ( n = 72) and dentin ( n = 72) blocks were obtained and restored using RMGIC ( n = 36) or CR ( n = 36) to create the following surfaces: dentin adjacent to RMGIC (DRMGIC), enamel adjacent to RMGIC (ERMGIC), dentin adjacent to CR (DCR), and enamel adjacent to CR (ECR). After restoration, one hemiface of each specimen was coated with an acid-resistant varnish to facilitate the creation of control (C) and eroded (E) sides; the latter were achieved by erosion-abrasion cycles as follows: erosion with 1% citric acid: 5 days, four times for 2 min each day; 1% citric acid/abrasion, two times for 15 s, followed by immersion in a toothpaste slurry for 2 min. Toothpastes without fluoride (WF; n = 12), with sodium fluoride (NaF; n = 12), and with stannous fluoride (SnF 2 ; n = 12) were used for RMGIC or CR. The specimens were analyzed for nanohardness (H), and chemical composition using energy-dispersive X-ray spectroscopy and Raman microscopy. The data were statistically analyzed using two-way repeated measures ANOVA and Tukey's test (α = 0.05)., Results: Lower H values were obtained with NaF for DRMGIC-C, with a statistically significant difference from the H value obtained with WF ( p < 0.05). The calcium and phosphorus concentrations in DCR-E were significantly lower with WF than with the other types of toothpaste ( p < 0.05). Fluoride-containing toothpastes are capable of preserving the main chemical components of the dentin adjacent to the restorative materials under erosive-abrasive conditions.

Purpose: Few studies have evaluated the influence of antioxidant agents on the optical and mechanical properties of ceramic laminate veneers after dental bleaching. Thus, this in vitro study aimed to evaluate the influence of antioxidant agents on the color stability and mechanical properties, such as nanohardness (HIT), elastic modulus (Eit*), and degree of conversion (DC) of the bonding interface components after dental bleaching in ceramic laminate veneer luting., Methods and Materials: A total of 143 bovine teeth were distributed into experimental groups, according to the procedure method (unbleached or bleached with Whiteness HP Maxx 35%), antioxidant type (control, 10% ascorbic acid, or 10% α-tocopherol), and luting period (24 hours or 14 days) (n=13). The Tetric N-Bond Universal adhesive system and Variolink Esthetic LC resin cement were used as luting agents to lute IPS e.max ceramic restorations (0.6 mm in thickness) to enamel. A UV-visible spectrophotometer was used to assess color stability before and after UV-B artificial accelerated aging for 252, 504, and 756 hours (n=8). The HIT and Eit* of the adhesive and resin cement were measured using a nanohardness tester under a load of 1000 μN, and the DC was measured using a micro-Raman spectrometer (n=5). The color stability and mechanical properties were measured and evaluated by twoway and one-way ANOVA, respectively, and Tukey test (α=0.05)., Results: Distinct aging periods exerted significant changes on the color stability of the restorations luted in enamel associated with ascorbic acid, bleached and unbleached, and the bleached enamel under no antioxidant agent action, for the experimental groups evaluated after 14 days (p<0.05). The use of the α-tocopherol antioxidant solution after the bleaching process for 24 hours did not alter the optical and mechanical properties of the adhesive interface of the laminate restorations compared to those of the control group (p>0.05)., Conclusion: The use of a 10% α-tocopherol antioxidant solution produced promising results, suggesting that it could be mediately used after tooth bleaching to lute ceramic laminate veneers., (©Operative Dentistry, 2023.)

Purpose: The structural integrity of the resin cement layer, the bond strength, and the biomechanical behavior of different fiberglass post cementation techniques were evaluated., Methods: Thirty-three bovine incisors were divided into three groups (n = 11): conventional fiberglass post (CFP), conventional fiberglass post in flared root canals (CFL), and relined fiberglass post (RFP). Six specimens from each group were submitted for high-resolution microcomputed tomography (μCT) to evaluate the integrity and presence/volume of voids at the resin cement layer. Finite element analysis (FEA) of two three-dimensional (3D) models of each group were conducted, one considered ideal (without interface defects) and another containing the conditions identified in the μCT analysis. Push-out bond strength tests were conducted for all specimens., Results: The CFL group had the greatest mean values of void (Thirds cervical: 73.67; middle: 95.67; apical: 47.33) and gap concentration (Thirds cervical: 14.67; middle: 15.83; apical: 8.33) compared with CFP and RFP. A significant difference in bond strength was observed between the cervical (1.33 MPa) and middle thirds (1.85 MPa) compared with the apical third (4.85 MPa) of the CFL. A significant difference was observed in the bond strength in the CFL (1.33 MPa) and RFP (3.29 MPa) in the cervical third, which were statistically similar to the bond strength of the CFP. The tensile stress distributions were similar in most structures, localized in the cervical region on the lingual surface., Conclusions: Structural defects in the interface layer might influence the bond strength and biomechanical behavior under the different fiberglass post cementations.

Objectives: This in vitro study aimed to evaluate the effect of different times and concentrations of hydrofluoric acid etching on the surface of indirect restorative materials obtained from blocks used in CAD-CAM technology., Methods: Specimens (4 mm × 4 mm × 0.8 mm) were obtained for each indirect restorative material: zirconia-reinforced lithium monosilicate ceramic (Celtra Duo), nanoceramic resin (Lava Ultimate), and polymer-infiltrated ceramic network material (Vita Enamic). The materials were submitted to etching with 5% or 10% hydrofluoric acid for 20, 40, 60, or 90 s. A control group for each material was evaluated without any surface treatment, totaling nine experimental groups for each material (n = 10). The specimens were evaluated for surface roughness (R a and R z ), confocal optical microscopy, the contact angle (θ), surface free energy (γs), total free interaction energy (∆G) using a goniometer, and microshear bond strength to resin cement. Specimen images were obtained using scanning electron microscopy, confocal optical microscopy, and atomic force microscopy. Data on the surface roughness, the contact angle, surface free energy, total free interaction energy, and bond strength were subjected to two-way ANOVA and Tukey´s test (α=0.05)., Results: In general, Celtra Duo showed better results after etching with 10% hydrofluoric acid for 40 or 60 s. Lava Ultimate showed better performance after etching with 10% hydrofluoric acid for 20 or 40 s, whereas Vita Enamic showed better results after etching with 5% hydrofluoric acid for 90 s., Conclusion: Each material showed different characteristics after etching with hydrofluoric acid. Knowledge of the proper protocol for each material is essential to ensure improvements in the adhesion process and durability of indirect restorations. In general, Celtra Duo presented mechanical properties superior to those of Lava Ultimate and Vita Enamic., Clinical Significance: Specific etching protocols must be recommended for each indirect material because longer exposure to hydrofluoric acid can jeopardize the surface, thus affecting the mechanical and bond strength properties., Competing Interests: Declaration of Competing Interest The authors have stated explicitly that there are no conflicts of interest in connection with this article., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Objective: The study aims to assess the effects of a 10% H 2 O 2 bleaching gel with different MnO 2 concentrations on the bleaching efficacy (BE), degradation kinetics (DK) of H 2 O 2 , and trans-amelodentinal cytotoxicity (TC)., Materials and Methods: Standardized bovine enamel/dentin disks (n = 96) were placed in artificial pulp chambers, and the bleaching gels were applied for 45 min. Thus, the following groups were established: (G1) no treatment (negative control/NC); (G2) 35% H 2 O 2 (positive control/PC); (G3) 10% H 2 O 2 ; (G4) 10% H 2 O 2  + 2 mg/mL MnO 2 ; (G5) 10% H 2 O 2  + 6 mg/mL MnO 2 ; and (G6) 10% H 2 O 2  + 10 mg/mL MnO 2 . After analyzing bleaching efficacy (ΔE 00 and ΔWI), the degradation kinetics of H 2 O 2 and trans-amelodentinal cytotoxicity were determined (n = 8, ANOVA/Tukey; p < 0.05)., Results: G6 presented BE (ΔE 00 and ΔWI) statistically similar to G2, which represented conventional in-office bleaching (p = 0.6795; p > 0.9999). A significant reduction in the diffusion of H 2 O 2 occurred in G3, G4, G5, and G6 compared to G2 (p < 0.0001). The highest DK of H 2 O 2 occurred in G6 (p < 0.0001), which had the lowest TC in comparison with all other bleached groups (p ≤ 0.0186)., Conclusion: The addition of 10 mg/mL of MnO 2 in a 10% H 2 O 2 bleaching gel potentiates the degradation of this reactive molecule, which increases the BE of the product and decreases TC., Clinical Significance: Replacing a 35% H 2 O 2 gel commonly used for conventional in-office dental bleaching by a 10% H 2 O 2 gel containing 10 mg/mL of MnO 2 reduces the cytotoxicity of this professional therapy, maintaining its excellent esthetic efficacy., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This study aims to evaluate in vitro the effect of violet LED when applied directly to dentin tissue pigmented by different substances. We analyzed the chromatic alteration, the bleaching effect and the temperature variation. Hence, 60 bovine dentin tissue discs were divided into five groups: NNatural Pigmentation; T-Black Tea; C-Soluble Coffee; W-Red Wine; B-Equine Blood. Individualized pigmentation protocols were performed and all groups reached the same chromatic change value. Subsequently, we simultaneously performed a bleaching session and measured temperature variation using a K-type thermocouple device. Data on chromatic change (∆E, ∆E00, ∆a, ∆b and ∆L), whitening effect (WID) and temperature variation were subjected to one-way Anova and Tukey's post-test at a 5% significance level. The C group showed the most relevant chromatic change values, similar to the N group, responding positively to the treatment. However, the B group differed from the control group, which showed difficulty to respond to the treatment. Regarding the whitening index, only the W group showed lower results than the others. The B group showed the greatest temperature changes. We conclude that the violet LED offered chromatic change, which generated a bleaching effect. Pigmentations with red wine and blood showed the greatest difficulty to respond to treatment, also promoting a higher temperature rise in teeth pigmented with blood., Competing Interests: Declaration of Competing Interest The authors declare that there are no conflicts of interest regarding the publication of this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Purpose: This in vitro study aimed to determine the effect of antioxidant solutions used after dental bleaching on the shear bond strength and adhesive interface sealing of ceramic laminate veneer luting. Additionally, effects on the enamel surface characteristics of hydrogen peroxide neutralization, surface energy, total free interaction energy, morphology, and chemical composition of enamel were assessed., Material and Methods: Total 127 bovine incisors were divided into experimental groups, according to the surface treatment (unbleached and bleached enamel), antioxidant types (control; 10% ascorbic acid and 10% α-tocopherol), and periods of luting of ceramic laminates (24 h and after 14 days). Shear bond strength was assessed using microtensile test before and after thermal cycling (5760 cycles, 5-55 °C) (n = 6). The sealing of the adhesive interface was assessed using a confocal laser scanning microscope (n = 3). Hydrogen peroxide neutralization analysis was performed using a spectrophotometer (n = 5). The surface energy and total free interaction energy (n = 10) were measured using an automatic goniometer, while enamel morphology and chemical composition were assessed by scanning eletron microscopy (n = 3). Shear bond strength and enamel surface properties data were subjected to ANOVA followed by Tukey's test (α = 0.05). Adhesive interface micrographs were evaluated by the inter-examiner Kappa test and subjected to Kruskal-Wallis and Dunn's tests (α = 0.05)., Results: In general, thermal aging decreased the shear bond strength values of the luting agents to enamel (P < .05). The α-tocopherol solution was able to reverse the oxidizing effect from dental bleaching, increasing the shear bond strength values and preserving the integrity of the adhesive interface sealing (P < .05). Moreover, the α-tocopherol antioxidant agent promoted higher hydrogen peroxide neutralization after dental bleaching (P < .05). Dental bleaching influenced the enamel surface, decreasing the surface energy and total free interaction energy values (P < .05)., Conclusion: α-tocopherol was able to reverse the oxidizing effects of dental bleaching, improving the enamel surface properties, as well as the adhesion and interface sealing of ceramic laminate veneer restorations., (Copyright © 2022. Published by Elsevier Ltd.)

Objectives: To evaluate the influence of violet LED, associated or not with a 17.5% hydrogen peroxide (HP) bleaching gel, on inflammation, mineralization in pulp tissue, and collagen fiber maturation in dentin and pulp tissue., Materials and Methods: The maxillary molars of eighty Wistar rats were distributed into four groups (n = 10): CONT - without treatment; HP - 30 min application of 17.5% HP; LED - 20 min application of violet LED; and HP+LED - application of PH and violet LED. Rats were euthanized and jaws were processed for histologic and immunohistochemical evaluation (IL-17, IL-23, and osteocalcin) and picrosirius red immediately after (T0), and at 7 (T1), 15 (T2), and 30 days (T3) post-treatment, with Wilcoxon, Mann-Whitney, paired T-test, and T-test (α = 0.05)., Results: HP and HP+LED presented necrosis and severe inflammatory infiltrate. When compared to CONT group, LED presented severe osteocalcin (OCN) immunostaining in T2 and less immature fibers in T2 and T3., Conclusion: The violet LED caused no severe damage to the pulp tissue, increased IL-17 and IL-23 expression in T0 when associated with HP, and had no influence on pulp tissue mineralization, besides accelerating the maturation of collagen fibers of dentin., Clinical Relevance: Violet LED therapy induced no inflammation in the pulp tissue of rats and played no role in pulp tissue fibrosis, besides accelerating the maturation of dentin collagen fibers., Competing Interests: Declaration of Competing Interest The authors declare that there are no conflicts of interest regarding the publication of this paper, (Copyright © 2022. Published by Elsevier B.V.)

Objective: This study evaluated in vitro the effects of calcium gluconate (CaGlu), sodium fluoride (NaF), sodium hexametaphosphate (HMP), and NaF/TMP added to a 35% hydrogen peroxide (H 2 O 2 ) bleaching gel on the color change, enamel hardness, and trans-amelodentinal diffusion., Materials and Methods: Enamel discs/bovine dentin (n = 150) were divided according to the bleaching gel: 35% H 2 O 2 (H 2 O 2 ); 35% H 2 O 2  + 0.1% NaF (H 2 O 2 /NaF); 35% H 2 O 2  + 1% HMP (H 2 O 2 /HMP); 35% H 2 O 2  + 0.1% NaF + 1% HMP (H 2 O 2 /NaF/HMP), and 35% H 2 O 2  + 2% CaGlu (H 2 O 2 /Caglu). The bleaching gels were applied three times (40 min/session) at 7-day intervals between each application. Then, color alteration (ΔE), whitening index (ΔWI D ), percentage of surface hardness loss (% SH), cross-sectional hardness (ΔKHN), and trans-amelodentinal diffusion were determined. Data were submitted for analysis of variance (ANOVA), followed by the Student-Newman-Keuls test (p < 0.05)., Results: All bleaching gels showed significant color changes after treatment (p < 0.001). ΔE and ΔWI D were similar among the evaluated gels. Mineral loss (% SH and ΔKHN) and trans-amelodentinal diffusion of hydrogen peroxide were lower for H 2 O 2 /NaF/HMP; the H 2 O 2 /CaGlu group presented the highest values about the other groups (p < 0.001)., Conclusion: It is possible to conclude that the addition of NaF/HMP to the in-office bleaching agent did not interfere with the bleaching efficacy and reduced enamel demineralization and H 2 O 2 diffusion., Clinical Significance: The association of NaF/HMP to the bleaching gel can be used as a novel approach for minimizing the adverse effects of H 2 O 2 by-products and with similar clinical efficacy., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: Evaluate in vitro the esthetic efficacy and cytotoxicity of a bleaching gel containing 35% hydrogen peroxide (BG-35%H 2 O 2 ), applied for different time intervals, on enamel coated or not with polymeric biomaterials., Materials and Methods: Nanofiber scaffolds (NSc) and a primer catalyst (PrCa) were used to coat the bovine enamel/dentin discs before the application of BG-35%H 2 O 2 , according to the following groups: G1-negative control (NC, without treatment); G2, G3, and G4-BG-35%H 2 O 2 applied for 3 × 15, 2 × 15, and 15 min; G5, G6, and G7-BG-35%H 2 O 2 applied on enamel coated with NSc and PrCa for 3 × 15; 2 × 15, and 15 min, respectively. The culture medium with components of gel diffused through the discs was applied on MDPC-23 cells, which were evaluated regarding to viability (VB), integrity of the membrane (IM), and oxidative stress (OxS). The quantity of H 2 O 2 diffused and esthetic efficacy (ΔE/ΔWI) of the dental tissues were also analyzed (ANOVA/Tukey; p < 0.05)., Results: Only G7 was similar to G1 regarding VB (p > 0.05). The lowest value of H 2 O 2 diffusion occurred in G4 and G7, where the cells exhibited the lowest OxS than G2 (p < 0.05). Despite G5 showing the greatest ΔE regarding other groups (p < 0.05), the esthetic efficacy observed in G7 was similar to G2 (p > 0.05). ΔWI indicated a greater bleaching effect for groups G5, G6, and G7 (p < 0.05)., Conclusion: Coating the dental enamel with polymeric biomaterials reduced the time and the cytotoxicity of BG-35%H 2 O 2 ., Clinical Significance: Coating the dental enamel with polymeric biomaterials allows safer and faster BG-35%H 2 O 2 application., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Statement of Problem: Redesigned mixing tips, promising less impression material waste, have been marketed. However, whether their use adversely affects the dimensional stability and detail reproduction of the impression material is unclear., Purpose: The purpose of this in vitro study was to evaluate the dimensional stability, detail reproduction, and material waste of different polyvinyl siloxane impression materials (regular and light-body) mixed with 2 different mixing tips (MIXPAC T-Mixer mixing tip and MIXPAC helical mixing tip)., Material and Methods: Six different polyvinyl siloxane impression materials were used in 2 different consistencies: Virtual Monophase and Virtual Light Body (Ivoclar Vivadent AG), Express XT Regular and Express XT Light Body (3M ESPE), and Panasil initial contact Regular and Panasil initial contact Light (Kettenbach). The polyvinyl siloxane impression materials were mixed with 2 different mixing tips: conventional helical and T-Mixer (n=10). The specimens were prepared in a metal matrix as per specification #19 of the American National Standards Institute/American Dental Association (ANSI/ADA) and International Organization for Standardization (ISO) 4823:2015. The materials were mixed with both mixing tips as per the manufacturer's instructions, inserted into a perforated custom tray on the matrix, and allowed to polymerize completely. The dimensional stability was calculated based on the measurement of the reproduction of lines engraved in the metal matrix. Detail reproduction was evaluated through analysis of continuity and reproducibility of those lines, immediately, 7 days, and 14 days after polymerization. Material waste was assessed by the difference between the initial (before mixing) and final weight (after complete polymerization) of both mixing tips. The data on dimensional stability and detail reproduction among the materials were submitted to the Kruskal-Wallis test, followed by the Student-Newman-Keuls test (α=.05). Comparison between the mixing tips was carried out with the Mann-Whitney test (α=.05), while the comparison among the periods of analysis (immediate, 7 days, and 14 days) was carried out with the Friedman test (α=.05). The data on material waste between the mixing tips were submitted to 1-way ANOVA, followed by the Tukey honestly significant difference tests (α=.05)., Results: The T-Mixer mixing tip resulted in reduced material waste. For dimensional stability, Virtual Light mixed with T-Mixer resulted in lower dimensional change (0.53 ±0.58%) compared with the helical mixing tip (1.09 ±0.43%). Among the materials, Panasil Light presented higher values of dimensional change at immediate and 7-day analysis when mixed with T-Mixer tip with a statistical difference compared with Express Light, Virtual Light, and Panasil Regular (P<.05). In general, both mixing tips provided similar results in all periods of analysis (P>.05) for qualitative analysis of detail reproduction., Conclusions: The T-Mixer tip resulted in less material waste compared with the helical mixing tip. In general, light-body materials showed higher dimensional stability when the T-Mixer tip was used compared with the conventional tip. In general, reduced detail reproduction was observed after periods longer than 7 days after impression making., (Copyright © 2020 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Objectives: To evaluate the influence of photobiomodulation with infrared laser (IRL) in the rat pulp tissue after bleaching, considering the immunolabeling of interleukin (IL)-23 and hypoxia-inducible factor (HIF)-1α., Methodology: The right and left molars of forty rats were divided into groups: Control - with placebo gel and Bleached - with 35% hydrogen peroxide (H2O2). Half of the rats received one IRL application on both sides, establishing a split-mouth design, which resulted in 4 groups with 20 hemi-maxillae each: Control, Bleach, IRL, and Bleached-IRL. Rats (n=10) from each group were euthanized, at 2- and 30-days mark, and the pulp tissue was evaluated using inflammation and immunolabeling scores. Wilcoxon and Mann-Whitney statistical tests were performed (p<0.05)., Results: At the 2-days mark, the Bleached group had severe inflammation and necrosis in the occlusal thirds of the pulp, and moderate to severe inflammation in cervical third, whereas the Bleached-IRL had mild to moderate inflammation (p<0.05). At the 30-days mark, there was no inflammation, but tertiary dentine formation in the bleached groups. Regarding IL-23, severe immunolabeling was observed in the Bleached group (p<0.05) at the 2-days mark; at the 30-days mark, there was a reduction in immunolabeling, in which the Bleached group had moderate and the Bleached-IRL group had mild immunolabeling (p>0.05). HIF-1α was more evident at the 2-days mark in the Bleached group, without significant difference with the Bleached-IRL (p>0.05). The difference was observed between the bleached and control groups, without immunolabeling (p<0.05); at the 30-days mark, the Bleached group had reduction in HIF-1α immunolabeling, while the Bleached-IRL had an increase; the difference remained between the bleached and the controls groups (p<0.05)., Conclusion: Photobiomodulation using IRL minimized the inflammation and IL-23 immunolabeling in the pulp tissue of rats after dental bleaching, but did not influence significantly the HIF-1α immunolabeling.

Objectives: Although bleaching therapy is considered a dose-dependent treatment, the effect of the volume of product used is yet to be studied. This study thus aimed to evaluate the influence of bleaching gel volume on chromatic alteration and postoperative sensitivity., Methodology: Thirty patients were selected and allocated into three groups; the lower canines were analyzed according to the volume of gel used: GI-0.025 mL, GII-0.05 mL, and GIII-0.10 mL. Chromatic alteration analysis was performed using a portable digital spectrophotometer by calculating the ΔE, ΔE00, ΔL*, Δa*, and Δb* values and the whiteness index (W ID ). Spontaneous sensitivity was assessed using a questionnaire, and sensitivity was stimulated by thermo-sensory analysis. Analyses were conducted in five stages: baseline, after 1st, 2nd, and 3rd bleaching sessions, and 14 days after the end. Data were analyzed using the two-way ANOVA test with repeated measures and Tukey's post hoc test (p < 0.05)., Results: It was observed that ΔE, ΔE00, and ΔL* were similar between groups at the end of the bleaching therapy; and the values of Δa*, Δb*, and WID were higher in the GIII group. For sensitivity, it was found that the GI was the one with the lowest values; o GII intermediate values; while the GIII group presents the highest values of spontaneous and stimulated sensitivity., Conclusion: Gel volume influenced the response to bleaching and significantly influenced the spontaneous sensitivity and cold stimulus., Clinical Relevance: The amount of bleaching gel used during therapy is key to both the response to color change and postoperative sensitivity., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Evaluate the kinetics of hydrogen peroxide (H 2 O 2 ) degradation, esthetic efficacy and cytotoxicity of a bleaching gel with 35%H 2 O 2 applied on enamel previously covered or not with polymeric nanofibrillar scaffold (SNan), polymeric primer catalyst (PPol), and both. Standardized enamel/dentin discs (n = 128) obtained from bovine teeth were adapted to pulp chambers. After covering enamel with the polymeric products, the bleaching gel was applied for 45 min, establishing the following groups: G1: no treatment (negative control); G2: 35%H 2 O 2 (positive control); G3: SNan; G4: PPol; G5: SNan + PPol; G6: SNan + 35%H 2 O 2 ; G7: PPol + 35%H 2 O 2 ; G8: SNan + PPol + 35%H 2 O 2 . The kinetics of H 2 O 2 degradation (n = 8), bleaching efficacy (ΔE/ΔWI; n = 8), trans-amelodentinal cytotoxicity (n = 8), and cell morphology (n = 4) were assessed (ANOVA/Tukey test; p < 0.05). Greater H 2 O 2 degradation occurred in G7 and G8. Bleaching efficacy (ΔE) was higher in G6, G7, and G8 in comparison with G2 (p < 0.05). However, no difference was observed for ΔWI (p > 0.05). G8 presented the lower level of trans-amelodentinal diffusion of H 2 O 2 , oxidative stress, and toxicity to the MDPC-23 cells (p < 0.05). Polymeric biomaterials increased the kinetics of H 2 O 2 decomposition, as well as maintained the esthetic efficacy and minimized the cytotoxicity caused by a bleaching gel with 35%H 2 O 2 . CLINICAL SIGNIFICANCE: Application of a bleaching gel with 35%H 2 O 2 on enamel previously covered by polymeric biomaterials maintains the esthetic efficacy and reduces the cytotoxicity caused by a single session of in-office dental bleaching., (© 2021 Wiley Periodicals LLC.)

Objectives: To evaluate obliterating capability and biological performance of desensitizing agents., Methods: 50 dentin blocks were distributed according to the desensitizing agent used (n = 10): Control (Artificial saliva); Ultra EZ (Ultradent); Desensibilize Nano P (FGM); T5-OH Bioactive Glass (Experimental solution); F18 Bioactive Glass (Experimental solution). Desensitizing treatments were performed for 15 days. In addition, specimens were subjected to acid challenge to simulate oral environment demineralizing conditions. Samples were subjected to permeability analysis before and after desensitizing procedures and acid challenge. Cytotoxicity analysis was performed by using Alamar Blue assay and complemented by total protein quantification by Pierce Bicinchoninic Acid assay at 15 min, 24-h and 48-h time points. Scanning electron microscopy and energy dispersion X-ray spectroscopy were performed for qualitative analysis. Data of dentin permeability was analyzed by two-way repeated measures ANOVA and Tukey's test. For cytotoxicity, Kruskal-Wallis and Newman-Keuls tests., Results: for dentin permeability there was no significant difference among desensitizing agents after treatment, but control group presented highest values (0.131 ± 0.076 Lp). After acid challenge, control group maintained highest values (0.044 ± 0.014 Lp) with significant difference to other groups, except for Desensibilize Nano P (0.037 ± 0.019 Lp). For cytotoxicity, there were no significant differences among groups., Conclusion: Bioglass-based desensitizers caused similar effects to commercially available products, regarding permeability and dentin biological properties., Clinical Significance: There is no gold standard protocol for dentin sensitivity. The study of novel desensitizing agents that can obliterate dentinal tubules in a faster-acting and long-lasting way may help meet this clinical need., (Copyright © 2021. Published by Elsevier Ltd.)

The removal of direct composite veneers, when the retreatment is necessary, represents a challenge to the clinician, since the healthy dental structure must be preserved. Thus, the aim of this study was to compare the accuracy provided by different auxiliary devices during retreatment of direct composite veneers. Seventy-five bovine teeth were prepared for direct composite veneers, scanned (T1), and restored. Specimens were divided into 5 groups for retreatment: conventional high-speed handpiece without auxiliary device (WD); high-speed handpiece with a white LED (WL); high-speed handpiece with an UV light (UL); electric motor and multiplier 1/5 handpiece (EM); and conventional high-speed handpiece using magnifying loupe (ML). After retreatments, other scanning was performed (T2). Changes on dental wear or composite residues areas, as well as, the average between wear and presence of residues were measured. Data were submitted to Kruskal-Wallis and Dunn's post-test (p≤ 0.05). There were greater areas of wear for ML, being statistically superior to WD and EM groups. The ML presented smaller residues areas, being statistically lower than the WD and EM groups. Regarding the average between wear and the presence of resin residues, additional wear occurred after re-preparation, regardless of the group. Magnifying loupe promoted greater areas of wear and smaller areas of resin residues than conventional high-speed handpiece and electric motor. Both techniques using light accessories did not differ from other ones., Competing Interests: The authors have declared that no competing interests exist.

Purpose: To evaluate the microhardness, roughness, profilometry and cross-sectional hardness of single increment materials submitted to different challenges., Methods: Thirty-six disks of each material, Filtek Supreme XTE (FT), Filtek One Bulk Fill (BK), Ketac Molar Easy Mix (KT) and Equia Forte + Coat (EQ) were immersed in saliva, pH cycling and Coke for 15 days. Half of each surface was used as its own control. Superficial microhardness, roughness, perfilometry analysis were performed. All samples were sectioned, embedded in acrylic resins, polished and cross-sectional hardness were made. Data were analyzed by ANOVA and Tukey's test (p < 0.05)., Results: The KT presented superficial microhardness superior than EQ. However, in depth, EQ showed superior values. FT, KT suffered the effects of challenges on microhardness values. The highest roughness and wear values were found for KT. RC do not suffer wear. All materials suffered the effects of Coke and pH challenges in depths 10 µm and 60 µm., Conclusion: The single increment restorative material that suffered less action on its surface was the bulk-fill resin. The coat present in the hybrid ionomer was able to resist to the immersion actions. In addition, Coke was the most aggressive challenge.

Background: The purpose of this study was to investigate the effect of a novel dental bleaching technique with Violet LED on enamel color change, bond strength and hybrid layer nanomechanical properties in resin-dentin restoration, and dentin biostability., Methods: A total of 125 bovine incisors were distributed into a control group, violet LED group (LED), and 35 % peroxide hydrogen bleaching gel (BLG) groups (n = 15). Three 45-minute sessions were performed for both bleaching procedures every week. Enamel color change (ΔE, ΔL, and Δb) was determined after every bleaching session. After color analysis, dentin was exposed for the resin-dentin bond strength analysis using microtensile test and evaluation of the nanomechanical properties at the hybrid layer (nanohardness). While half of the specimens were tested immediately, the remaining were evaluated after 10,000 thermal cycles (TC). Thirty additional teeth were used to investigate dentin ultimate tensile strength (UTS) after the bleaching treatments. UTS was evaluated before and after an enzymatic challenge. Two-way repeated measures ANOVA and Tukey's post-test were used for the statistical analysis (α = 0.05)., Results: Enamel bleaching effect was observed in the LED and BLG groups with significant alterations in the ΔE, ΔL, and Δb in the BLG group. No difference was observed in the resin-dentin bond strength among the groups (p > 0.05), however, TC negatively affected the bond strength values for all the groups. Nanomechanical properties ​​remained unchanged when comparing immediate and after TC results (p > 0.05). Bleaching with BLG reduced significantly the dentin UTS, while all groups showed major decrease in UTS after the enzymatic challenge., Conclusions: Although violet LED was able to promote a bleaching effect, less color changes was observed when compared to BLG. None of the bleaching techniques effected the resin-bond strength or the nanomechanics of the hybrid layer. Violet LED did negatively effect dentin biostability as observed for BLG and it may promote less changes to the organic content of dentin., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Objectives: We evaluated the effects of low-level laser therapy (LLLT) using an infrared laser (IRL) and a red laser (RL) on the pulp of molar teeth in rats after dental bleaching to assess inflammation, collagen fiber maturation, and tertiary dentin formation., Materials and Methods: Eighty Wistar rats (Rattus norvegicus, albinus) were randomly divided into eight groups with 10 hemimaxillae in each of the following: control; bleached (Ble, 35% hydrogen peroxide [H 2 O 2 ]); Ble-1IRL and Ble-1RL (one IRL [808 nm, 30 s, 3 J] or RL [660 nm, 15 s, 1.5 J] application immediately after H 2 O 2 ); Ble-3IRL and Ble-3RL (three [immediately, 24 h, and 48 h] IRL or RL applications after H 2 O 2 ); and 3IRL and 3RL (three IRL or RL applications without bleaching). The rats were euthanized after 2 and 30 days for histological evaluation of inflammation (hematoxylin-eosin) and maturation of collagen fibers (picrosirius red). Additionally, the dentin deposition in the specimens obtained at 30 days was quantified via microtomography of the pulp chamber volume. Statistical analyses were performed (P < 0.05)., Results: Initially, severe damages to the pulp were observed in the Ble and Ble-1RL groups. Ble-1IRL and Ble-3RL groups showed lower inflammation. The bleached groups had a greater amount of mature collagen fibers than the control group. The Ble-3IRL group had a greater number of immature fibers than the Ble group. At 30 days, there was an absence of inflammation and equal proportion of mature and immature collagen fibers. All bleached groups showed a reduction in the volume of the pulp chamber., Conclusion: Three consecutive applications of RL and one IRL application can minimize damage to the pulp of bleached teeth, whereas three IRL applications can minimize pulp fibrosis. However, LLLT did not prevent deposition of tertiary dentin., Clinical Relevance: This study describes LLLT protocols capable of minimizing inflammation and maturation of collagen fibers in pulp tissue after dental bleaching. However, the protocols proved insufficient for reducing the formation of tertiary dentin in bleached teeth.

Clinical Relevance: Pigments in tooth structures affect the diffusion of H2O2 through enamel and dentin. The bleaching methodology can be impacted., Summary: Objective: The aim of this study was to evaluate the influence of the presence of pigments in tooth structures on the trans-enamel and trans-dentin diffusion of hydrogen peroxide (H2O2) and its cytotoxicity after carrying out an in-office bleaching therapy.Methods and Materials: A bleaching gel with 35% H2O2 was applied for 45 minutes (three times for 15 minutes) on enamel and dentin discs (n=6), either previously submitted to the intrinsic pigmentation protocol with a concentrated solution of black tea, or not, defining the following groups: G1, unbleached untreated discs (control 1); G2, unbleached pigmented discs (control 2); G3, bleached untreated discs; G4, bleached pigmented discs. The discs were adapted to artificial pulp chambers, which were placed in wells of 24-well plates containing 1 mL culture medium (Dulbecco's modified Eagle's medium [DMEM]). After applying the bleaching gel on enamel, the extracts (DMEM + components of bleaching gel that diffused through the discs) were collected and then applied on the cultured MDPC-23 odontoblast-like cells. Cell viability (methyl tetrazolium assay and Live & Dead, Calcein AM, and ethidium homodimer-1 [EthD-1] probes), the amount of H2O2 that diffused through enamel and dentin (leuco-crystal violet product), and the H2O2-mediated oxidative cell stress (SOx) and components of degradation were assessed (analysis of variance/Tukey; α=0.05).Results: There was no significant difference between the groups G1 and G2 for all the parameters tested (p>0.05). Reduction in the trans-enamel and trans-dentin diffusion of H2O2 occurred for G4 in comparison with G3. Significantly lower cell viability associated with greater oxidative stress was observed for G3 (p<0.05). Therefore, in-office tooth bleaching therapy performed in pigmented samples caused lower cytotoxic effects compared with untreated samples submitted to the same esthetic procedure (p<0.05).Conclusion: According to the methodology used in this investigation, the authors concluded that the presence of pigments in hard tooth structures decreases the trans-enamel and trans-dentin diffusion of H2O2 and the toxicity to pulp cells of an in-office bleaching gel with 35% H2O2., (©Operative Dentistry, 2020.)

Objective: This study aimed to evaluate the effects of different toothpastes on the surface wear of enamel, dentin, composite resin (CR), and resin-modified glass ionomer cement (RMGIC), and to perform a topographic analysis of the surfaces, based on representative images generated by atomic force microscopy (AFM) after erosion-abrasion cycles., Methodology: One hundred and forty bovine incisors were collected and divided into two groups: 72 enamel and 72 dentin blocks (4×4 mm). Half of the specimens were restored with CR (Filtek Z350 XT) and the other half with RMGIC (Fuji II LC). Then, samples were submitted to a demineralization cycle (5 days, 4×2 min/day, 1% citric acid, pH 3.2) and exposed to three different toothpastes (2×15 s/day): without fluoride (WF, n=12), sodium fluoride-based (NaF, n=12), and stannous fluoride-based (SnF2, n=12). Surface wear, as well as restoration interfaces wear, were investigated by profilometry of the dental substrates and restorative materials. All representative surfaces underwent AFM analysis. Data were analyzed by two-way analysis of variance and Tukey's tests (α=0.05)., Results: NaF-based toothpaste caused the greater dentin surface wear (p<0.05). Toothpastes affected only enamel-restoration interfaces. AFM analysis showed precipitate formation in dentinal tubules caused by the use of fluoride toothpastes., Conclusions: NaF-based toothpastes had no protective effect on enamel adjacent to CR and RMGIC against erosion-abrasion challenges, nor on dentin adjacent to RMGIC material. SnF2-based toothpastes caused more damage to interfaces between enamel and RMGIC.

Purpose: This in vitro study evaluated the effectiveness of polyacrylic acid as an acid etchant similar to phosphoric acid and its effect on the microtensile bond strength of self-adhesive resin cement to enamel., Materials and Methods: Ninety Te-Econom Plus resin blocks (11 x 4 mm) were cemented onto bovine enamel and distributed into 10 groups according to the surface treatments (no surface treatment; etching with 37% phosphoric acid; etching with 20% polyacrylic acid; etching with 37% phosphoric acid + dental adhesive, and etching with 20% polyacrylic acid + dental adhesive) and the self-adhesive resin cements used (RelyX U200 and MaxCem Elite) (n = 9). After bonding, the specimens were sectioned into sticks, subjected to thermocycling (5760 cycles, 5°C and 55°C) and microtensile bond strength testing (n = 6). Images of representative specimens were obtained using a scanning electron microscope. Enamel penetration evaluation of different surface treatments was analysed by confocal laser scanning microscopy (n = 3). Data on bond strength were subjected to 2-way ANOVA and Tukey's least significant difference test (α = 0.05)., Results: Both 37% phosphoric acid and 20% polyacrylic acid yielded the same microtensile bond strength between self-adhesive resin cement and enamel, independent of the application of dental adhesives (p > 0.05). MaxCem Elite showed higher bond strength values than RelyX U200 just for the 20% polyacrylic acid group (p = 0.001)., Conclusion: Acid pre-conditioning of dental enamel may influence the bond strength of self-adhesive resin cement to enamel, and 20% polyacrylic acid showed efficacy similar to that of 37% phosphoric acid.

Objectives: This study evaluated if the use of a bioactive glass-ceramic-based gel, named Biosilicate (BS), before, after or mixed with bleaching gel, could influence the inflammation of the dental pulp tissue of rats' molars undergoing dental bleaching with hydrogen peroxide (H2O2)., Methodology: The upper molars of Wistar rats (Rattus norvegicus, albinus) were divided into Ble: bleached (35% H2O2, 30-min); Ble-BS: bleached and followed by BS-based gel application (20 min); BS-Ble: BS-based gel application and then bleaching; BS/7d-Ble: BS-based gel applications for 7 days and then bleaching; Ble+BS: blend of H2O2 with BS-based gel (1:1, 30-min); and control: placebo gel. After 2 and 30 days (n=10), the rats were euthanized for histological evaluation. The Kruskal-Wallis and Dunn statistical tests were performed (P<0.05)., Results: At 2 days, the Ble and Ble-BS groups had significant alterations in the pulp tissue, with an area of necrosis. The groups with the application of BS-based gel before H2O2 had moderate inflammation and partial disorganization in the occlusal third of the coronary pulp and were significantly different from the Ble in the middle and cervical thirds (P<0.05). The most favorable results were observed in the Ble+BS, which was similar to the control in all thirds of the coronary pulp (P>0.05). At 30 days, the pulp tissue was organized and the bleached groups presented tertiary dentin deposition. The Ble group had the highest deposition of tertiary dentin, followed by the Ble-BS, and both were different from control (P<0.05)., Conclusion: A single BS-based gel application beforehand or BS-based gel blended with a bleaching gel minimize the pulp damage induced by dental bleaching.

Background: To evaluate the bleaching efficacy and post-operative sensitivity of 10 % carbamide peroxide (PC) with or without violet LED (VL)., Methods: Thirty patients were selected and were instructed to perform home bleaching treatment using PC 10 %, for 8 h daily, for 21 days. All patients underwent in-office irradiation of only one hemiarch with VL for 30 min, twice per week for three weeks, totaling six clinical sessions of irradiation. The treatment used for each hemiarch was determined randomly. The analyses were performed at the initial time and 7, 14, and 21 days after the start of treatment and 7 and 14 days after the end of the bleaching treatment. For color analysis, digital spectrophotometry was done using the Visual Analog Scale and cold detection was performed using the thermo-sensory analysis II (TSA II) equipment. The ANOVA-two way with repeated measures and the Tukey test (α = 0.05) were used for the color and cold sensitivity analysis., Results: On analyzing the color change, it was observed that the hemiarch that was irradiated with VL presented the highest values compared with the side that did not receive irradiation. Regarding tooth sensitivity, there was no report of any patient experiencing discomfort during the bleaching protocol. Analysis of the dental thermal sensation threshold showed that the use of VL made the teeth more sensitive., Conclusions: It can be concluded that the VL provided a positive effect on color alteration when used in conjunction with 10 % PC. However, the use of this new protocol made the teeth more sensitive., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Purpose: To evaluate the microtensile bond strength of dentine/self-adhesive resin cement interface after several treatments on a dentine surface., Materials and Methods: Twenty-eight human molars were selected and divided into four groups: no treatment (control (C)); 2% chlorhexidine digluconate (CHX); 25% polyacrylic acid (PA); and 23 ppm dispersive solution of silver nanoparticle (SN). Prepolymerised TPH resin composite (Dentsply) blocks were luted on the dentine surface using RelyX U200 self-adhesive resin cement (3M ESPE). Microtensile bond strength was measured (MPa) in a universal testing machine 24 h and 6 months after the bonding process. The fractured specimens were examined in an optical microscope and classified according to the fracture pattern. A representative sample of each group was observed by scanning electronic microscope. Data were submitted to analysis of variance (ANOVA) and Tukey's test to compare the mean among the groups (p <0.05)., Results: The highest microtensile bond strength values after 24 h were found for the PA group (13.34 ± 6.36 MPa), with no statistically significant difference for the C group (9.76 ± 3.11 Mpa). After 6 months, the highest microtensile bond strength values were found for the C group (9.09 ± 3.27 Mpa), with statistically significant difference only for the CHX group (2.94 ± 1.66 MPa). There was statistically significant difference only for the PA group when comparing the periods studied. Regardless of the surface treatment applied, there were more adhesive failures in both periods of time., Conclusion: Dentinal pretreatment with PA, as well as use of SN before the bonding procedure of self-adhesive resin cement to dentine, may be alternative bonding protocols.

Objectives: MI Paste Plus remineralizer (Rem) strengthens dental structures after bleaching. We investigated the effect of Rem on the penetration of hydrogen peroxide (H 2 O 2 ), bleaching effectiveness, and pulp inflammation after bleaching., Materials and Methods: Bovine disks were grouped as follows (n = 10): control (untreated), bleached (Ble; 35% H 2 O 2 , 30 min), Ble-Rem (H 2 O 2 followed by Rem, 30 min), Rem-Ble (Rem followed by H 2 O 2 ), Rem-Ble-Rem (Rem before and after H 2 O 2 ), and Ble+Rem (mixture of Rem with H 2 O 2 , 1:1, 30 min). The penetration of H 2 O 2 was quantified and bleaching efficacy was analyzed. Upper rat molars (n = 10) received the same treatments at random. The rats were euthanized after two days and 30 days, and their jaws were removed for histological analysis. Statistical tests were performed (P < 0.05)., Results: The bleached groups, except Ble+Rem (P > 0.05), showed significant H 2 O 2 penetration compared with control (P < 0.05). Color alteration analysis showed that ΔL and ΔE were significantly higher in the bleached groups than those in control (P < 0.05); the Δb of the bleached groups differed from that of control at 24 h (P < 0.05). At two days, necrosis or inflammation was observed in the bleached groups compared with control (P < 0.05), except Ble+Rem, which was similar to control (P > 0.05). At 30 days, tertiary dentin formation was significant in the bleached groups (P < 0.05), except Ble+Rem (P > 0.05)., Conclusion: The mixture of MI Paste Plus and bleaching gel reduces H 2 O 2 penetration and pulp damage and maintains bleaching effectiveness., Clinical Relevance: Because bleaching can damage dental tissues, we studied a new bleaching protocol that reduces damage to the pulp tissue while maintaining bleaching efficiency: a single application of 30 min of MI Paste Plus mixed with 35% H 2 O 2 bleaching gel (1:1).

Objectives: To minimize the tooth sensitivity caused by in-office bleaching, many dentists use non-steroidal anti-inflammatory drugs and topical desensitizing gels containing potassium nitrate and sodium fluoride. This study aimed to evaluate the influence of these substances on inflammation and the expression of substance P and calcitonin gene-related peptide in pulp nerve fibers., Materials and Methods: Seventy-two rats were divided into 6 groups as follows: GI, control; GII, only dental bleaching; GIII, only ibuprofen; GIV, ibuprofen administered 30 minutes before and after the bleaching treatment and every 12 hours until the analysis; GV, only topical application of a desensitizing agent; and GVI, topical application of a desensitizing agent before dental bleaching. Placebo gel was applied to the upper left jaw and the bleaching agent was applied to the upper right jaw in all groups. Subsequently, the groups were divided into 3 subgroups based on the time of analysis: 0, 24, and 48 hours after bleaching ( n = 8). The rats were euthanized and the maxillae were processed and evaluated by histopathological and immunohistochemical analyses. The data were analyzed using the Kruskal-Wallis test, followed by the Dunn test ( p < 0.05)., Results: In the bleaching groups, the inflammatory process and expression of neuropeptides decreased over time. The animals in which a desensitizing agent was applied showed better results within 24 hours., Conclusions: The use of a desensitizing agent had positive effects on inflammation and pain-related neuropeptide expression, minimizing the painful effects of dental bleaching treatment., Competing Interests: Conflict of Interest: No potential conflict of interest relevant to this article was reported., (Copyright © 2020. The Korean Academy of Conservative Dentistry.)