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This study evaluated the impact of using calcium hydroxide or antioxidant agents on the bond strength of adhesive restorations to bleached dentin. A total of 40 teeth were prepared and allocated into eight groups, first divided according to the surface treatment after bleaching (no treatment or application of calcium hydroxide, 10% sodium ascorbate, or 5% sodium thiosulfate for 10 minutes) and then according to the time of final restoration after treatment (immediate or after 7 days). Sodium perborate with 20% hydrogen peroxide was applied for 3 weeks using a developed artificial pulp chamber, with peroxide replacements provided every week. Composite resin restoration was performed, followed by a microtensile test. Then, specimens were analyzed using a stereomicroscope and scanning electron microscopy (SEM). Data were submitted to Kruskal-Wallis and Dunn tests (P < .05). The bond strength of nonbleached teeth was similar to the groups restored after 7 days of bleaching (P < .05). The lowest bond strength values were seen in groups restored immediately after bleaching (P < .05). In all groups, there was a considerable predominance of adhesive fractures. Delaying the final restoration of teeth submitted to nonvital bleaching by 7 days increased the bond strength. The immediate restoration of bleached teeth after using 10% sodium ascorbate or 5% sodium thiosulfate for 10 minutes showed unsatisfactory results. Irrespective of the dentin protocol applied before adhesion, bond strength values will be satisfactory when delaying the final restoration and unsatisfactory when immediately performing the final restoration. Therefore, after nonvital tooth bleaching, clinicians should always delay the final restoration for a minimum period of 7 days. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to evaluate the influence of different whitening toothpastes on color change and alteration in enamel surface roughness and microhardness compared to a conventional toothpaste. Method and materials: Fifty bovine incisors were selected, cleaned, and stored before being divided into five groups: a conventional toothpaste group and three whitening toothpaste groups containing different abrasive agents: silica, hydrogen peroxide, and activated charcoal. Specimens underwent simulated brushing, staining with black tea solution, and subsequent analyses of color, surface roughness, and microhardness. Statistical analysis was performed using three-way ANOVA and Tukey post-hoc tests (P < .05). Results: The results showed that the color analysis revealed similar whitening potential among all toothpastes. They showed significant differences in surface roughness (P < .001) and microhardness (P < .001) after simulated brushing. While all toothpastes caused a decrease in microhardness, the charcoal-based toothpaste showed a significant increase in surface roughness compared to the initial condition. Conclusion: All toothpastes demonstrated whitening capability. Surface roughness changed after brushing with activated charcoal-based whitening toothpaste, but final roughness was similar across all groups. Whitening toothpastes led to a decrease in enamel microhardness, with similar final performance across all toothpastes analyzed. [ABSTRACT FROM AUTHOR]

Objective: In the absence of targeted antidotes for chlorine gas poisoning, a common yet concerning problem, this study investigates the effect of Wet Cupping Therapy (WCT, or "Hijamat") on the recovery process in chlorine-induced reactive airway dysfunction syndrome (RADS) patients. Materials and Methods: This randomized controlled trial enrolled 24 patients experiencing acute inhalation of chlorine poisoning in Tehran, Iran (2020-2021). Patients were randomly divided into control (n=12, receiving conventional treatment) and intervention (n=12, receiving conventional treatment plus WCT) groups. Signs and symptoms were assessed pre-intervention, and in the first hour, first week, and first month post-intervention. Results: Medical records of 24 patients, including 3(12.5%) men and 21(87.5%) women, with a mean age of 42.92 years old, were evaluated. Baseline characteristics were similar between the groups. WCT significantly improved symptoms (dyspnea, cough, chest tightness, etc.) within the first hour (p=0.003) compared to the controls, with no future significant changes during the first week and first-month post-WCT. Comparison between the groups revealed substantial differences in the following variables: dyspnea scale (p=0.009), respiratory rate (p=0.026), cough (p=0.001), breath shortness (p=0.006), chest tightness (p=0.002), chest pain (p=0.010), substernal burning (p=0.015), throat sore (p=0.005) and hoarseness (p=0.027). Peak flow meter readings, reflecting lung function, were also significantly higher in the WCT group at all time-points (p<0.007). Conclusion: WCT may offer a rapid and sustained improvement in pulmonary and respiratory symptoms following acute chlorine inhalation injury. [ABSTRACT FROM AUTHOR]

Background: There is an increasing desire for teeth bleching after orthodontic treatment. Therefor, this study aims to evaluate the effect of carbamide peroxide 15% and thermocycling on the compressive strength of polyethylene terephthalate glycol (PETG) thermoplastic retainer material. Materials and Methods: In this in vitro study, forty samples of PETG material were thermoformed over a plastic template (10 mm × 8 mm × 2 mm). The samples were divided into four groups, with ten samples in each group. Group I served as the control, Group II was exposed to carbamide peroxide 15% (5 h daily for 14 days), Group III underwent thermocycling (5000 times), and Group IV underwent thermocycling (5000 times) followed by exposure to carbamide peroxide 15% (5 h daily for 14 days). The compressive strength of the groups was then evaluated using one-way ANOVA and Tukey's HSD tests for statistical analysis. The significance level was set to 0.05. Results: The analysis showed a significant difference among the four groups. The compressive strength of all groups significantly decreased compared to the control group. Group II exhibited a significant decrease compared to Group III (P = 0.003). However, there was no significant difference between Group II and Group IV (P = 0.191). In addition, there was no significant difference observed between Group III and Group IV (P = 0.308). Group II had the lowest compressive strength (163.9 Mpa). Conclusion: It is not recommended to use a thermoplastic retainer as a bleaching tray during the initial phase of retention. However, since there were no further harmful effects of bleaching agents observed after thermocycling, it is possible to recommend the use of a thermoplastic retainer as a bleaching tray toward the end of the retention phase. [ABSTRACT FROM AUTHOR]

Objective The aim of this study was to test the effect of different bleaching protocols on surface roughness, color stability, and translucency parameter of coffee-stained nanohybrid dental composites with different viscosities. Materials and Methods Five nanohybrid dental composites with different viscosities (n = 250)—Neo Spectra LV, Neo Spectra HV, Neo Spectra Flow (Dentsply, Konstanz, Germany), Grandio, and Grandio Flow (Voco, Cuxhaven, Germany)—were used to test surface roughness, color stability, and translucency parameter after bleaching of coffee-stained specimens using either in-office bleaching, home bleaching, or a combination of both. The viscosity of the five types of dental composites was tested using a viscometer. A scanning laser microscope (SLM) was used to examine the surface topography of representative samples from each dental composite after the combined effect of both bleaching agents. Effect of composite type, bleaching protocol, and their interaction was assessed by two-way analysis of variance. For multiple comparisons, Tukey's post hoc test was used with Bonferroni correction. Results Surface roughness of all coffee-stained dental composites increased after bleaching; however, those of Grandio and Grandio Flow increased significantly (p < 0.0001). This was confirmed by SLM images that showed rough surface with protruding fillers after in-office and home bleaching protocol. Results revealed that bleaching, regardless of the protocol, decreased the delta E values of all dental composites; however, it was still higher than the accepted threshold value of 3.7. Neither of the bleaching protocols enhanced translucency parameter of all dental composites. Neo Spectra Flow and Voco Flow had the highest translucency parameter after the three bleaching protocols. Conclusion Bleaching does not improve color stability and translucency of coffee-stained nanohybrid dental composites regardless of the viscosity. Surface roughness of coffee-stained nanohybrid dental composites increases after application of bleaching agents. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effect of reducing exposure time to at-home bleaching gel on color change and tooth sensitivity. Materials and methods: The search was carried out using PubMed, Scopus, Web of Science, EMBASE, LILACS, Cochrane. Randomized clinical trials (RCTs) were included involving adult patients who have never undergone bleaching treatment before (P), subjected to bleaching with a reduced exposure time to the at-home bleaching agent (I) compared to those who used it for the time indicated by the manufacturer (C), to evaluate the effects on color change and tooth sensitivity (O). The Cochrane guidelines for the Risk of Bias Assessment Tool (RoB 2.0) and GRADE were used to assess risk of bias and quality of evidence, respectively. Results: Using at-home bleaching gel for the period recommended by the manufacturer resulted in significantly higher ΔEab and ΔWID values and better subjective color change (ΔSGU—Classical), regardless of the evaluation time. Regarding the post-bleaching evaluation, no significant differences were found for ΔE00 immediately after bleaching or ΔSGU (Bleached) at any time. Reducing the time of use significantly decreased tooth sensitivity events. Conclusions: Reducing exposure time to at-home bleaching gel reduces tooth sensitivity events; however, most of the parameters that assess color change indicate using at-home bleaching gel for the time recommended by the manufacturer. Clinical significance: Reducing exposure time to at-home bleaching gel should be applied with caution in clinical practice. Although the evidence suggests a reduction in tooth sensitivity events, bleaching effectiveness was significantly higher after using the bleaching gel for the time indicated by the manufacturer. [ABSTRACT FROM AUTHOR]

Background. Considering the few studies on the effect of bleaching protocols on the color properties of a newly developed monochromatic universal composite resin, the present study evaluated the effect of different bleaching protocols on the color change and translucency of Omnichroma (OMN) composite resin. Methods. In this laboratory study, 45 cylindrical OMN composite resin disks with a diameter of 10 mm and a thickness of 2 mm were used. The samples were randomly divided into three groups (n=15) based on the bleaching protocols: group 1: 40% hydrogen peroxide (HP) for 20 minutes, twice a day for three sessions one week apart; group 2: 20% carbamide peroxide (CP) for 8 hours a day, for 14 consecutive days; group 3: 40% HP with Nd:YAG laser (HP+Nd:YAG laser) applied on the gel for 30 seconds twice. Baseline and post-bleaching measurements of color parameters were done using a Vita Easyshade spectrophotometer. Data was analyzed using paired-samples t-test, one-way ANOVA, and post hoc Tukey tests (P<0.05). Results. All the bleaching protocols significantly changed the color (P<0.001) and translucency (P<0.001) parameters. CP caused the most color changes (P<0.05) and translucency (P<0.05), which were significant, and color and translucency changes caused by HP and HP+Nd:YAG laser were not significant (P>0.05). Conclusion. Bleaching caused a noticeable change in the color and translucency of the OMN composite resin. The effect of the at-home bleaching protocol was greater than the in-office ones. [ABSTRACT FROM AUTHOR]

ABSTRACT Clinical Significance Objective: This study evaluated the color change, surface roughness, mineral content and morphology of enamel bleached with 35% hydrogen peroxide (HP) combined with an experimental gel containing 1% titanium tetrafluoride (TiF4).Materials and Methods: Bovine enamel blocks were treated with (n = 12): (TiF) experimental gel containing 1% TiF4, (HP) 35% HP, (HPT) 35% HP + 1% TiF4 and (CT) control. Bleaching with HP was performed in 3 sessions (3 × 15 min/applications). pH, colorimetric parameters, surface roughness, mineral content and enamel morphology were determined. The pH was evaluated for 45 min. The color parameters were determined before bleaching (T0), and 14 days elapsed from the last bleaching session (T4). Surface roughness was analyzed at T0 and immediately after last bleaching session (T3). Enamel mineral content and morphology were verified at T4. Data were statistically analyzed by one‐way, two‐way ANOVA and Kruskal–Wallis (α = 0.05).Results: TiF increased surface roughness, and no differences between HP and HPT in terms of color and CO32−$$ {\mathrm{CO}}_3^{2-} $$–PO43−$$ {\mathrm{PO}}_4^{3-} $$ mineral content. Ti was detected only on TiF, and slight surface morphology changes were observed in bleached enamel.Conclusions: The combination of TiF4 and 35% HP did not interfere with the enamel bleaching effect, controlled surface roughness, and kept mineral content but promoted a minor surface morphology alteration.Due to the adverse effects of bleaching, titanium tetrafluoride (TiF4) has gained attention for its therapeutic properties, including the ability to reverse mineral loss and neutralize remineralization of mineral structures. Therefore, TiF4's remineralizing capacity may be a good alternative for incorporation into hydrogen peroxide bleaching agents. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: Peroxide from bleaching agents can cause external cervical resorption. An intracoronal barrier is used to prevent leakage of bleaching agents into the periradicular space. Aim: This study aims to determine and compare the amount of peroxide released, during non vital bleaching at the end of 1st and 3rd day using Glass ionomer cement (GIC), Mineral Trioxide aggregate (ProRoot MTA) and Biodentine as intracoronal barriers. Materials and Methods: Forty-five single-rooted teeth were selected for the study and root canal therapy was performed. Three millimeters of the coronal gutta-percha were removed and according to the coronal barrier placed, samples were divided into Group A: GIC, Group B: ProRoot MTA, and Group C: Biodentine. Nonvital bleaching was done using sodium perborate and 30% H2O2. Peroxide released at the end of the 1st and 3rd day was analyzed using potassium iodide and ultraviolet spectrophotometer. Statistical Analysis: This was done using the Wilcoxon matched pair test and the Kruskal–Wallis test. Results: No significant difference in intergroup comparison at the end of 1st and 3rd day, respectively (P > 0.05), a significant difference was found in the MTA group at follow-up dates (P < 0.05). Conclusion: All the three tested materials (GIC, MTA, and Biodentine) may be preferred as intracoronal barrier for nonvital bleaching. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to investigate the color changes (ΔE) of two different composite resins after staining and bleaching. Material and Methods: A total of 100 specimens were prepared from microhybrid and nanohybrid composites. The samples were divided into five groups and stained for 30 days with tea, coffee, cola, red wine, or distilled water (control). Each group was further divided into two subgroups to receive a 14-day application of Opalescence PF or VivaStyle® Paint On Plus bleaching materials. The color of all samples was determined at baseline, after staining, and after bleaching. Data were analyzed using ANOVA and independent sample t-test. Results: The highest ΔE values were observed in the red wine groups for both composites. Bleaching agents decreased ΔE values; however, they were unable to return the values to baseline values. Conclusion: Staining and bleaching may affect color, depending on the type, filler, and matrix content of the composite resin.

ABSTRACT: Objective: The aim of this study was to investigate the color changes (ΔE) of two different composite resins after staining and bleaching. Material and Methods: A total of 100 specimens were prepared from microhybrid and nanohybrid composites. The samples were divided into five groups and stained for 30 days with tea, coffee, cola, red wine, or distilled water (control). Each group was further divided into two subgroups to receive a 14-day application of Opalescence PF or VivaStyle® Paint On Plus bleaching materials. The color of all samples was determined at baseline, after staining, and after bleaching. Data were analyzed using ANOVA and independent sample t -test. Results: The highest ΔE values were observed in the red wine groups for both composites. Bleaching agents decreased ΔE values; however, they were unable to return the values to baseline values. Conclusion: Staining and bleaching may affect color, depending on the type, filler, and matrix content of the composite resin. [ABSTRACT FROM AUTHOR]

This systematic review examines studies focusing on tooth bleaching and its effects on healthy enamel or incipient caries and bacterial adhesion. The aim is to explore the impact of different bleaching agents on incipient caries lesions and healthy enamel. Clinical studies, in vitro studies, and observational studies that compared at least two groups were included. A search strategy was used to select studies from the MEDLINE via Pubmed and Scopus databases. Two evaluators performed data extraction, screening, and quality assessment independently. Only studies written in English were included. From 968 initial records, 28 studies were selected for a full-text evaluation. Of these, 7 studies were classified as cluster 1 (bacterial adherence on teeth), 12 studies as cluster 2 (no bacteria involved), 4 studies as cluster 3 (no teeth deployment), and 5 clinical studies were cluster 4. Of the selected studies, 6 (21.4%) supported increased bacterial attachment capacity and cariogenic dynamics, 4 (14.3%) decreased adhesion and cariogenic activity, 7 (25%) showed no difference, and 11 (39.3%) followed a different methodological approach and could not be categorized. The risk of bias appeared to be high, mainly because of the different methodologies in the studies, so we cannot reach a confident conclusion. Nevertheless, as far as carbamide peroxide bleaching is concerned, there does not seem to be a clinically significant alteration, neither in microorganism counts nor in enamel microstructure. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the bleaching efficacy, decomposition rate, and pH of experimental gels containing 35% hydrogen peroxide (HP) and different concentrations of 45S5-bioglass (BG) or Biosilicate® (BS). Methods: Bovine enamel/dentin blocks (n=10) were allocated into the groups HP_BG or HP_BS (2.5, 5, 7.5 and 10 wt%) and HP (35% HP - positive control). The blocks were submitted to three sessions of 40 min and 7-day intervals. During the interval, the blocks were kept in artificial saliva at 37°C. Color change (E00) and whiteness index change (WID) were determined after staining with black tea (T1) and 24 h after the 3rd bleaching session (T2). HP decomposition rate (%) and pH were evaluated for 40 min. Two-way ANOVA and Tukey analyzed E00 and WID data, while the Kruskal-Wallis test determined the decomposition rate and pH of the gels. Results: There were no differences in E00 and WID among the experimental bleaching gels containing BG or BS and 35% HP (p > 0.05), but BG and BS gels displayed lower HP concentration than 35% HP, regardless of the bioactive material concentration (p < 0.05). The experimental BG and BS gels exhibited alkaline pH (ranging from 9.28 to 9.82), which was higher than that of 35% HP (p < 0.05). But regardless of the gel, all kept the pH values stable for 40 min. Conclusion: The experimental gels containing BG and BS did not hamper the 35% HP bleaching efficacy. Moreover, BG or BS gels decreased the hydrogen peroxide concentration and exhibited alkaline pH values. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the surface roughness and color stability of bulk-fill resin composites after simulated toothbrushing with whitening dentifrices. The radioactive/relative dentin abrasion (RDA) and radioactive/relative enamel abrasion (REA) of dentifrices were also assessed. Methods: Specimens (n=10) of Tetric N Ceram Bulk Fill (TNCB), Filtek One Bulk Fill (FOB) resin composites, and Z100(Control) were prepared using a cylindrical Teflon matrix. Surface roughness (Ra, µm) was assessed by a roughness meter and the color evaluations (Eab, E00, WID) were performed using a digital spectrophotometer based on the CIELAB system. Three measurements were performed per sample, before and after simulated toothbrushing with 3D Oral-B White Perfection (3DW) and Black is White (BW) dentifrices. The abrasivity (REA and RDA values) of the used dentifrices was also determined by the Hefferren abrasivity test. Results: The Ra values increased significantly in all resin composites after 3DW and BW toothbrushing. The acceptable threshold color varied among resin composites, and TNCB and Z100 presented the highest Eab and 00 for BW dentifrice. The 3DW dentifrice was significantly more abrasive than BW dentifrice on enamel and dentin. Conclusions: simulated toothbrushing with tested whitening dentifrices increased the surface roughness at acceptable levels. The Tetric N Ceram Bulk-fill and Z100 composite showed the highest color alteration in BW. 3D White Perfection dentifrice was more abrasive on dentin and enamel than Black is White. [ABSTRACT FROM AUTHOR]

The most commonly used bleaching agents contain different concentrations of hydrogen peroxide and carbamide peroxide. In the present case, the bleaching procedure was performed using an induced field of cold atmospheric plasma, obtained from dielectric barrier discharge. The therapeutic effect of the device used in the clinical procedure is based on floating electrode dielectric barrier discharge, in which the glass electrode functions as the primary electrode, while the therapeutic area, which in this case is the tooth, represents the secondary electrode. A periodontal (PA) probe is a glass tube filled with a noble gas, which generates an electrical discharge in the gap between the tip of the electrode surface and the therapeutic area, thus producing reactive oxygen species. Bleaching with only the cold atmospheric plasma bleaching technique, without any conventional bleaching agents, was performed successfully for an endodontically treated tooth. The cold atmospheric plasma bleaching technique, which could be a novel approach for the bleaching of non-vital teeth, provides good clinical results and is safe for clinical use. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of propolis as an antioxidant agent on bond strength to enamel after intracoronal bleaching. A total of 160 incisors were endodontically treated. Sixteen teeth were served as control, and the remaining teeth were randomly divided into three main groups according to the bleaching agent used; group 1: Sodium perborate (SP); group 2: Carbamide peroxide (CP); group 3: Hydrogen peroxide (HP). After bleaching, the samples were divided into three subgroups; subgroup A: no antioxidant agent application, subgroup B: sodium ascorbate (SA), subgroup C: propolis (PP). After the antioxidant agents application, the sample's surfaces were washed and dried. After adhesive application, composite resin cylinders were applied to enamel surfaces using tygon tubes and a shear bond strength test was performed. The use of PP significantly decreased the bond strength of composite resin to the enamel (p < 0.05). Using propolis as an antioxidant agent adversely affects the bond strength to enamel after intracoronal bleaching. [ABSTRACT FROM AUTHOR]

Objectives: The objective of the study is to evaluate the bleaching potential of 6% hydrogen peroxide (6% HP) gels containing NF_TiO2 or Nb2O5 irradiated with a violet LED light and the effects on enamel mineral content and surface morphology. Methods: Particles were synthesized, and experimental gels were chemically analyzed by preliminary and accelerated stability tests, pH, and HP decomposition rate. Bovine enamel blocks were treated with 6% HP gels containing (n = 10): 5% NF_TiO2, 5% Nb2O5, 2.5% NF_TiO2 + 2.5% Nb2O5 or without particles (6% HP), irradiated or not with LED, and the control was treated with 35% HP. Color (∆E00) and whitening index (∆WID) variations, surface microhardness (SH), average roughness (∆Ra), Ca-P concentration (EDS), and enamel morphology (SEM) were assessed. Bleaching was performed in 3 sessions of 30 min and 7-day intervals. Data were submitted to two- (pH, decomposition rate, ∆E00, and ∆WID) or three-way ANOVA and Bonferroni (SH), Kruskal–Wallis (∆Ra), and Dunnet tests (α = 0.05). Results: No changes in the gel's color, odor, or translucency were observed. The pH (6 to 6.5) remained stable over time, and light irradiation boosted the HP decomposition rate. NF_TiO2 and Nb2O5-containing gels displayed higher ∆E00 and ΔWID when light-irradiated (p < 0.05). Nb2O5 and Nb2O5 + NF_TiO2 decreased enamel SH (p < 0.05), but no SH changes were found among groups (p > 0.05). No differences among groups were noted in ∆Ra, Ca-P content, and enamel morphology after treatments (p > 0.05). Conclusion: Experimental light-irradiated 6% HP gels containing NF_TiO2 or Nb2O5 were chemically stable and exhibited bleaching potential comparable with 35% HP. Clinical relevance: Low-concentrated HP gels containing NF_TiO2 or Nb2O5 and light-irradiated stand as a possible alternative to in-office bleaching. [ABSTRACT FROM AUTHOR]

Abstract The effectiveness of at-home dental bleaching treatments depends on the time that bleaching products are in contact with the teeth surface and, consequently, on the adequate use of associated custom acetate trays. Objective This randomized single-blinded trial aimed to analyze if the daily usage time of these products influences the patient’s compliance behavior when submitted to monitored at-home dental bleaching. Secondary outcomes were color change and tooth sensitivity. Methodology Sixty-six volunteers were randomly distributed into three groups (n=22): patients were instructed to use the trays for 2 (G2), 4 (G4), and 8 (G8) hours daily. The daily dental bleaching compliance behavior was measured using a microsensor inserted into the trays. Subjective and objective color evaluation assessments were adopted at baseline (T0), one (T1), two (T2), and three weeks (T3) after the beginning of the bleaching treatment, as well as two weeks after the treatment (T4). Tooth sensitivity was analyzed using the VAS scale, ranging from T1 to T4. Results G2 showed a greater degree of cooperation than G8 and cooperation was inversely proportional to the recommended usage time. Significantly higher color change was observed in the upper arch for G8 when compared to G2 in subjective analysis, from T1 to T4. There were no statistical differences between the groups in objective analysis. Conclusion Shorter recommended usage time of the bleaching product may improve the patient's compliance with at-home dental bleaching treatments. However, increased daily usage time may promote better subjective color change. Bleaching sensitivity was more significant in the first week for a longer time of use.

Abstract Despite the availability of in-office bleaching gels with a 6% concentration of hydrogen peroxide (HP), these gels have not been evaluated in younger patients. They are commercially available with a tip, associated or not with a brush, where the tip with a brush spreads the gel over the entire surface to have a smaller thickness (thin layer) since the manufacturers indicate the application of a thin layer of gel. Objective This randomized, split-mouth, double-blind clinical trial evaluated the efficacy of in-office bleaching with 6% HP in adolescents using different application tips, as well tooth sensitivity (TS) and aesthetic self-perception. Methodology Sixty participants were randomized for 6% HP self-mixing bleaching gel tip design: without brush and with brush. In-office bleaching was performed in 3 sessions of 50 minutes. Color change was evaluated using a digital spectrophotometer (ΔE ab , ΔE 00 , and ΔWI D ) and color guide (ΔSGU), the absolute risk and intensity of TS with a visual analogue scale and aesthetic self-perception with the oral aesthetic scale (a=0.05). Results The groups achieved similar bleaching regardless of the application tip (p>0.05). However, only for ΔWI D , a significant mean difference (MD) was observed in the third week (MD 2.3; 95% CI 1.2 to 3.3; p < 0.001) and at one month (MD 1.6; 95% CI 0.6 to 2.6; p < 0.03) favoring the tip without brush. Regarding TS, 45% in the tip-without-brush group and 33% in the tip-with-brush group reported TS (odds ratio 0.61; 95% CI 0.29 to 1.28; p0.36). All patients reported improved aesthetic self-perception after bleaching (MD -1.3; 95% -1.8 to -0.9; p

This systematic review examines studies focusing on tooth bleaching and its effects on healthy enamel or incipient caries and bacterial adhesion. The aim is to explore the impact of different bleaching agents on incipient caries lesions and healthy enamel. Clinical studies, in vitro studies, and observational studies that compared at least two groups were included. A search strategy was used to select studies from the MEDLINE via Pubmed and Scopus databases. Two evaluators performed data extraction, screening, and quality assessment independently. Only studies written in English were included. From 968 initial records, 28 studies were selected for a full-text evaluation. Of these, 7 studies were classified as cluster 1 (bacterial adherence on teeth), 12 studies as cluster 2 (no bacteria involved), 4 studies as cluster 3 (no teeth deployment), and 5 clinical studies were cluster 4. Of the selected studies, 6 (21.4%) supported increased bacterial attachment capacity and cariogenic dynamics, 4 (14.3%) decreased adhesion and cariogenic activity, 7 (25%) showed no difference, and 11 (39.3%) followed a different methodological approach and could not be categorized. The risk of bias appeared to be high, mainly because of the different methodologies in the studies, so we cannot reach a confident conclusion. Nevertheless, as far as carbamide peroxide bleaching is concerned, there does not seem to be a clinically significant alteration, neither in microorganism counts nor in enamel microstructure.

Purpose: The purpose of the study is to evaluate the effect of intracoronal bleaching agents (IBA) on discolored teeth with triple-antibiotic paste (TAP). Methods: Twenty-six extracted maxillary incisors were discolored for 3 weeks with TAP, containing metronidazole, ciprofloxacin, and doxycycline. Following CIE L*a*b* system, colors were measured at baseline and at 1, 2, and 3 weeks. Specimens, bleached intracoronally, were randomly divided into two groups (n = 13): 35% hydrogen peroxide (HP) and 37% carbamide peroxide (CP). Color changes (ΔE) were based on the spectrophotometric measurements at baseline, 3rd, 6th, and 9th days and analyzed using analysis of variance, Bonferroni, and Student t-tests (p < 0.05). Results: The discoloration increased from baseline to week 3 with significant difference (p < 0.05). The highest ΔE value was observed at week 3 (16.54 ± 5.90). In HP, there was no significant difference on the 6th day compared to the 3rd day (p > 0.05), but a significant difference on the 9th day (p < 0.05). In CP, ΔE was not statistically different among evaluated days. On day 9, HP had a significantly higher ΔE than CP (p = 0.032). Conclusion: TAP caused clinically unacceptable ΔE, increasing over time (ΔE ≥ 3.3). IBA was found effective on discolored teeth. 35% Hydrogen Peroxide was more effective than Carbamide Peroxide on the 9th days. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: Sodium hypochlorite is commonly used as a household bleaching agent (for example, the Clorox brand). Sodium hypochlorite poisoning with ingestion of a bleaching agent is often observed in clinical practice. Current Concepts: Ingestion (intentional or accidental) is the most common route of exposure to household bleaching agents. Accidental ingestion of household bleaching agents is rarely clinically important. However, ingestion of a large amount of a dilute formulation or a high-concentration preparation of bleaching agents can result in severe and rarely fatal corrosive injury. Therefore, prompt supportive care is essential because a specific antidote is currently unavailable. Severe poisoning requires hospital admission. Emergency endoscopy and thoracic and abdominal computed tomography are warranted to aid with diagnosis and management of hypochlorite-induced corrosive injury in patients with severe poisoning, who develop clinical features suggestive of corrosive injury. Discussion and Conclusion: Intentional poisoning, which accounts for most cases of household bleaching agent poisonings in Korea, is likely to cause severe corrosive injuries. Therefore, it is necessary to gain deeper and accurate understanding of the clinical aspects and treatment of poisoning by household bleaching agents. [ABSTRACT FROM AUTHOR]

Aim: To determine if the artificial staining with black tea (BT) influences the enamel microhardness before in-office bleaching and if BT staining is necessary to evaluate the efficacy of bleaching with 35% hydrogen peroxide Methods: Enamel/dentin blocks were randomized into groups according to the staining protocol (n=5/group): (CO) control -- maintained in artificial saliva solution (AS); (BT4) immersed in black tea solution for 4 h; (BT24) immersed in black tea solution for 24 h. After the staining protocols, all specimens were kept in AS for one week, followed by bleaching (three sessions of HP application for 40 min). Knoop surface microhardness (kgF/mm²) was determined at baseline (T0), after staining (T1), after 7 days of storage in AS (T2), and after bleaching (T3). The color (ΔE00) and coordinate changes (ΔL, Δa, Δb) were measured using a digital spectrophotometer at T0 and T3. Data were submitted to one-way (ΔE00, ΔL, Δa, Δb) or two-way ANOVA repeated measures (kgF/mm²) and Tukey's test (a=5%). Results: The staining protocols (BT4 and BT24) promoted significantly lower microhardness (T1 and T2, p<0.05) than CO, whereas CO was the only group to maintain microhardness values over time. Bleaching promoted perceptible ΔE00 without a significant difference among the groups regardless of the staining protocol (p=0.122). CO and BT4 showed no differences in terms of ΔL and Δa (p>0.05), but BT4 displayed a higher Δb than CO. Conclusion: The artificial staining with BT negatively affected the enamel surface microhardness and was not essential to evaluate the efficacy of 35% hydrogen peroxide bleaching. [ABSTRACT FROM AUTHOR]

Background: The application of skin-whitening products to have fairer and lighter skin tone has now become common practice worldwide. Research supports that even skin distribution and fairer skin are the symbol of attractiveness and superiority. Objective: This study aims to determine the belief and awareness about the composition and hazardous effects of skin-whitening products among Saudi population. Design: This was a descriptive cross-sectional study. Methods: A total of 395 respondents participated in the study. This was a cross-sectional survey study that was carried out in Riyadh, Saudi Arabia. The two-part questionnaire was filled by a convenience sample of 395 Saudi participants. The survey questions were related to whitening creams effectiveness, reasons of use, and the safety of the whitening products. The survey data were analyzed using SPSS version 21. Results: The most representative age group who responded was 18–25 years (26%), 73% were female (n = 185), and 53.1% were married. Regarding the level of knowledge among respondents on skin-whitening cream-negative implications, it was found that there is an association between age and whitening cream side effects (

Objective: This study evaluated in vitro, the effects of carbamide peroxide 10% (CP) associated with Carbopol® (CP-ct) and Aristoflex® (CP-at) thickeners on human gingival fibroblasts (HGF) cytotoxicity and assessed in situ their effects on dental enamel. Material and methods: The cytotoxicity was analyzed using MTT - Vybrant® proliferation test. For in situ stage, 144 bovine enamel/dentin blocks were randomized into seven groups (n=12). Samples were stained, fixed in intraoral palatal devices and bleached for 4 h, during 14 days, with: Carbopol thickener (ct), Aristoflex thickener (at), CP-ct, CP-at, CP without thickener (CP-wot), Commercial CP (CP-com). The samples had their microhardness (SMH), roughness (Ra) and color analyzed using a microdurometer, a rugosimeter and a spectrophotometer, respectively. The analyses were performed at baseline and 24-h after completion of tooth bleaching. Results: Different thickeners were similar regarding their cytotoxicity. The experimental gels with Carbopol exhibited lower SMH values, while the groups treated with CP exhibited higher Ra values. For the color change results, the groups treated with CP had values above the acceptability and perceptibility limits. Conclusion: CP-at was able to promote an effective bleaching with less alterations of the tooth surface compared to the CP-ct. Hence, Aristoflex stands as a promising thickener in conjunction with CP in order to preserve the physical properties of dental enamel after home bleaching.

Aim: This study aimed to evaluate the effect of using whitening dentifrices during at-home bleaching on the shear bond strength (SBS) of resin composite to dentin, and investigate whether the increased polymerization time would improve SBS. Methods: Ninety-six bovine incisors were divided into 4 groups of 24, according to the whitening treatment applied as follows: group 1, at-home bleaching + brushing with a regular dentifrice; group 2, at-home bleaching + brushing with a whitening dentifrice containing ozone; group 3, at-home bleaching + brushing with a commercial whitening dentifrice; and group 4 (control), no whitening/brushing treatment. Each group was divided into two subgroups (n = 12) to assess the effect of curing time (20 versus 80 s) on SBS. A self-etch adhesive was bonded to dentin, and after 2-day water storage, SBS was determined. Results: SBS was significantly affected by the whitening treatment (P = 0.03), but increasing the curing time had no significant effect on SBS (P = 0.137). Bond strength in group 1 was comparable to the control group (P > 0.05). The specimens in group 3 displayed significantly lower SBS than either group 4 or group 1 (P > 0.05). No significant difference was observed between the SBS of group 2 compared to any other group (P > 0.05). There was no significant association between the treatment group and failure type (P > 0.05). Conclusion: The bonding interface was not negatively influenced by the at-home bleaching procedure. However, using a commercial whitening dentifrice during at-home bleaching produced a significant detrimental effect on SBS. Extending the curing time would have no beneficial effect on adhesion to a whitened dental substrate. [ABSTRACT FROM AUTHOR]

Objectives : To investigate the physical–chemical properties of home bleaching gels based on Carbamide Peroxide (CP) and Hydrogen Peroxide (HP) after accelerated stability (AS) and its effects on enamel. Materials and Methods: A total of 360 bovine teeth blocks were divided (n = 12): Control, CP10%-Whiteness Perfect, CP10%-Pola Night, HP7.5%-Pola Day, and HP7.5%-White Class Calcium. Microhardness (KHN), roughness (Ra), color (ΔE and ΔE00), hardness, compressibility, elasticity, cohesiveness, adhesiveness, weight, pH, and calcium (Ca) quantification in enamel were analyzed without storage of the bleaching gels and after AS at 1 and 3 months. Data of Ca, KHN, and Ra were analyzed through mixed models for repeated measurements and the Tukey–Kramer test. Values of weight, hardness, compressibility, and elasticity were analyzed with two-way ANOVA and Tukey's test. ΔE/ΔE00 data, cohesiveness, and adhesiveness were analyzed with Kruskal–Wallis and Dunn tests (α = 0.05). Results: Groups subject to AS had lower ΔE and ΔE00 compared to those without storage. Lower KHN and higher Ra values were found after bleaching treatment in all groups compared to controls. Higher amounts of Ca were found on the first day of evaluation in the gels subject to AS for 3 months, regardless of the bleaching agent used. Conclusions: Incorrectly stored bleaching gel accentuates adverse effects on enamel. Temperature and humidity interfere directly with the chemical stability of bleaching agents, reducing their properties. Clinical relevance: HP is an unstable oxidizing agent when stored at high temperatures. Therefore, pH becomes more acidic and potentiates the demineralizing effect on enamel. [ABSTRACT FROM AUTHOR]

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

Copyright of Acta Stomatologica Croatica is the property of Acta Stomatologica Croatica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This work proposes an evaluation of the Crystalline Index (CrI) in function of the bleaching process employed during cellulose extraction from corn husk, for further characterization using CP/MAS 13C NMR, XRD, and FT-IR. In that sense, CrI values were calculated by FT-IR and the bands associated with the crystalline and amorphous regions were observed at 1424 cm−1 and 896 cm−1, respectively. Similarly, the signals due to ordered (89.1 ppm) and disordered (84.2 ppm) cellulose chains were detected by solid-state 13C NMR, while the Segal equation was only used for comparison purposes. Additionally, PCA studies showed consistent results attributed to the crystalline region in cellulose domains analyzed by both, FT-IR and solid-state 13C NMR. The results revealed the coexistence of cellulose I/cellulose II and its effect on CrI, as well as the incomplete mercerization process, in some cases non-cellulosic residues can cause an overestimation of CrI. Additionally, the thermal stability and the glass transition temperature were determined by TGA/DTA and DSC analyses. Finally, a partially fibrillated-network morphology with a diameter of 20.47 ± 2.77 μm was observed in cellulose bleached with peracetic acid, whereas organosolv method provides flexible and clean microfibrils with diameter sizes between 10 and 9 μm. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: In this study, the bleaching effect and surface damage of two types of over-the-counter home tooth bleaching agents were explored using an in vitro study of bleaching agents applied to bovine teeth specimens for 14 days.Methods: Domestic over-the-counter home tooth bleaching agents of gel and patch form that shared common active ingredients and manufacturers were selected and tested. The experiment specimens were made using composite resin with bovine tooth samples and then measured the initial microhardness. Specimens were then divided into a Gel group and a Patch group and underwent bleaching treatment once a day for two weeks for 30 to 60 minutes (recommended) or 7 hours. All specimens were coffee-stained prior to bleaching. The bleaching effect was measured using a spectrophotometer and surface damage was measured using a microhardness meter.Results: The difference in color following the bleaching procedure was positive in both the Gel and Patch group, although there were no statistically significant differences in bleaching effect between groups. There was no significant difference in bleaching effect based on duration. The microhardness test revealed that both the Gel group and the Patch group had surface damage after bleaching. The greatest surface damage was found in the Patch group that had undergone a 7-hour bleaching treatment, although the differences were not statistically significant.Conclusion: The bleaching effect of the home tooth bleaching agent was visible to the naked eye. However, longer applications than recommended did not result in greater bleaching, unlike consumers’ expectations, and instead increased the chance of enamel damage. As such, there is a need for consumers to be alert and adhere to recommendations provided by each company.

ABSTRACT Molar incisor hypomineralization is an increasingly common condition in our population. This condition can have great impact on the esthetics, function, and well-being of the child. This paper reports a case of a young patient diagnosed with this condition affecting all the first permanent molars and lower incisors, particularly teeth 31 and 41. The molars were treated with direct resin restorations with cusp coating and the incisors aesthetic was restored with different techniques such as bleaching with sodium hypochlorite, micro-abrasion and resin restorations. This treatment plan aimed to restore the proper teeth function, treat the already existing hypersensitivity and algic complains and to improve the aesthetic of the anterior sector. The presented case shows a conservative approach to deal with the molar incisor hypomineralization condition with satisfactory results after 1-year follow-up.

Purpose: To compare the effect of toothbrushing abrasion with hydrated silica-based whitening and regular toothpastes on root dentin using contact profilometry.Materials and Methods: Ninety dentin specimens (4 x 4 x 2 mm) were randomly divided into five experimental groups (n = 18) according to the toothpaste: three whitening (W1, W2 and W3) and two regular toothpastes (R1 and R2) produced by two different manufacturers. Using a brushing machine, each specimen was brushed with a constant load of 300 g for 2500 cycles (4.5 cycles/s). The toothpastes were diluted at a ratio of 1:3 w/w (dentifrice:distilled water). The brush diamond tip of the profilometer moved at a constant speed of 0.05 mm/s with a force of 0.7 mN.Results: The average value of brushing abrasion in μm (mean ± SD) was obtained from five consecutive measurements of each specimen: W1 = 8.86 ± 1.58, W2 = 7.59 ± 1.04, W3 = 8.27 ± 2.39, R1 = 2.89 ± 1.05 and R2= 2.94 ± 1.29. There was a significant difference between groups (ANOVA, p<0.0001). Post-hoc Tukey's test for multiple comparisons showed differences between all the whitening and regular toothpastes, but not among the whitening nor among the regular toothpastes.Conclusion: The whitening toothpastes tested can cause more dentin abrasion than the regular ones. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this trial was to evaluate bleaching effectiveness, tooth sensitivity and gingival irritation of whitening patients with 10% versus 37% carbamide peroxide (CP). Methods: Eighty patients were selected by inclusion and exclusion criteria and randomly allocated into two groups (n = 40): 37% CP and 10% CP. In both groups, patients performed whitening for 3 weeks, 4 h/day for 10% group and 30 min/day for 37% group. Color was evaluated with Vita Classical, Vita Bleachedguide 3D Master and Spectrophotometer Easyshade, at baseline, weekly and 30 days after treatment. Absolute risk and intensity of tooth sensitivity (TS) and gingival irritation (GI) were assessed with numeric rating scale (NRS) and a visual analog scale (VAS). Color changes were compared with t‐test for independent samples. TS and GI were evaluated with Fisher's exact tests. Mann–Whitney test was used for NRS, and t‐tests for VAS (α = 0.05). Results: The 37% CP group showed faster whitening than 10% group at 1–3 weeks. However, 1 month after conclusion, both groups showed equivalent bleaching (p = 0.06). Regarding sensitivity and gingival irritation, 10% and 37% groups met no significant differences (p > 0.05). Conclusion: The use of 37% CP 30 min/day showed equivalent results to 10% 4 h/day. Clinical significance: The use of 37% carbamide peroxide 30 min/day may decrease the time of tray use in at‐home protocol for whitening because it presents equivalent results to 10% carbamide peroxide 4 h/day. [ABSTRACT FROM AUTHOR]

Objective: This study evaluated the influence of over‐the‐counter agents on the maintenance of color and microhardness of the enamel after home bleaching protocol. Materials and methods: Specimens of bovine teeth (6 × 6 × 2 mm) were prepared, and color (Easyshade, VITA) and microhardness (HMV‐2, Shimadzu) readings were performed. All the specimens were bleached using 22% carbamide peroxide (22%CP), except for the control group, and then separated into seven groups (n = 10) according to the interaction of toothpaste (whitening, conventional, and whitening with peroxide) and mouth rinse (whitening and conventional). The study simulated 1 year of toothbrushing (Pepsodent, MAVTEC) and mouth rinse by immersion. After that, final color and microhardness measurements were performed. Data were analyzed by one‐way ANOVA, Tukey's test (P <.05). Results: The group submitted to 22%CP + whitening toothpaste + whitening mouth rinse showed higher color maintenance (P <.05) than the control group. The perception of whitening of teeth (ΔWID) was higher than the color change (ΔE00). There was a decrease in microhardness after treatment with 22%CP + conventional toothpaste + whitening mouth rinse. Conclusions: Over‐the‐counter products can help with the maintenance of tooth whitening after bleaching with carbamide peroxide; however, special attention should be given since the association of products can also reduce the microhardness of the dental enamel. Clinical significance: The association between whitening toothpastes and mouth rinses might be beneficial for maintaining color during 1 year after bleaching treatment. [ABSTRACT FROM AUTHOR]

Copyright of RGO: Revista Gaúcha de Odontologia is the property of RGO: Revista Gaucha de Odontologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aim: To evaluate the influence of the parameters L* a* b* on the variation of the color of bovine tooth enamel submitted to artificial darkening, after simulated brushing, with whitening toothpastes containing blue covarine. Methods: To undertake this study in vitro, 60 specimens (SP) were divided into 6 groups (n=10): control group (CGwater) and 5 test groups (GT1-Colgate Total 12, GT2-Oral-B 3D White Perfection, GT3-Colgate Luminous Instant White, GT4-CloseUp White Diamond Attraction, GT5-Sorriso Xtreme White). The specimens were darkened with coffee and submitted to simulated brushing for 6, 12, and 24 months. The alteration in the color was evaluated using CIELAB parameters and the ΔL, Δa, Δb and ΔE were calculated. The data was analyzed through generalized linear models using the R program and considering a level of significance of 5%. Results: The parameters L*, a* and the ΔL, Δa obtained better results in the test group than in the control group. There were no statistical differences between CG and the test groups for the evaluation of the b* parameter. In the evaluation of the Δb, the GT3 differed statistically from the CG. In relation to the ΔE, all the group tests showed a variation in color statistically greater than that of the CG and the GT4 showed the greatest variation, not differing from the GT3 during the periods studied. Conclusion: The mechanical and optical whitening agents positively influenced the values L*a* and b*, as well as in its variations and in the ΔE. It is important to emphasize, however, that to analyze tooth whitening it is necessary to evaluate their parameters together. [ABSTRACT FROM AUTHOR]

Background: The application of skin-whitening products to have fairer and lighter skin tone has now become common practice worldwide. Research supports that even skin distribution and fairer skin are the symbol of attractiveness and superiority. Objective: This study aims to determine the belief and awareness about the composition and hazardous effects of skin-whitening products among Saudi population. Design: This was a descriptive cross-sectional study. Methods: A total of 395 respondents participated in the study. This was a cross-sectional survey study that was carried out in Riyadh, Saudi Arabia. The two-part questionnaire was filled by a convenience sample of 395 Saudi participants. The survey questions were related to whitening creams effectiveness, reasons of use, and the safety of the whitening products. The survey data were analyzed using SPSS version 21. Results: The most representative age group who responded was 18-25 years (26%), 73% were female (n = 185), and 53.1% were married. Regarding the level of knowledge among respondents on skin-whitening cream-negative implications, it was found that there is an association between age and whitening cream side effects (<0.05). Ages between 18 and 25 (73.5% said yes) and between 31 and 35 (75.6%) suffer higher from side effects of whitening creams as compared to the other age groups. Conclusion: The analysis shows that cosmetic use of skin-whitening creams is more common among females. The people of all age groups were not aware of the deleterious effects of skin-whitening creams. From the study, it was found that people who suffer from the negative effects of creams were mostly of age less than 35. [ABSTRACT FROM AUTHOR]

Objective: To compare at‐home systems with reduced daily time of use (10% hydrogen peroxide [HP] gel with prefilled (PT) or customized trays (CT), and 10% carbamide peroxide [CP] gel), with the conventional nightguard vital bleaching (10% CP). Bleaching efficacy, adverse effects, and patient's satisfaction were evaluated. Methods: Sixty participants were randomly divided into treatments (14 days): Opalescence GO (OGO)‐10%HP PT‐30 min, White Class‐10%HP CT‐30 min, Opalescence PF‐10%CP CT‐2 h, and Opalescence PF‐10%CP CT‐8 h. Color difference (visual and spectrophotometer), tooth sensitivity (visual analogue scale), gingival condition (Löe index), enamel mineralization (laser fluorescence), and patients' satisfaction (questionnaire) were assessed. Statistical tests were applied (5%). Results: After 1 year, color difference was similar for the groups (p > 0.05). All groups showed similar sensitivity risk (p > 0.05). The intensity of sensitivity and gingival irritation was mild for all gels, but higher for OGO. Fluorescence after bleaching remained similar to those of sound enamel. All participants were satisfied with treatments. Conclusions: All systems produced similar bleaching efficacy, which was maintained after 1 year. Patients were satisfied with bleaching outcomes. Tooth sensitivity occurred in all groups, but with overall mild intensity. No relevant gingival irritation and enamel demineralization was observed. Clinical significance: Bleaching with 10% HP gels in prefilled and CTs represent efficacious alternative for tooth color change, with patients' acceptance similar to conventional 10% CP. Patients must be warned about the mild sensitivity and gingival irritation potential, mainly with PTs. [ABSTRACT FROM AUTHOR]

Introduction: The use of light sources during the application of bleaching can reduce the time and improve the results, but at the same time this can increase the dental temperature. The objective of this study was to evaluate the performance of two bleaching agents and the increase in dental temperature with the use of light emitted by diodes (LED)‐unit. Materials and methods: Forty third molars were obtained and randomized: the whiteness without lamp (WHN) and Pola office without lamp (PON) groups, two bleaching systems based on 35% hydrogen peroxide were used, according to manufacturer specifications. For the whiteness with lamp (WHL) and Pola office with lamp (POL) groups the same bleaching agents were light boosted. A spectrophotometer and ∆WID equation was used to record and analyzed teeth color. An infrared thermometer was used to record the external and internal temperature. A ∆T was obtained by the difference of the temperature of the groups with and without LED (WHN‐WHL and PON‐POL). For statistical analysis Kruskal‐Wallis test and Anova test were performed. Results: The WHN, PON, WHL, and POL groups reported ∆WID values of 4.88 ± 1.08, 9.26 ± 3.27, 5.70 ± 2.48, 12.08 ± 5.44, respectively. The dates of internal temperature were 1.01 and 1.07°C, and for external temperature were 1.61 and 1.15°C respectively. Conclusions: With the limitations of this study, both bleaching agents reported a significant increase in ∆WID with and without association of light. Significant temperature increases were also observed. The highest average temperature increase was approximately 1.61°C. Clinical significance: Bleaching agents boosted with LED may improve the results of bleaching, but it is not essential to obtain good results. [ABSTRACT FROM AUTHOR]

Discoloration of teeth in the anterior region can cause considerable cosmetic impairment. One of the techniques which is commonly used for bleaching of endodontically treated teeth is “walking” bleach techniques, and it provides satisfactory results. Based on the clinical reports with nonvital tooth bleaching, it is a viable, esthetic treatment for the discolored tooth. Its conservative nature makes it an important part of an esthetic dentistry treatment. This case report presents two cases, in which nonvital bleaching was done by walking bleach technique. Regular follow-up after a period of 4 weeks showed a significant reduction in the discoloration of teeth.

Gláucia Cristina Rodrigues Nascimento,1 Mara Eliane Soares Ribeiro,1 Marcella Yasmin Reis Guerreiro,1 Eduardo Luís de Souza Cruz,2 João de Jesus Viana Pinheiro,2 Sandro Cordeiro Loretto11Dental Materials Laboratory of the Postgraduate Program in Dentistry, Institute of Health Sciences, School of Dental, Federal University of Pará, Belém, Pará, Brazil; 2Department of Oral Pathology, School of Dental, Federal University of Pará, Belém, Pará, BrazilCorrespondence: Sandro Cordeiro LorettoDental Materials Laboratory of the Postgraduate Program in Dentistry, Institute of Health Sciences, School of Dental, Federal University of Pará, Avenue Conselheiro Furtado, Number 2312, Tower Oásis, Ap. 401, Cremação, Belém, Pará 66.040-100, BrazilTel +55 9 198 122 3477Email sandroloretto@hotmail.comAim: This study evaluated the effect of sodium ascorbate (SA) on the proteolytic activity of matrix metalloproteinases (MMPs) and investigated the related effects on the bond strength of bleached dentin.Materials and methods: Eighty freshly extracted human third molars were randomly divided according to treatment (bleaching or SA application), type of analysis (microshear or measuring MMP activity), and post-bleaching time to assess bond strength (24 hrs or 30 days). Data from both analyses were subjected to one-way analysis of variance to detect differences among groups, followed by Tukey’s multiple comparison test (p≤0.05).Results: Dental bleaching significantly reduced bond strength values when the adhesive strategy was performed after 24 hrs (despite the SA treatment) or 30 days after the bleaching procedure. However, after 30 days, the bond strength values of the groups who received bleaching or SA application were similar to those of the unbleached group. Dental bleaching caused the activation of MMPs, and SA did not influence this activity.Conclusion: It was concluded that SA does not affect the activity of MMPs or the bond strength in bleached dentin immediately after the bleaching treatment.Keywords: tooth bleaching, antioxidants, bleaching agents, dental bonding

Aims: Residual peroxide on the enamel surface and in the interprismatic spaces decreases the shear bond strength (SBS) of composite to bleached enamel. Evidence shows that 10% sodium ascorbate can efficiently neutralize the singlet oxygen generated by the bleaching agents. This study aimed to assess the effect of duration of application of sodium ascorbate on SBS of composite to bleached enamel. Materials and Methods: This in vitro experimental study was conducted on 30 sound human third molars, which were randomly divided into three groups (n=10). In group 1, the teeth were bleached for 45 minutes and were then subjected to immediate bonding and restoration with composite resin. In groups 2 and 3, the teeth were bleached, immersed in 10% sodium ascorbate solution for 5 (group 2) and 10 (group 3) minutes and were then bonded and restored with composite, and the SBS was then measured. Results: The highest SBS (14.02±8.6MPa) was noted in group 3 (immersion in 10% sodium ascorbate for 10 minutes before bonding). The lowest SBS was noted in group 1 (immediate bonding after bleaching) (p

Aim: To evaluate the influence of the parameters L* a* b* on the variation of the color of bovine tooth enamel submitted to artificial darkening, after simulated brushing, with whitening toothpastes containing blue covarine. Methods: To undertake this study in vitro, 60 specimens (SP) were divided into 6 groups (n=10): control group (CGwater) and 5 test groups (GT1-Colgate Total 12, GT2-Oral-B 3D White Perfection, GT3- Colgate Luminous Instant White, GT4-CloseUp White Diamond Attraction, GT5-Sorriso Xtreme White). The specimens were darkened with coffee and submitted to simulated brushing for 6, 12, and 24 months. The alteration in the color was evaluated using CIELAB parameters and the ΔL, Δa, Δb and ΔE were calculated. The data was analyzed through generalized linear models using the R program and considering a level of significance of 5%. Results: The parameters L*, a* and the ΔL, Δa obtained better results in the test group than in the control group. There were no statistical differences between CG and the test groups for the evaluation of the b* parameter. In the evaluation of the Δb, the GT3 differed statistically from the CG. In relation to the ΔE, all the group tests showed a variation in color statistically greater than that of the CG and the GT4 showed the greatest variation, not differing from the GT3 during the periods studied. Conclusion: The mechanical and optical whitening agents positively influenced the values L*a* and b*, as well as in its variations and in the ΔE. It is important to emphasize, however, that to analyze tooth whitening it is necessary to evaluate their parameters together.

Background: To evaluate the changes in the micro-hardness and surface roughness of enamel treated with three different concentrations of in-office bleaching agents. Materials and Methods: In this in vitro study, 60 human incisors were divided into two groups (Group A and Group B). To obtain the baseline values, a Vickers tester was used to determine the surface microhardness in Group A, and a Surtronic tester was used for evaluation of surface roughness in Group B. Each group was then further subdivided into three subgroups and subjected to bleaching with Dash (Groups A1 and B1), Pola Office (Groups A2 and B2), and Opalescence Boost (Groups A3 and B3) containing 30%, 35%, and 40% hydrogen peroxide (HP), respectively. Samples were again subjected to testing to obtain the postbleaching values. Pre- and postbleaching data were analyzed by paired t-test. Intergroup comparison was carried out using one-way ANOVA (P < 0.05). Results: A significant decrease in microhardness values was observed following bleaching in all the three groups, with Group Al showing maximum percentage decrease (2.58%), followed by Group A2 (1.23%) and Group A3 (0.73%). Furthermore, an increase in surface roughness was observed following bleaching, with Group Bl showing maximum percentage increase (14.80%), followed by Group B2 (8.25%) and Group B3 (5.79%). However, there was no significant difference in either microhardness or surface roughness when comparing the postbleaching values among the three bleaching agents. Conclusion: In-office bleaching agents may adversely affect the microhardness and roughness of enamel surface which are not related to the concentration of HP used. [ABSTRACT FROM AUTHOR]