Influence of residues from bioceramic sealer on the bond interface with universal adhesive in different application modes.

This study evaluated the effect on adhesive layer thickness, bond strength, and adhesive failure pattern of the application of universal adhesive (Scotchbond Universal) using either manual or rotary brush in dentin previously impregnated with bioceramic sealer (Sealer Plus BC) using a manual brush, at 24 h and 1 year. Eighty-eight bovine crowns were divided into four groups (n = 22) according to the intervention: (i) use of bioceramic sealer and adhesive application using manual brush, (ii) use of bioceramic sealer and adhesive application using rotary brush, (iii) use of resin sealer and adhesive application using manual brush, and (iv) use of resin sealer and adhesive application using rotary brush. Subsequently, specimens were restored with a composite resin (Filtek Z-250). Adhesive layer thickness was evaluated using confocal microscopy. Bond strength was assessed using the microtensile bond strength test, and adhesive failure pattern was evaluated under a stereomicroscope. Data were analyzed using two-way ANOVA/Tukey tests. Specimens where a rotary brush had been used exhibited lower adhesive layer thickness. Specimens treated with resin sealer and using a manual brush showed lower bond strength values and a higher occurrence of adhesive failures at 24 h and 1 year than specimens treated with bioceramic sealer and using rotary brush for adhesive application.

Evaluation of different mechanical cleaning protocols associated with 2.5% sodium hypochlorite in the removal of residues from the post space.

Aims: This study evaluated the effectiveness of different mechanical protocols using rotary brush (RB), ultrasonic tip, and oscillatory system (OS) associated with 2.5% sodium hypochlorite (NaOCl) in the removal of residues and dentin permeability in the cervical and apical segments of the post space. Settings and Design: Experimental in vitro study. Methods: Forty roots from human first molars were prepared and divided into four groups according to the cleaning protocols: Control (CO), NaOCl 2.5% conventional irrigation with a syringe; RB associated with NaOCl 2.5%; ultrasonic tip (US) associated with NaOCl 2.5%; OS associated with NaOCl 2.5%. Statistical Analysis Used: The persistence of residues was evaluated by scanning electron microscopy and data submitted to Kruskal-Wallis and Dunn tests, and dentin permeability evaluated by confocal microscopy and date submitted to ANOVA one-way and Tukey's tests (P = 0.05). Results: There were no differences in residue cleaning among the CO, RB, US, and OS groups, regardless of the analyzed root segment (P > 0.05). When comparing groups, dentin permeability in the CO group was significantly lower in the cervical segment (P < 0.05). Conclusions: The OS group promoted the highest permeability value in the apical segment. RB, US, and OS are similar in removing residues from the post space. However, OS results in higher dentin permeability in the apical segment.

Influence of blue and violet LED and infrared laser on the temperature of bleaching protocols in different concentrations of hydrogen peroxide.

BACKGROUND: The photo-acceleration of bleaching gels by lights has been extensively researched. However, the induced temperature increase during this process needs to be further evaluated to prevent damage to the dental pulp. Therefore, the objective of this study was to evaluate the surface and intrapulpal temperature kinetics of different concentrations of hydrogen peroxide (HP) gels photo-accelerated by blue or violet light and infrared laser. METHODS: The whitening gels at concentrations of HP35, HP15, and HP6 % were irradiated with blue and violet LED/laser on the surface of a human canine tooth. The surface temperature variation (∆Ts) was evaluated using a pH meter, while the intrapulpal temperature variation (∆Ti) was assessed using a digital thermometer at intervals of 1, 15, and 30 min. Statistical analysis was conducted using a Two-way repeated measures ANOVA test, and Bonferroni post-test was applied at a significance level of 5 %. RESULTS: All violet LED photo-accelerated groups showed a higher increase in ∆Ts compared to the blue LED/laser groups. However, there were no significant differences between the groups for ∆Ti. CONCLUSION: Although the photo-acceleration of HP35 and HP15 % gels with violet LED/laser has a greater increase in surface temperature compared to HP6 % gel, the different light systems do not significantly increase the intrapulpal temperature.

Formulations of NaOCl-based in liquid, gel form or with surfactants on dentin deproteinization before fiber post cementation.

The objective of the study was to evaluate the effects of dentin deproteinization protocols for post space using different formulations containing sodium hypochlorite before fiber post cementation with self-adhesive resinous cement. The groups were divided according to the irrigation protocol (DWC, SHS, SHT and SHG). The residue cleanliness, bond strength, adhesive failure pattern, and tag formation at the adhesive interface between the self-adhesive cement and the dentin were evaluated. For this, analysis in scanning electron microscope, push-out test and confocal laser scanning microscopy were performed. The SHT protocol showed the highest residue cleanliness on the dentin surface of the post space (p<0.05). In addition, SHT protocol showed highest bond strength and tag formation in the cervical and middle thirds (p<0.05). Dentin deproteinization with sodium hypochlorite with surfactant provided the best dentin cleaning of residues, bond strength and tag formation after cementation of the fiber post with self-adhesive cement.

Influence of using different translucent composite resins for customizing fiber post on the bond strength of self-adhesive cement to root dentin.

This study evaluated the influence of different translucent resins (Z350 and Opallis) for customizing fiber posts and light-curing the cementation system using different LED equipment (V, Valo or R, Radii-Cal) on the bond strength and adhesive failure pattern at 24 h and 6 months. Eighty roots were prepared and divided into 4 groups (n=20): ZV (Z350 resin and LED Valo), ZR (Z350 resin and LED Radii-Cal), OV (Opallis resin and LED Valo), OR (Opallis resin and LED Radii-Cal). After post space preparation, the fiber post was customized and cemented with self-adhesive cement and light-curing using V or R LED equipment. Bond strength values were submitted to 2-way ANOVA test. ZV and ZR showed higher bond strength values than the other groups at 6 months of evaluation (p<0.05). The Z350 resin has a favorable influence on the bond strength of self-adhesive cement to root dentin, regardless of the LED polymerization equipment used.

Anti-erosion effect of an experimental varnish on eroded dentin.

This in vitro study evaluated the effect of an experimental varnish containing 20% nano-hydroxyapatite (nHAP) associated with 5% stannous chloride (SnCl2) against erosive-abrasive wear on bovine dentin. Samples of bovine cervical dentin were pre-eroded (0.3% citric acid, pH 2.6 for 10 minutes) and randomized into 4 groups (n=10): Control group - experimental varnish without active ingredient (CG); experimental varnish containing 20% nHAP (nHG); experimental varnish containing 5% SnCl2 (24.800 ppm Sn2+) (SnG); experimental varnish containing 20% nHAP associated with 5% SnCl2 (18.300 ppm Sn2+) (nHSnG). After applying the materials, the erosive-abrasive challenges were performed for five days. Erosive dentin loss and analysis of the pattern of dentinal obliteration were performed by 3D confocal laser microscopy. A one-way ANOVA/Bonferroni test was performed to analyze the data (α=0.05). The SnG and nHSnG experimental groups presented more effectiveness in preventing erosive wear when compared to the other groups (p<0.05). There was no statistically significant difference between the SnG and nHSnG groups (p = 0.731) in tooth structure dentin loss. Regarding the amount of open dentinal tubules, the highest amount of obstructed dentinal tubules was demonstrated in SnG and nHSnG (p < 0.05) when compared to the others. Between SnG and nHSnG there was no significant difference (p = 0.952) in the amount of closed dentinal tubules in the dentin. Experimental varnishes containing 5% SnCl2 associated or not with 20% nHAP showed to be a promising strategy in preventing erosive-abrasive wear of dentin. In addition, nHSnG was able to obliterate dentinal tubules.

Anti-erosion effect of an experimental varnish on eroded dentin

Abstract This in vitro study evaluated the effect of an experimental varnish containing 20% nano-hydroxyapatite (nHAP) associated with 5% stannous chloride (SnCl2) against erosive-abrasive wear on bovine dentin. Samples of bovine cervical dentin were pre-eroded (0.3% citric acid, pH 2.6 for 10 minutes) and randomized into 4 groups (n=10): Control group - experimental varnish without active ingredient (CG); experimental varnish containing 20% nHAP (nHG); experimental varnish containing 5% SnCl2 (24.800 ppm Sn2+) (SnG); experimental varnish containing 20% nHAP associated with 5% SnCl2 (18.300 ppm Sn2+) (nHSnG). After applying the materials, the erosive-abrasive challenges were performed for five days. Erosive dentin loss and analysis of the pattern of dentinal obliteration were performed by 3D confocal laser microscopy. A one-way ANOVA/Bonferroni test was performed to analyze the data (α=0.05). The SnG and nHSnG experimental groups presented more effectiveness in preventing erosive wear when compared to the other groups (p<0.05). There was no statistically significant difference between the SnG and nHSnG groups (p = 0.731) in tooth structure dentin loss. Regarding the amount of open dentinal tubules, the highest amount of obstructed dentinal tubules was demonstrated in SnG and nHSnG (p < 0.05) when compared to the others. Between SnG and nHSnG there was no significant difference (p = 0.952) in the amount of closed dentinal tubules in the dentin. Experimental varnishes containing 5% SnCl2 associated or not with 20% nHAP showed to be a promising strategy in preventing erosive-abrasive wear of dentin. In addition, nHSnG was able to obliterate dentinal tubules.

Resumo Este estudo in vitro avaliou o efeito de um verniz experimental contendo 20% de nano-hidroxiapatita (nHAP) associado a 5% de cloreto estanoso (SnCl2) contra o desgaste erosivo-abrasivo da dentina bovina. As amostras de dentina cervical bovina foram pré-erodificadas (0,3% de ácido cítrico, pH 2,6 durante 10 minutos) e aleatorizadas em 4 grupos (n=10): Grupo controle - verniz experimental sem ingrediente ativo (GC); verniz experimental contendo 20% nHAP (GnH); verniz experimental contendo 5% SnCl2 (24.800 ppm Sn2+) (GSn); verniz experimental contendo 20% nHAP associado a 5% SnCl2 (18.300 ppm Sn2+) (GnHSn). Após a aplicação dos materiais, os desafios erosivo-abrasivos foram realizados durante cinco dias. Perda de dentina erosiva e análise do padrão de obliteração dentinária foram realizadas por microscopia laser confocal 3D. Foi realizado o teste ANOVA/Bonferroni unidireccional para analisar os dados (α=0,05). Os grupos experimentais GSn e GnHSn apresentaram maior eficácia na prevenção do desgaste erosivo quando comparados com os outros grupos (p<0,05). Não houve diferença estatisticamente significativa entre os grupos GSn e GnHSn (p = 0,731) na perda de dentina da estrutura dentária. Relativamente à quantidade de túbulos dentinários abertos, a maior quantidade de túbulos dentinários obstruídos foi demonstrada em GSn e GnHSn (p < 0,05) quando comparada com os outros grupos. Entre GSn e GnHSn, não houve diferença significativa (p = 0,952) na quantidade de túbulos dentinários fechados na dentina. Os vernizes experimentais contendo 5% de SnCl2 associados ou não a 20% de nHAP mostraram ser uma estratégia promissora na prevenção do desgaste erosivo-abrasivo da dentina. Além disso, o GnHSn conseguiu obliterar os túbulos dentinários.

Etch-and-rinse versus self-etch strategy of a universal adhesive in different application methods at the bonding interface of fiber post cementation.

OBJECTIVE: To evaluate the effect of etch-and-rinse (ER) versus self-etch (SE) strategies of a universal adhesive applied with a manual brush (MB) or rotary brush (RB) on the bonding interface of fiber post cementation. METHODS: Forty bovine incisor roots were prepared and divided into four groups according to the methods of application and strategy of universal adhesive use (MB-ER, RB-ER, MB-SE and RB-SE). After 6 months, specimens from different thirds of the post space were evaluated of push-out strength, analysis of adhesive failure patterns, and extent of tags. RESULTS: The RB-ER and RB-SE groups showed the highest bond strength values in the cervical and middle thirds of the post space. Cohesive adhesive failure had the highest incidence in the different thirds of the post space in the ER strategy, regardless of the adhesive application method. The RB-ER group showed the highest tag extensions. CONCLUSIONS: The protocols of universal adhesive application with RB provided the greater bond strength, but only the ER strategy favored the formation of a greater extension of tags at the adhesive interface. CLINICAL SIGNIFICANCE: The application of universal adhesive with RB into the post space increases the strength of the post-cemented fiber bond.

The effect of photobiomodulation using low-level laser therapy on tooth sensitivity after dental bleaching: a systematic review.

The authors aimed to conduct a systematic review to assess data from the current literature on the effectiveness of low-level laser therapy (LLLT) in preventing tooth sensitivity (TS) after tooth whitening (DB). PRISMA guidelines for systematic reviews were followed. Clinical trials evaluating the treatment of LLLT in patients with sensitivity after tooth whitening were selected. A full bibliographic search was performed on May 4, 2021, in the following databases: Embase, MEDLINE via PubMed, SciELO, VHL Regional Portal, Web of Science, Gray Literature, Scopus, ClinicalTrials.gov and Cochrane Library. This study followed Cochrane's recommendations for analyzing risk of bias. A total of 1054 studies were found (255 studies were excluded because they were duplicates and 785 because of titles and abstracts). Only 14 articles were selected for analysis, of which eight were excluded because they had one or more exclusion criteria, resulting in six articles included in this systematic review, the vast majority being classified as low risk of bias. The studies reviewed indicated that LLLT showed promise in preventing TS after TB. However, evidence is limited and more clinical trials with low risk of bias are needed to reach a definitive conclusion on the action of LLLT in pain control after TB.

Combination of two desensitizing protocols to control dentin hypersensitivity in non-carious lesions: a randomized, double-blind clinical trial.

OBJECTIVES: This study evaluated the effect of photobiomodulation (PBM) combined with 8% strontium acetate (SA8%) in the treatment of dentin hypersensitivity (DH) in non-carious lesions and analyzed the risk factors with the patient's quality of life. METHODS: Eighty teeth with DH were randomly allocated into four treatment groups (n = 20): G1, PBM imitation + toothpaste with no active ingredient; G2, PBM imitation + toothpaste with SA8%; G3, PBM + toothpaste without the active ingredient; and G4, PBM + toothpaste with SA8%. Participants were provided with a questionnaire on the experience of dentin hypersensitivity (QEDH) to assess the impact of desensitizing treatment on health-related quality of life (HRQL). Friedman and Kruskal-Wallis tests were used for intra- and intergroup comparisons, and Wilcoxon and Mann-Whitney tests were used to analyze HRQL. All analyses used significance levels of 5%. RESULTS: Intergroup comparisons revealed a significant difference (p < 0.05); G4 had the best response in terms of HD reduction in G4 compared to the other groups on the 7th day of assessment (T3). Only G4 showed a statistically significant difference (p < 0.05) in the reduction of EDH for intragroup analysis. CONCLUSION: The combination of therapies was more effective in reducing DH than the isolated use of these strategies. CLINICAL RELEVANCE: The combination of therapies is effective in the treatment of DH.

Combination of strontium chloride and photobiomodulation in the control of tooth sensitivity post-bleaching: A split-mouth randomized clinical trial.

OBJECTIVE: This split-mouth randomized controlled clinical trial assessed the effect of 10% strontium chloride in combination with photobiomodulation (PBM) for the control of tooth sensitivity (TS) post-bleaching. METHODS: The upper/lower, right and left quadrants of fifty volunteers were randomized and allocated to four groups (n = 25): PLACEBO-placebo gel + simulation of PBM; Placebo + PBM; STRONTIUM-10% strontium chloride + simulation of PBM; and PBM + STRONTIUM-10% strontium chloride + PBM. All groups received tooth bleaching treatment with 35% hydrogen peroxide. For the PBM treatment, the laser tip was positioned in the apical and cervical regions of the teeth bleached in the respective hemi-arch. The laser system was operated in continuous mode, using 1.7 J of energy. A dose of 60 J/cm2 was applied to each point for 16 seconds under 808 nm near-infrared light (100mW of power), with a point area of 0.028 cm2. TS was assessed during a 21-day follow-up, using the modified visual analogue scale. RESULTS: In the intragroup assessment, the Friedman test indicated that PBM + STRONTIUM promoted the greatest reduction in TS after the second week of treatment (p ≤ 0.05). The Wilcoxon-Mann-Whitney test indicated that the groups Placebo + PBM, STRONTIUM, and STRONTIUM + PBM did not differ statistically (p ≥ 0.05) in the first and third weeks of treatment The group PLACEBO exhibited the greatest TS in the first three days after each bleaching session. CONCLUSION: The combination of 10% strontium chloride with PBM was effective in reducing post-bleaching TS; however, the combination of 10% strontium chloride with PBM was effective in reducing post-bleaching TS; however, it did not differ from the individual use of Placebo + PBM or STRONTIUM groups assessed after 21 days of follow-up.