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.

CLINICAL-THERAPEUTICAL MANAGEMENT OF EXPOSED PULP USING BIOACTIVE MATERIALS: TWO CASE REPORTS

Aims: This article present alternatives of bioactive materials use for direct pulp capping in immature teeth and for apexogenesis.Case report: Two case reports with the application of bioactive cementsare presented here: one in a tooth with pulp exposure and another with deep carious lesion, pulp exposure and open apex.Results: In both cases, the treatment was performed in one visit and a favorable clinical and radiographic follow-up was achieved.Conclusion: The use of bioactive materials ledto the formation of a dentin bridge and healing process in the pulp tissue exposure, without the need for conventional endodontic treatment

Fracture strength and hybrid layer formation of endodontically-treated teeth after dental bleaching photoactivated with violet LED.

OBJECTIVE: To evaluate in vitro the effect of dental bleaching using high concentration hydrogen peroxide (HP) photoactivated with violet LED on fracture strength and hybrid layer formation. METHODS: forty endodontically-treated bovine teeth were randomized into four groups (n = 10): C - Control, HP - 35% hydrogen peroxide, HP-BL - 35% hydrogen peroxide photoactivated with blue LED, HP-VL - 35% hydrogen peroxide photoactivated with violet LED. Three bleaching sessions with an interval of 7 days between them were performed. After 10 days of the last bleaching session, the dental crowns were restored and submitted to the fracture strength test. Five specimens from each group were used to evaluate the hybrid layer formation by scanning electron microscope (SEM) images. One-way ANOVA and Kruskal-Wallis test were used for parametric and non-parametric data, respectively. Significance level of 5% was adopted to all the tests. RESULTS: No differences on fracture strength among the groups were observed (p > 0.05). HP and HP-BL showed alterations on hybrid layer formation compared to C group (p < 0.05), but not for HP-VL (p > 0.05). No differences on hybrid layer formation were observed among HP, HP-VL and HP-BL groups (p > 0.05). CONCLUSION: Dental bleaching, photoactivated or not, did not affect the fracture strength of endodontically-treated teeth. Regardless of the protocol used, hydrogen peroxide altered the hybrid layer formation at some level when the restoration was placed after 10 days of the last bleaching session.

Effect of non-vital tooth bleaching photoactivated with blue or violet LED on color and microhardness.

BACKGROUND: To evaluate the efficacy of dental bleaching protocols using 35% hydrogen peroxide photoactivated with violet LED on color and microhardness of endodontically treated teeth. METHODS: Forty specimens were selected and randomized into 4 groups (n = 10): C - Control, HP - 35% hydrogen peroxide, HP + BL - 35% hydrogen peroxide + blue LED, HP + VL - 35% hydrogen peroxide + violet LED. Three bleaching sessions were performed for each group. Color analysis was performed 7 days after each bleaching session. Two-way repeated measure ANOVA and Bonferroni test were used to evaluate the effect of different bleaching protocols and evaluation times on the dependent variables (∆E and ∆L). Dentin microhardness was measured 24 h after the third bleaching session. Data were evaluated by ANOVA and Tukey's test at a significance level of 5%. RESULTS: Differences on ∆E and ∆L were verified after the first and second bleaching sessions (p < 0.05) and showed stability after the third one, for all the groups. No differences were observed among HP, HP + BL, and HP + VL groups, regardless of the evaluation time (p > 0.05). HP and C showed the greatest and smallest reduction in dentin microhardness (p < 0.05), respectively. No difference between HP + BL and HP + VL protocols (P > 0.05) was observed. CONCLUSIONS: High concentration hydrogen peroxide (35%) photoactivated with violet LED bleached endodontically treated teeth effectively. However, the same protocol negatively affected the dentin microhardness, but not in the same level of 35% HP solely used.

Whitening efficacy of low concentration hydrogen peroxide photoactivated with blue or violet LED.

BACKGROUND: Bleaching protocols using low concentration hydrogen peroxide (HP) photoactivated with LED sources have been widely discussed. Herein, we evaluated the whitening efficacy of 15% HP photoactivated with blue or violet LED compared to 35% HP. METHODS: Thirty bovine crowns were sectioned into 5 × 5 × 2 mm specimens. After staining in black tea, the specimens were randomized into three groups (n = 10): 35% HP, 15% HP + blue LED and 15% HP + violet LED. Two bleaching sessions were performed and the color assessment (∆L*, ∆a*, ∆b*, ∆Eab [CIELab], ∆E00 [CIEDE2000] and WID) was performed before, 24h after each session, 7 days and 1 month after the last session. Data were evaluated by two-way repeated measures ANOVA and Bonferroni post-test at a significance level of 5%. RESULTS: All groups showed effective and similar results over 1 month of follow-up (p > 0.05), with only intragroup differences among the time intervals (p < 0.05). CONCLUSIONS: The use of 15% HP photoactivated with blue or violet LED showed similar whitening efficacy compared to 35% HP. Thus, the association of low concentration bleaching gels with blue or violet LED sources can provide successful and less-aggressive treatment in terms of color change.

Hybrid layer formation and bond strength to dentin impregnated with endodontic sealer after cleaning protocols.

AIMS: This study evaluated the hybrid layer formation and bond strength of two adhesive systems, Scotchbond Universal (U) or Adper Scotchbond Multi Purpose (M), after cleaning protocols using ethanol (E) or xylol (X), to dentin impregnated with an epoxy-resin based endodontic sealer. SETTINGS AND DESIGN: The study design was an Experimental in vitro study. METHODOLOGY: One hundred bovine dentin specimens were randomly allocated into five groups (n = 10): Computed tomography (CT) (control): Only acid etching + M; E+U; X+U; E+M. After the specimen preparation, images were obtained using confocal laser scanning microscopy to evaluate the hybrid layer formation. For microshear bond strength test, the dentin specimens were included in polyvinyl chloride tubes and four resin composite cylinders were placed on the surface. The analysis was performed 24 h after storage. STATISTICAL ANALYSIS USED: For parametric and nonparametric data, analysis of variance followed by Tukey test and Kruskal-Wallis, followed by Dunn test were, respectively, used at a significance level of 5%. RESULTS: Regarding hybrid layer formation, all experimental groups were similar to each other (P > 0.05). However, CT showed higher hybrid layer formation than other groups (P < 0.05), except in relation to X+M (P > 0.05). Bond strength was statistically similar among all groups (P > 0.05). CONCLUSIONS: Hybrid layer formation in dentin impregnated with epoxy resin-based sealer and submitted to different cleaning protocols was similar to the control group only for X+M. No differences were found among the experimental groups. Regarding the bond strength, no effect was observed for any group.

Avaliação do efeito da água de piscina sobre a rugosidade superficial de resinas compostas de esmalte / Evaluation of the pool water effect on the surface roughness of enamel composite resins

Introdução: a estabilidade de cor e a durabilidade de uma restauração em resina composta são influenciadas por sua lisura superficial. Características inerentes ao material, procedimentos de acabamento e polimento, dieta e hábitos dos indivíduos podem interferir nas suas propriedades superficiais. Objetivo: avaliar a rugosidade superficial de resinas compostas de esmalte submetidas ao contato com água de piscina clorada e estimar se o uso de uma proteção mecânica limitaria esse contato e seus efeitos. Metodologia: duzentos corpos de prova, de cinco diferentes resinas foram preparados e distribuídos, aleatoriamente, em quatro grupos (n=10), de acordo com o desafio a que foram submetidos: imersão em água destilada sem e com proteção de moldeira de acetato; imersão em água clorada sem e com proteção de moldeira de acetato. Os corpos ficaram imersos por 30 dias, sendo as respectivas águas trocadas diariamente. Para avaliação da rugosidade superficial, utilizou-se um rugosímetro. Procedeu-se à análise estatística inferencial por meio da análise de variância a 3-critérios, avaliando-se a comparação múltipla dessas médias com auxílio do teste de Tukey (nível de significância de 5%). Resultados: observou-se: interação significativa entre os fatores água e condição experimental (p<0,0001) e maior rugosidade superficial para a resina Esthet-X HD, quando exposta à água clorada. O uso da moldeira resultou em maiores valores de rugosidade superficial para todas as resinas testadas quando expostas à água clorada. Conclusão: o efeito da água de piscina foi material dependente. O uso da proteção mecânica pareceu aumentar a rugosidade superficial das resinas compostas expostas à água clorada.

Introduction: the color stability and durability of a composite resin restoration are influenced by its surface smoothness. Characteristics inherent to the material, finishing and polishing procedures, diet and habits of individuals may interfere with their surface properties. Objective: to evaluate the surface roughness of enamel composite resins submitted to contact with chlorinated pool water and to estimate if the use of a mechanical protection would limit this contact and its effects. Methodology: two hundred specimens of five different resins were prepared and randomly distributed into four groups (n = 10), according to the challenge they were subjected to: immersion in distilled water, without and with acetate tray protection; immersion in chlorinated water, without and with acetate tray protection. The bodies were immersed for 30 days, and their waters were changed daily. To evaluate the surface roughness, a rugosimeter was used. Inferential statistical analysis was performed using 3-criteria analysis of variance, and a multiple comparison of these means was evaluated using Tukey's test (significance level of 5%). Results: it was observed a significant interaction between water and experimental conditions (p <0.0001) and greater surface roughness for Esthet-X HD resin when exposed to chlorinated water. The use of the tray resulted in higher surface roughness values for all the resins tested when exposed to chlorinated water. Conclusion: the effect of pool water was dependent material. The use of mechanical protection appeared to increase the surface roughness of composite resins exposed to chlorinated water.