Introduction The attachment of fiberglass posts is achieved through an adhesive process. Failures in adhesion may occur due to the hydrolytic degradation of the adhesives, or to the degradation of the collagen fibres of the hybrid layer by intrinsic enzymes. Objective To evaluate the effect of chlorhexidine and sodium hypochlorite treatment on bond strength to dentin. Material and method Thirty bovine roots were randomly distributed into 3 groups (n=10): a) Control, b) 2% Chlorhexidine, and c) 5% Sodium Hypochlorite. Next, RelyX® ARC resin cement was used to cement the post. Each specimen resulted in samples from the three root thirds that were submitted to the pushout test (MPa) at 24 hours and 12 months. Bond strength values were analysed using the Kolmogorov-Smirnov, 3-way ANOVA and Tukey tests. The fracture mode of the pin was also analysed using stereomicroscopy. Result There were no significant differences between treatments at the immediate time (p=0.0644) or in the interaction of factors (p=0.1935). After one year, the experimental groups showed no significant differences in bond strength in relation to the control group, with the exception of the cervical third of the chlorohexidine group in which there was a significant loss of adhesion. As for the fracture mode, there was a predominance of the mixed type in all groups and thirds. Conclusion The use of chlorhexidine or hypochlorite provides neither benefits nor losses in the adhesive bond strength of fiberglass posts. However, there is an influence of the root thirds, with the worst bond strength in the apical third.

RESUMO | O presente relato de caso clínico descreve uma abordagem conservadora para otimização de facetas diretas em resina composta. Para melhoria da anatomia e textura superficial das restaurações antigas, o tratamento baseou-se em um protocolo previsível e reprodutível de acabamento e polimento, o qual garantiu a obtenção de um sorriso equilibrado sem expor a paciente ao ciclo restaurador repetitivo. Inicialmente, a estratégia consistiu na remoção dos excessos de resina, definindo a anatomia primária dos dentes, seguindo a definição dos sulcos verticais e horizontais para mimetizar as características superficiais naturais, proporcionando superfície mais estética e favorável à reflexão de luz. Em adição, o polimento foi conduzido de modo a obter restaurações lisas e brilhantes, que proporcionam maior longevidade aos tratamentos restauradores estéticos. DESCRITORES | Acabamento; Polimento; Resina composta; Estética.ABSTRACT | Protocol of finishing, texturing and polishing for direct composite resin restorations • This clinical case report describes a conservative approach to optimize the composite resin direct veneer. In order to improve the anatomy and surface texture of previous restorations, the treatment was based on a predictable and reproducible finishing and polishing protocol which ensured a harmonic smile without exposing the patient to a repetitive restorative cycle. Firstly, the strategy consisted of removing excess resin, thus defining the primary anatomy of the teeth, following the definition of the vertical and horizontal grooves to mimic the natural surface characteristics, providing an aesthetic surface, favorable to light reflection. In addition, polishing was conducted in order to obtain smooth and shiny restorations, which provide greater longevity to the aesthetic restorative treatments.

Resumo Introdução Com o avanço estético e tecnológico dos compósitos restauradores diretos, a procura pela Odontologia Éstética tem aumentado. Objetivo Avaliar o manchamento e a rugosidade superficial dos compósitos Filtek Z350 (3M ESPE) e Filtek Bulk Fill (3M ESPE), polidos por diferentes sistemas: Disco SofLex e Disco SofLex diamantado espiral (ambos da 3M ESPE), após exposição repetitiva ao café. Material e método Neste estudo in vitro, um total de 80 discos de resina foi confeccionado, com 40 espécimes para cada compósito avaliado. Os espécimes foram ainda subdivididos em grupos (n=10) de acordo com o método de polimento ‒ SofLex e SofLex diamantado ‒ e a solução de armazenamento ‒ água deionizada (controle) e café (experimental). Após 24 horas de armazenamento em água deionizada, foi realizada a avaliação de cor e rugosidade inicial, bem como a execução dos protocolos de polimento testados. Posteriormente, os espécimes foram expostos ao processo de manchamento em café e água deionizada durante 42 dias. Após esse período, a cor e a rugosidade foram reavaliadas. Resultado A análise estatística paramétrica evidenciou que o manchamento superficial foi influenciado significativamente pelos fatores compósito e solução, mas não pelo fator polidor ou ainda por qualquer interação entre os fatores. Para o fator compósito, Filtek Z350 exibiu maior manchamento, e para o fator solução, foi observado maior manchamento para o café. Já na análise de rugosidade, não houve diferenças significativas. Conclusão Independentemente do sistema de polimento, a solução experimental de café alterou a cor de ambos os compósitos avaliados e verificou-se que a rugosidade não foi alterada.

This study evaluated the effect of the material thickness on shrinkage stress and bottom-to-top hardness ratio of conventional and bulk-fill composites. Six commercial composites were selected based on their different technologies: Two conventional (C1, C2), two high-viscosity bulk-fill (HVB1, HVB2), and two low-viscosity bulkfill (LVB1, LVB2). Shrinkage stress was analyzed for five specimens with 2 mm thickness (C-factor 0.75 and volume 24 mm 3 ) and five specimens with 4 mm thickness (C-factor 0.375 and volume 48 mm 3 ) for 300 s in a universal testing machine.Bottom-to-top hardness ratio values were obtained from Knoop microhardness measurements in specimens with 2-and 4-mm thickness (n = 5). Thickness increase resulted in significantly higher shrinkage stress for all materials with the exception of HVB2 and LVB1. C1, C2, HVB2, and LVB1 showed lower bottom-to-top hardness ratios at 4 mm than at 2 mm. Only LVB2 presented a bottom-to-top hardness ratio lower than 80% at 2 mm, while HVB1 surpassed this threshold at 4 mm of depth.The results suggest that the increase of composite thickness affected the shrinkage stress values. Also, thickness increase resulted in lower bottom-to-top hardness ratio. HVB1 showed better behavior than other bulk-fill materials, with low stress and adequate bottom-to-top hardness ratio at 4 mm thickness.

Aim: Using dietary supplements may affect the properties of composite resins due to their acidic pH. The present in vitro study aimed to assess the surface roughness and color stability of two composite resins - nanohybrid (Empress Direct) and nanoparticulate (Filtek Z350) - after prolonged exposure to dietary supplements. Methods: We produced 30 specimens from each composite (8x2-mm discs) and divided them into six groups (n=10). After the initial measurement of the surface properties (roughness and color), we exposed the specimens to a degradation process in Maltodextrin and Whey Protein for 22.5 and 7.5 days, respectively, using deionized water as the control solution. At the end of 22.5 days, we reassessed the specimens. After verifying data normality with the Kolmogorov-Smirnov test, we performed ANOVA followed by Tukey’s test at 5%. Results: We found significant differences for materials immersed in the Whey Protein solution (p<0.05). The roughness of Empress Direct was higher (0.45+0.07) than Filtek Z350 (0.22+0.05). The composites tested also showed color change (ΔE>3.3) after the immersion period (p<0.001). In Maltodextrin, the Empress Direct group presented (4.52+1.23) and Filtek Z350 (4.04+0.66), while after immersion in Whey Protein, they showed (5.34+1.68) and (4.26+1.02), respectively. Conclusion: Sports drinks changed the surface roughness and color stability of the composite resins studied. The Filtek Z350 group showed lower color variation than the Empress Direct composite in both solutions evaluated.

Objectives: Resin composites containing surface pre-reacted glass (S-PRG) were introduced to reduce demineralization and improve remineralization of the tooth structure. However, water diffusion within the material is necessary for its action, which can impair its overall physical-mechanical properties over time, including the color stability. This study aimed to evaluate the color stability and related degree of conversion (DC) of four resin composites.Materials and Methods: Discs (n=5/group) of microhybrid, nanofilled, nanohybrid, and S-PRG-based nanohybrid composites with two opacities were prepared. Color (CIELab and CIEDE2000) was evaluated after aging in grape juice. The DC was analyzed by using Fourier Transform Infrared Spectroscopy before and after photopolymerization. Data were statistically analyzed by using two-way analysis of variance and post-hoc least significant difference tests (P<.05).Results: In the color stabilityanalysis, the interaction between filler type and opacity was significant. S-PRG influenced color stability and DC.Conclusions: The nanohybrid resin composite presented favorable color stability and a greater DC, which is likely related to its organic content. S-PRG based nanohybrid resins require caution since its bioactive benefits depends on interaction with the environment that can be prone to impair color stability.Clinical Relevance: As color stability is mandatoryin specific regions, staining can jeopardize the esthetics of a resin composite. The use of nanohybrid composites with no or reduced BisGMA content and diluents may be more appropriate in these areas. Since materials containing S-PRG can offer relevant benefits, professionals need to balance their higher susceptibility to staining favoring other relevant properties.

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