The changes reported herein might influence the selection of the dental materials and will bring new knowledge in this field to prevent radiation-related caries in root dentin.

No abstract

The objective of this systematic review was to determine the influence of surface treatment of glass fiber posts on bond strength to dentine. Laboratory studies were searched in MEDLINE, PubMed, Embase, PubMed Central, Scopus, and Web of Science search engine. All authors interdependently screened all identified articles for eligibility. The included studies were assessed for bias. Because of the considerable heterogeneity of the studies, a meta-analysis was not possible. Twelve articles were found eligible and included in the review. An assessment of the risk of bias in the included studies provided a result that classified the studies as low, medium, and high risk of bias. The available evidence indicated that the coronal region of the root canal bonded better to the glass fiber post than apical regions. Phosphoric acid, hydrogen peroxide, and silane application enhance post's retentiveness. In light of the current evidence, surface treatment strategies increase the bond strength of glass fiber post to dentine. However, recommendations for standardized testing methods and reporting of future clinical studies are required to maintain clinically relevant information and to understand the effects of various surface treatment of glass fiber post and their bond strength with dentine walls of the root canal.

RESUMOAs restaurações de resinas compostas têm aumentado consideravelmente em popularidade e previsibilidade, possibilitando a realização de um tratamento odontológico minimamente invasivo. No entanto, para se obter o sucesso das restaurações de resina composta é necessário ter conhecimento dos materiais adesivos e da técnica de utilização, caso contrário os insucessos podem aparecer rapidamente. Assim, o objetivo deste trabalho foi realizar uma revisão de literatura sobre o desempenho clínico de diferentes tipos de resinas compostas e de sistemas adesivos no que se refere à longevidade. Para essa avaliação foram verificadas algumas características das restaurações logo após elas serem finalizadas e depois de um determinado tempo. Características como sensibilidade pós-operatória, cor, integridade marginal, cárie secundária, textura, adaptação marginal, retenção, deslocamento, descoloração marginal, forma anatômica, tiveram seus desempenhos comparados. A influência dos vários sistemas adesivos na longevidade das restaurações foi também observada em função da sua fundamental importância na união entre o dente e o material restaurador. Concluiu-se que a maioria das restaurações se apresentou clinicamente aceitável, quando se usou resinas compostas híbridas, nanoparticuladas ou microhíbridas e sistema adesivo convencional.

This in vitro study synthetized hybrid composite nanoparticles of graphene oxide (GO) and montmorillonite MMt (GO-MMt) by ultrasound treatments. Samples were characterized by X-ray diffraction, FT-Raman, FTIR, TEM and SEM. The effect of their incorporation (0.3% and 0.5%) on the mechanical properties in a resin-based composite (RBC) and their bioactivity potential were evaluated. The specimens were characterized by evaluating their 3-point flexural strength (n = 6), modulus of elasticity (n = 6), degree of conversion (n = 6), microhardness (n = 6), contact angle (n = 3) and SEM analysis (n = 3). In vitro test in SBF were conducted in the RBCs modified by the hybrid. Overall, the synthetized hybrid composite demonstrated that GO was intercalated with MMt, showing a more stable compound. ANOVA and Tukey test showed that RBC + 0.3% GO-MMt demonstrated superior values of flexural strength, followed by RBC + 0.5% GO-MMt (p < 0.05) and both materials showed higher values of microhardness. All groups presented a contact angle below 90°, characterizing hydrophilic materials. RBCs modified by the hybrid showed Ca and P deposition after 14 days in SBF. In conclusion, RBCs composed by the hybrid showed promising results in terms of mechanical properties and bioactive potential, extending the application of GO in dental materials.

<p>Objective: Composite polymerization shrinkage<br />stress is an inherent process of chemical and light<br />composite resin activation. Consequently, this fact has<br />been associated to potential clinical problems. The<br />aim of the present in vitro study was to evaluate the<br />volume and C-factor influence on chemical and lightcuring<br />composite resin polymerization shrinkage<br />stress, using a non-rigid method that thereby provides<br />lower stress values, causing a minimal deflection in<br />load cell. Materials and Methods: The contraction<br />forces of the Z-250 and Concise composite resins<br />during polymerization were recorded in an UTM in<br />two experiments. In the first experiment, the Z-250<br />composite was inserted beetwen two rectangular<br />steel plates (6.0 x 2.0 mm), varyng the resin volumes<br />and C-factors, in a single increment, polymerized for<br />20 s and the forces generated were recorded for 120<br />s. In the second experiment, a pair of rectangular steel<br />plates (3x2mm) and two square steel plates (2x2mm),<br />with varied heights (2; 3 mm, respectively), were<br />used to determine the C-factor (0.6; 0.3) influence.<br />Results: The polymerized Z-250 results showed that<br />the volume variations, independent of the C-factor,<br />had a direct influence on the shrinkage stress,<br />different from the Concise, which was influenced by<br />the C-factor. Conclusion: The present study showed<br />that a higher volume of composite resins determines<br />an increase in the shrinkage stress of light-curing<br />composites.</p><p><strong>Keywords</strong></p><p>C-factor. Composite resin. Polymerization. Shrinkage<br />stress.</p>

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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.