The aim of this study was to evaluate the cytotoxic effect, degree of conversion (% DC), Vickers hardness (VH), and surface morphology of composite resins. Eleven resins, nine bulk-fill resins, and two conventional resins were evaluated. Each material was sampled to evaluate DC (using FTIR), VH, cytotoxicity (using MTT and Neutral Red -NR test), surface morphology (using SEM and AFM), and organic filler (using EDS). All statistical tests were performed with SPSS and the level of significance was set at 0.05. MTT revealed that the materials presented low or no cytotoxic potential in relation to the control. Opus was the resin with the lowest cell viability at a 1:2 concentration at 72 h (32%) and at 7 days (43%), but that significantly increased when the NR test was applied at a 1:2 concentration after 7 days. Thickness and surface subjected to polymerization had no influence on DC, and differences were observed only between the materials. In the microhardness test, statistical differences were observed between the evaluated thicknesses. The bulk-fill resins analyzed in this study exhibited low and/or no cytotoxicity to L929 cells, except for Opus, which showed moderate cytotoxicity according to the MTT assay. When the NR test was used, results were not satisfactory for all composites, indicating the need for different methodologies to evaluate the properties of these materials. The assessed resins demonstrated acceptable physicomechanical properties.

Objective: The aim of the present study was to compare the effect of pre-treating dentin with chlorhexidine, at concentrations of 0.2% and 2%, and remineralizing paste containing CPP-ACP (MI Paste – GC) on the bond strength of adhesive systems. Material and methods: In total, 80 slides of dentin were used. These slides were 2 mm thick and were obtained from bovine incisors. Standard cavities were created using diamond bur number 3131. In the control groups, a Scotchbond Universal Adhesive (SUA) self-etching adhesive system of 3M ESPE and a Clearfil SE Bond (CSE) adhesive system of Kuraray were applied, following the manufacturer’s instructions. In the other groups, dentin was pretreated with chlorhexidine (0.2% and 2%) for 1 min and with MI Paste for 3 min. The cavities were restored with Z350 XT resin (3M ESPE). After 24 h of storage, the push-out test was applied at a speed of 0.5 mm/min. Results: The different dentin pretreatment techniques did not affect the intra-adhesive bond strength. There was a difference between treatment with MI Paste and chlorhexidine 0.2% in favor of the SUA, with values of 15.22 and 20.25 Mpa, respectively. Conclusions: The different pretreatment methods did not alter the immediate bond strength to dentin. Differences were only recorded when comparing the adhesives.

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Objective To measure the bond strength to zirconia subjected to different surface treatments of universal bonding agents. Materials and methods Eighty blocks of zirconia were obtained by CAD/CAM milling. The blocks were embedded into PVC tubes, polished sequentially with increasing granulation sandpapers and divided into two groups according to surface treatment: polished or grit‐blasted with alumina particles. Each group was then subdivided by bonding agent employed: Z‐Prime Plus (control); Scotchbond Universal; All Bond Universal; and Z‐Prime Plus + All Bond Universal. Cylindrical composite resin build‐ups were constructed atop the blocks using a two‐part metal die. Specimens were stored for 24 hours and subjected to microshear bond strength testing. Statistical analyses were performed by means of the F‐test (ANOVA), Student's t and Tukey's test. After sputter coating, zirconia surfaces and adhesive interfaces were analyzed by scanning electron microscopy (SEM). Results Bond strength was superior for grit‐blasted zirconia. In specimens with this surface treatment, there were no significant differences between experimental groups. On SEM, blasted surfaces exhibited areas of micromechanical retention and adhesive interfaces exhibited areas of zirconia‐adhesive interlocking. Conclusion Universal adhesive systems were able to bond to zirconia. The interlocking promoted by grit‐blasting enhanced bond strength. Clinical significance Universal adhesive systems simplify bonding to zirconia and enable intraoral repair of fractures.

Introduction Despite advances and innovations in restorative dentistry, microleakage remains one of the main problems in this area. Objective To evaluate in vitro marginal microleakage of Bulk Fill resins in class II cavities, with cervical termination in the dentin. Material and method Cavities, standardized on the mesial and distal surfaces, were prepared in forty top molars and randomly assigned to four groups (n = 10), according to the resin used. G1 (control): Filtek Z350 (3M/ESPE); G2: Filtek Bulk Fill flow (3M/ESPE); G3: Surefill SDR (Dentsply); G4: X-tra (Voco). These were further subdivided into subgroups according to the strategy used to apply the adhesive (self-etch technique and conventional). After storage for 24 hours in an oven (37 °C), the samples were submitted to the thermocycling test (500 cycles: 5 °C/55 °C). They were later waterproofed, immersed in Basic Fuchsin (0.5%) and sectioned in the mesial-distal direction for evaluation using a stereo magnifying glass at 40X (Coleman) Scores from 0 to 3 were assigned according to the microinfiltration observed. The Mann-Whitney and Kruskal-Wallis tests, with a significance level of 5%, were used for statistical analysis. Result There was no statistically significant difference between the Bulk Fill resins when the total acid-etching technique was used. Only the Filtek Bulk fill flow resin presented statistically significant results when the application of the adhesive system strategy was considered, with worse results, in relation to other groups, when it the self-etching strategy was considered. Conclusion The degree of leakage of the bulk fill resins studied, in class II cavities, was not influenced by the method of application of the adhesive system (conventional or two-step self-etching bonding agent), except for the Filtek Bulk fill flow.

Objective To assess the bond strength to dentin of the Single Bond (3M ESPE) and XP Bond (Dentsply) total-etch and Adper SE Plus (3M ESPE) self-etch adhesive systems. MethodsFifteen healthy human third molars were randomly allocated across three different groups of five teeth each according to the adhesive system. The occlusal portion of each tooth was removed under refrigeration using a flexible diamond disc (EXTEC, Enfield, CT, USA) down to an area of dentin that did not reveal enamel, as confirmed under a 40X stereo microscope (Ramsor, São Paulo, Brazil RESUMO ObjetivoAvaliar o grau de resistência de união à dentina dos sistemas adesivos de condicionamento ácido total Adper Single Bond (3M ESPE) e XP Bond (Dentsply) e autocondicionante Adper SE Plus (3M ESPE). MétodosQuinze terceiros molares humanos hígidos foram utilizados, divididos aleatoriamente em três grupos de cinco dentes cada, conforme o adesivo que seria utilizado. A porção oclusal foi removida com o auxílio de um disco flexível diamantado sob refrigeração, até expor uma área de dentina que não apresentasse ilhas de esmalte, comprovado em lupa esterioscópica em aumento de 40X. A smear layer foi padronizada em lixa d'água n°600. Na sequência os sistemas adesivos foram aplicados conforme as recomendações do fabricante, exceto o Adper SE Plus que teve seu tempo de polimerização triplicado. Sobre os dentes preparados foram construídos blocos de resina composta com 5mm de altura. As amostras foram armazenadas por 24 horas a 37°C em água destilada. Utilizando o disco flexível diamantado, foram obtidos corpos de prova com formato de palitos com área adesiva menor que 1mm². Em seguida o teste de microtração foi realizado numa Máquina de Ensaios Universal numa velocidade de 0,5 mm/min. Foram utilizados o teste ANOVA e comparações pareadas de Tukey. ResultadosOs valores da resistência de união para cada sistema adesivo em Mpa foram: 96,24 (XP Bond); 72,39 (Adper Single Bond) e 49,91 (Adper SE Plus). ConclusãoDessa forma, em relação à resistência de união à dentina, os adesivos convencionais apresentaram desempenho superior ao autocondicionante. Bond strength to dentin of total-etch and self-etch adhesive systemsResistência de união à dentina de sistemas adesivos convencionais e autocondicionante

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Aim:The aim of this study is to evaluate and compare root canal transportation, centering ability, and amount of dentin removed after root instrumentation with different rotary and reciprocating systems, using micro-computed tomography (micro-CT). Materials and methods: Forty curved mesial canals of lower molars were selected and divided into four experimental groups (n = 10) according to the system used: protaper next (PTN), wave one gold (WOG), prodesign logic (LOG), and vortex blue (VTX). The roots were scanned before and after instrumentation using micro-CT, with a 16 μm isotropic resolution. Results: Data were statistically analyzed using the Bioestat and the significance level was set at 0.05. For canal transportation, no significant differences were verified between the groups at 6 mm or 9 mm from the apex. At the apical third, LOG had a smaller mesial deviation when compared with PTN. A significant difference was found at the apical and coronal thirds, though with LOG having the best centering ability at the apical third and the worst one at the coronal third. All systems caused a greater wear at the coronal third (9 mm), decreasing at the apical one (3 mm), with statistically significant differences. LOG removed less dentin from the apical third (3 mm) than did the other instruments. Conclusion:The systems evaluated presented different results for canal transportation, centering ability, and dentin removal at each third. Clinical significance: The systems were evaluated together to evaluate neither the marked dental deviations nor the long-term signifiers of the databases and they were evaluated within the limits of normality. Therefore, they can be used without risks of embrittlement of the dental roots.