ABSTRACT Objective: This study assessed whether the use of a silane coupling agent influence the bond strength of two universal adhesives to ceramic or resin CAD/CAM blocks. Methods: Forty-eight samples were obtained from each resin nano-ceramic hybrid block (RCBs) and lithium disilicate ceramic blocks (LD). Samples were treated with silane with MDP (Monobond - S-MDP), silane without MDP (Prosil - PS), and no silane application (Control - Ctr) followed by universal adhesive with silane (UAS) and without silane (UA) (n=8). Three polyurethane tubes (1.5 mm of internal diameter) were positioned in each sample treated surface and filled with a dual cured resin cement. Bond strength was assessed by microshear bond strength test and failure analysis was performed for all samples. Results: For the RCBs, UAS presented the highest bond strength values (p=0.004). Silane application was not significant in bond strength values (p=0.444). For LD, silane application was significant in bond strength values (p<0.001), but the adhesive was not (p=0.066). Failure analysis showed high prevalence of adhesive failures for both substrates. Conclusion: A silane-containing universal adhesive promoted the best bond strength results to the resin nano-ceramic hybrid block. For bonding to a glass-ceramic CAD/CAM material, additional silane (without MDP) application presented the best results.

RESUMO Objetivo: Este estudo avaliou se o uso de um agente de união silano influencia na resistência de união de dois adesivos universais a blocos CAD/CAM cerâmicos ou resinosos. Métodos: Quarenta e oito amostras foram obtidas de blocos resinosos (RCBs) e cerâmicos de dissilicato de lítio (LD). As amostras foram tratadas com silano contendo: MDP (Monobond - S-MDP), silano sem MDP (Prosil - PS) ou sem aplicação de silano (Control - Ctr) seguido de adesivo universal com silano (UAS) ou sem silano (UA) (n=8). Três tubos de poliuretano (1,5 mm de diâmetro interno) foram posicionados em cada superfície tratada da amostra e preenchidos com um cimento resinoso dual. A resistência de união foi avaliada pelo teste de microcisalhamento e a análise de falha foi realizada para todas as amostras. Resultados: Para os RCBs, UAS apresentou os maiores valores de resistência de união (p=0,004). A aplicação de silano não foi significativa nos valores de resistência adesiva (p=0,444). Para LD, a aplicação de silano foi significativa nos valores de resistência de união (p<0,001), mas o adesivo não (p=0,066). A análise de falhas mostrou alta prevalência de falhas adesivas para ambos os substratos. Conclusão: O adesivo universal contendo silano promoveu os melhores valores de resistência adesiva ao bloco de resina. Para o bloco cerâmico, a aplicação adicional de silano (sem MDP) apresentou melhores resultados.

Abstract Objective This study aimed to evaluate whether the use of desensitizing dentifrices containing obliterating agents can affect bond strength of eroded/abraded dentin. Methodology A total of 100 dentin samples were obtained from human molars. The teeth were cut into 3 mm-thickness discs and allocated in five groups (n=20), according to the toothpaste used: WoF – abrasion with fluoride-free toothpaste (Cocoricó); Arg – toothpaste containing arginine (Colgate Sensitive Pro-Relief); Nov – calcium sodium phosphosilicate toothpaste (Sensodyne Repair and Protect); SnF – fluoride-containing toothpaste (AmF/SnCl2/SnF2 – Elmex Erosion); and Control (no erosive/abrasive process). The erosive/abrasive cycle consisted of immersion in citric acid (1%, pH 2.6, 5 min, 4×/day) and abrasion (2×/day, 120–20 sec abrasion, 100 sec immersion) with each toothpaste. During intervals, samples were immersed in artificial saliva. This cycle was performed for five days. Two resin cylinders (2 mm in diameter) were constructed on each sample for the shear bond strength test using a universal adhesive system. The self-etch and etch-and-rinse (Scotchbond Universal) strategies were employed, each in half of the total sample (n=10). Bond strength (MPa) was measured in a shear test and failure modes were assessed with a stereomicroscope. Statistical analysis was performed using the two-way analysis of variance (ANOVA) and Tukey tests (p<0.05). Results A statistically significant difference was found between the adhesive strategies tested (p<0.001), with the self-etching form showing higher values than the etch-and-rinse. Moreover, no significant differences were observed between the tested toothpastes (p=0.750) and interactions (p=0.438). Conclusion The use of toothpaste containing obliterating agents does not affect bond strength to dentin subjected to erosive/abrasive conditions when a universal adhesive is used. However, the self-etch strategy might be preferred for eroded/abraded dentin.

Abstract Objective To evaluate the effect of a toothpaste containing calcium silicate/sodium phosphate/fluoride associated or not to the boost serum (BS) against erosive tooth wear (ETW) on enamel and dentin. Methodology Bovine enamel and dentin specimens were subjected to an erosion-abrasion cycling model (1% citric acid - pH 3.6 -2 min / artificial saliva – 60 min, 4×/day, 5 days). Toothbrushing was performed for 15 s (2 min exposed to slurry), 2×/day, with the toothpastes (n=10): control without fluoride (Weleda), Arg/Ca/MFP (Colgate Pro-Relief), Si/PO4/MFP (Regenerate-Unilever), and Si/PO4/MFP/BS (Si/PO4/MFP with dual BS – Advanced Enamel Serum-Unilever). The effect of treatments on the eroded tissues was assessed by surface microhardness in the first day, and surface loss (SL) resulting from ETW was evaluated by profilometry (μm) after three and five days. Additional dentin specimens (n=5/group) were subjected to 20,000 brushing cycles to verify the abrasivity of the toothpastes. Data were subjected to ANOVA and correlation tests (5%). Results For enamel, no difference in microhardness was observed among the treated groups, and similar SL was obtained after 5 days. For dentin, Si/PO4/MFP/BS resulted in higher microhardness values, but none of the groups presented significantly lower SL than the control. There was no significant correlation between SL and abrasiveness. Conclusion The calcium silicate/sodium phosphate toothpaste and serum increased microhardness of eroded dentin, but they did not significantly reduce enamel and dentin loss compared to the non-fluoride control toothpaste. The abrasiveness of the toothpastes could not predict their effect on ETW.

Resumo O objetivo desse estudo foi avaliar o grau de conversão, estabilidade de cor, composição química e resistência de união de um cimento resinoso fotoativado contaminado com três soluções hemostáticas diferentes. Foram preparadas amostras para o grupo controle (cimento não contaminado) e grupos experimentais (cimento contaminado com uma das soluções hemostáticas) de acordo com os testes. Para o grau de conversão e análise de cor (n=10), as amostras (3 mm de diâmetro e 2 mm de espessura) foram avaliadas por espectroscopia de infravermelho com transformação de Fourier (FTIR) e espectrofotometria CIELAB (L*, A*, B*), respectivamente. Para a análise química elementar (n=1), os espécimes (2 mm de espessura e 6 mm de diâmetro) foram avaliados por espectroscopia de energia dispersiva de raios-x (EDS). As resistências de união dos grupos foram avaliadas pelo ensaio de microcisalhamento (n=20) em um substrato cerâmico de vidro reforçado com leucita, seguida da análise de modo de falha por microscopia eletrônica de varredura (MEV). Os valores médios, com exceção da avaliação química e do modo de falha, foram avaliados por ANOVA e pelo teste de Tukey. A estabilidade de cor foi influenciada pelo tempo de armazenagem (p<0,001) e interação entre a contaminação e o tempo (p<0,001). A contaminação pelo Hemostop e Viscostat Clear não influenciaram no GC, porém a contaminação com Viscostat aumentou o GC. A resistência de união do cimento a cerâmica foi negativamente afetada pelos contaminantes (p<0,001). A contaminação por agentes hemostáticos afetou a resistência de união, o grau de conversão e a estabilidade de cor do cimento resinoso fotoativado testado.

Abstract The aim of this study was to evaluate the degree of conversion, color stability, chemical composition, and bond strength of a light-cured resin cement contaminated with three different hemostatic solutions. Specimens were prepared for the control (uncontaminated resin cement) and experimental groups (resin cement contaminated with one of the hemostatic solutions) according to the tests. For degree of conversion, DC (n = 5) and color analyses (n = 10), specimens (3 mm in diameter and 2 mm thick) were evaluated by Fourier transform infrared spectroscopy (FTIR) and CIELAB spectrophotometry (L*, a*, b*), respectively. For elemental chemical analysis (n = 1), specimens (2 mm thick and 6 mm in diameter) were evaluated by x-ray energy-dispersive spectroscopy (EDS). The bond strengths of the groups were assessed by the microshear test (n = 20) in a leucite-reinforced glass ceramic substrate, followed by failure mode analysis by scanning electron microscopy (SEM). The mean values, except for the elemental chemical evaluation and failure mode, were evaluated by ANOVA and Tukey’s HSD test. The color stability was influenced by storage time (p<0.001) and interaction between contamination and storage time (p<0.001). Hemostop and Viscostat Clear contamination did not affect the DC, however Viscostat increased the DC. Bond strength of the resin cement to ceramic was negatively affected by the contaminants (p<0.001). Contamination by hemostatic agents affected the bond strength, degree of conversion, and color stability of the light-cured resin cement tested.