ABSTRACT
Introduction: Bonding to crystalline zirconia is currently a challenge. Properly cured adhesives are crucial to optimize this bond, and that in turn is influenced by the initial mobility of the system, as well as by the reactivity of the initiators. Aim: This study aimed to characterize adhesives containing monomer mixtures of different viscosities and double and triple photoinitiator systems; and to evaluate the bonding to Y-TZP zirconia, when adhesives were light-activated with monowave or polywave light-curing units (LCU). Materials and methods: Adhesives were formulated at a 1:1 weight proportion of Bis-GMA/TEGDMA or Bis-GMA/Bis-EMA. To these mixtures 0.5 wt% of CQ, 0.5-1.0 wt% of DABE, 0.5-1.0 wt% of DPIHP, or 0.5-1.0 wt% of TAS-Sb were added and used as photoinitiator systems. A total of ten adhesives were prepared. Resin composite cylinders were cemented on zirconia slices and 6000 thermal cycles were performed. Degree of conversion (DC), sorption (SO) and solubility (SL) after 7 days of water storage, and microshear bond strength (µSBS) were evaluated. Data were analyzed with three-way ANOVA and Tukey's HSD (α = 0.05). Results: Bis-GMA/Bis-EMA combined with either CQ/DABE or CQ/DABE/TAS-Sb presented the highest DC, and no significant differences were observed for LCUs (p = .298). CQ/DABE < CQ/DABE/TAS-Sb ≈ CQ/DABE/DPIHP and the polywave LCU showed smaller overall SO (p < .05). Bis-GMA/TEGDMA with CQ/DABE cured with the polywave LCU presented the lowest SO. SL varied as follows: CQ/DABE/TAS-Sb < CQ/DABE/DPIHP < CQ/DABE (p < .001). For µSBS, only the factor photoinitiator system was significant (p = .045). All mean values were above 30 MPa, with higher values being observed for BIS-GMA/TEGDMA and CQ/DABE. Conclusion: It can be concluded that the adhesive containing CQ/DABE/TAS-Sb as coinitiator of Bis-GMA/Bis-EMA mixtures produced a material with higher DC and lower SL, while bond strength values were similar to the ones obtained by CQ/DABE.
ABSTRACT
Propósito: Avaliar a influência de diferentes concentrações do 10-MDP no grau de conversão (%GC) de adesivos experimentais (AE) em diferentes protocolos de manipulação (PM). Material e Métodos: Os AE contêm um sistema iniciador triplo (CQ/DABE/sal diodônio) e diferentes concentrações de 10-MDP A1 = 0%, A2 = 3%, A3 = 6%, A4 = 9%, A5 = 12% ou A6 = 15% em peso foram adicionadas. Um adesivo comercialmente disponível foi utilizado para comparação (Ambar, FGM). Os adesivos foram divididos em 4 PM: I) Controle (sem manipulação), II) 5 s de evaporação, III) 20 s de evaporação e IV) adição de água. O GC foi avliado com o FTIR-ATR. Os dados foram analisados com Anova a dois critérios e Tukey (α = 0,05). Resultados: Diferenças significativas foram encontradas entre os adesivos (p < 0.0001) e PM (p = 0.000001). Também foi encontrado um efeito de interação (p < 0.0001). Para os adesivos, foi observado que o A5 obteve o maior resultado (89.70% ± 4.21) e o com menor valor foi o AE sem MDP (76.35% ± 8.45). O Ambar obteve valores intermediários (83.68% ± 9.46). Para o PM, o maior valor foi para: Controle (88.50% ± 2.72) > 20-s-evaporação (85.13% ± 6.95) ≈ 5-s-evaporação (85.18% ± 6.08) ≈ adição de água (85.80% ± 10.33). Conclusão: Os resultados obtidos sugerem que o 10- MDP pode aumentar a %GC dos AE com o sistema iniciador triplo.(AU)
Purpose: To evaluate the influence of different concentrations of 10-MDP in degree of conversion (%DC) of experimental adhesives (EA) applied with different manipulation protocols (MP). Materials and Methods: EA containing a three-component-photoinitiator system (CQ/DABE/iodonium salt) were prepared and different concentrations of 10-MDP were added A1 = 0%, A2 = 3%, A3 = 6%, A4 = 9%, A5 = 12%, or A6 = 15% by weight. A commercially available adhesive was used as comparison (Ambar, FGM). The adhesives were divided into 4 MP: I) Control (without any manipulation), II) 5 s of evaporation, III) 20 s of evaporation and IV) addition of water to the adhesive. DC was evaluated by FTIR-ATR. The data were analyzed with two-way Anova and Tukey´s HSD (α = 0.05). Results: Significant differences were found between the adhesives (p < 0.0001) and MP (p = 0.000001). An interaction effect (p < 0.0001) was also observed. For adhesives, it was observed that the A5 showed the highest value (89.70% ± 4.21) and the lowest values to EA without MDP (76.35% ± 8.45). Ambar showed intermediate values (83.68% ± 9.46). For MP, the highest DC was observed to Control (88.50% ± 2.72) > 20-s-evaporation (85.13% ± 6.95) ≈ 5-s-evaporation (85.18% ± 6.08) ≈ addition of water (85.80% ± 10.33). Conclusion: The results suggest that 10- MDP can enhance the %DC of the threecomponent- photoinitiator system EAs evaluated.(AU)
