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|Title:||Effect of thickness of ceramic veneers on color stability and bond strength of resin luting cements containing alternative photoinitiators|
Delgado, Alex Jose
Coelho Sinhoreti, Mario Alexandre
Ramos Salles de Oliveira, Dayane Carvalho
|Abstract:||Purpose: To evaluate the light transmittance of ceramic veneers of different thicknesses and verify their influence on the degree of conversion, color stability, and dentin bond strength of light-curing resin cements containing different photoinitiator systems. Materials and Methods: Experimental resin cements were fabricated containing camphorquinone and amine (CQ-amine), TPO, Ivocerin (IVO), or TPO and Ivocerin (TPO-IVO). All photoinitiators were characterized by UV-Vis spectro-photometry. Disk-shaped lithium disilicate ceramic specimens that were 0.4, 0.7, and 1.5 mm in thickness were prepared using IPS e.max Press (Ivoclar Vivadent, shade LT/A2). Light transmittance through each specimen was measured using spectrophotometry. Specimens of each cement (n = 10) were made in a custom-designed mold and were light cured through each glass-ceramic disk using a multiwave LED (Bluephase G2, Ivoclar Vivadent). CS was evaluated using spectrophotometry before and after artificial aging with UV light. DC was evaluated using FTIR-spectroscopy. Dentin mu SBS was evaluated using 0.75-mm-thick specimens that were light cured under the same protocol (n = 10). All data were submitted to two-way ANOVA and Tukey's test (alpha = 0.05; beta = 0.2). Results: CQ-amine cements showed the highest color changes (p < 0.05) due to increased yellowing when compared to the amine-free cements (p < 0.05). However, all cements showed a significant color change after aging when cured through ceramics up to 1.5 mm thick (p < 0.05). The TPO-IVO cement showed the highest DC and the IVO cement showed a similar DC when compared to the CQ-amine cement. The TPO cement presented the lowest DC (p = 0.0377). No differences in mean dentin mu SBS were found among the cements, except for the TPO cement, which presented a lower mean dentin mu SBS (p = 0.0277). Conclusion: Amine-free cements containing Ivocerin and TPO seem to be a better alternative to CQ-amine cements, while not reducing either DC or dentin mu SBS of amine-free cements. However, CQ-amine and amine-free cements still seem to change color over time.|
|Appears in Collections:||FOP - Artigos e Outros Documentos|
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