Department of Biomaterials and Oral Biology, University of São Paulo -USP, São Paulo, Brazil; Department of Prosthodontics and Dental Materials, Meridional Faculty - IMED, Passo Fundo, Brazil.
Department of Prosthodontics and Dental Materials, Meridional Faculty - IMED, Passo Fundo, Brazil.
J Dent. 2018 Jun;73:50-56. doi: 10.1016/j.jdent.2018.04.002. Epub 2018 Apr 6.
The use of thio-urethane oligomers has been shown to significantly improve the mechanical properties of resin cements (RCs). The aim of this study was to use thio-urethane-modified RC to potentially reinforce the porcelain-RC structure and to improve the bond strength to zirconia and lithium disilicate.
Six oligomers were synthesized by combining thiols - pentaerythritol tetra-3-mercaptopropionate (PETMP, P) or trimethylol-tris-3-mercaptopropionate (TMP, T) - with di-functional isocyanates - 1,6-Hexanediol-diissocyante (HDDI) (aliphatic, AL) or 1,3-bis(1-isocyanato-1-methylethyl)benzene (BDI) (aromatic, AR) or Dicyclohexylmethane 4,4'-Diisocyanate (HMDI) (cyclic, CC). Thio-urethanes (20 wt%) were added to a BisGMA/UDMA/TEGDMA organic matrix. Filler was introduced at 60 wt%. The microshear bond strength (μSBS), Weibull modulus (m), and failure pattern of RCs bonded to zirconia (ZR) and lithium disilicate (LD) ceramics was evaluated. Biaxial flexural test and fractographic analysis of porcelain discs bonded to RCs were also performed. The biaxial flexural strength (σ) and m were calculated in the tensile surfaces of porcelain and RC structures (Z = 0 and Z = -t, respectively).
The μSBS was improved with RCs formulated with oligomers P_AL or T_AL bonded to LD and P_AL, P_AR or T_CC bonded to zirconia in comparison to controls. Mixed failures predominated in all groups. σ had superior values at Z = 0 with RCs formulated with oligomers P_AL, P_AR, T_AL, or T_CC in comparison to control; σ increased with all RCs composed by thio-urethanes at Z = -t. Fractographic analysis revealed all fracture origins at Z = 0.
The use of specific thio-urethane oligomers as components of RCs increased both the biaxial flexural strength of the porcelain-RC structure and the μSBS to LD and ZR.
The current investigation suggests that it is possible to reinforce the porcelain-RC pair and obtain higher bond strength to LD and ZR with RCs formulated with selected types of thio-urethane oligomers.
硫代尿烷低聚物的使用已被证明能显著提高树脂水门汀（RC）的机械性能。本研究的目的是使用硫代尿烷改性 RC 来增强瓷-RC 结构，并提高对氧化锆和锂硅玻璃陶瓷的粘结强度。
通过将硫醇 - 季戊四醇四 - 3-巯基丙酸酯（PETMP，P）或三羟甲基丙烷三 - 3-巯基丙酸酯（TMP，T）与二官能异氰酸酯 - 1,6-己二醇二异氰酸酯（HDDI）（脂肪族，AL）或 1,3-双（1-异氰酸根合-1-甲基乙基）苯（BDI）（芳香族，AR）或二环己基甲烷 4,4'-二异氰酸酯（HMDI）（环状，CC）相结合，合成了六种低聚物。硫代尿烷（20wt%）被添加到 BisGMA/UDMA/TEGDMA 有机基质中。填充料的添加量为 60wt%。评估了与氧化锆（ZR）和锂硅玻璃陶瓷（LD）陶瓷粘结的 RC 的微剪切粘结强度（μSBS）、Weibull 模数（m）和失效模式。还对与 RC 粘结的瓷盘进行了双轴弯曲试验和断口分析。分别在瓷层和 RC 结构的拉伸表面（Z=0 和 Z=-t）计算了双轴弯曲强度（σ）和 m。
与对照组相比，用低聚物 P_AL 或 T_AL 配方的 RC 与 LD 粘结，用 P_AL、P_AR 或 T_CC 配方的 RC 与氧化锆粘结，μSBS 得到了提高。所有组均以混合失效为主。与对照组相比，用低聚物 P_AL、P_AR、T_AL 或 T_CC 配方的 RC 在 Z=0 时具有更高的σ值；用所有含有硫代尿烷的 RC 在 Z=-t 时σ值增加。断口分析显示 Z=0 时所有断裂起源均在 RC 中。
作为 RC 成分的特定硫代尿烷低聚物的使用增加了瓷-RC 结构的双轴弯曲强度和与 LD 和 ZR 的 μSBS。
目前的研究表明，用选定类型的硫代尿烷低聚物配方的 RC，可以增强瓷-RC 对，提高与 LD 和 ZR 的粘结强度。
