Abstract：
OBJECTIVE: This study investigated the influence of photoinitiator types on degree of conversion (DC), rate of polymerization (RP), flexural strength (FS), flexural modulus (FM), and light transmittance (LT) of filled and unfilled light-curable resin cements through different thicknesses and shades of lithium disilicate ceramics.
METHODS: Lithium disilicate ceramic discs (IPS Emax Press, background [0.0], 0.5, 1.0, 2.0, 3.0, and 4.0 mm, shades A1 and BL3) were prepared. Experimental resin-based cements [TEGDMA/BisGMA (50/50 mass%)] were prepared using either camphorquinone (CQ)/amine (0.44/1.85 mol%) or TPO (0.44 mol%)], and a micro and nanofiller loads of nil (unfilled); 40/10 mass%; and 50/10 mass%). Resin cements (0.2 mm thick) were placed on the lower surface of the ceramic specimens and light-activated for 30 s from the upper surface using a Bluephase Style curing light (exitance at tip: 1236 mW/cm2 ± 1.20). LT and distribution of irradiance through the ceramics were measured using a UV-vis spectrometer and a beam profile camera, respectively (n = 3). The DC and RP were measured in real-time using mid infrared spectroscopy in attenuated total reflectance (ATR) mode (n = 3). FS and FM were measured using a universal testing machine (n = 5). Statistical analyses were performed on LT, DC, RP, FS, and FM data using a general linear model, and supplementary ANOVA and post hoc Tukey multiple comparison test were also performed (α = .05).
RESULTS: Thicknesses, shades, photoinitiator type, and fillers load significantly influenced the optical and mechanical characteristics of the resin-based materials (p < 0.05). The BL3 shade ceramic provided higher values of DC, RP, FS, FM, and LT compared with the A1 shade (p < 0.05). Increasing ceramic thickness decreased the properties of the resin-based materials (p < 0.05). Generally, TPO improved mechanical properties of the resin cement compared with CQ (p < 0.05).
CONCLUSIONS: The luting process of indirect restorations may be improved by using high molar absorptivity, more reactive, and more efficient photoinitiators such as TPO, as opposed to conventional CQ. The use of such initiator may allow the placement of thicker and more opaque indirect restorations.
METHODS: Lithium disilicate ceramic discs (IPS Emax Press, background [0.0], 0.5, 1.0, 2.0, 3.0, and 4.0 mm, shades A1 and BL3) were prepared. Experimental resin-based cements [TEGDMA/BisGMA (50/50 mass%)] were prepared using either camphorquinone (CQ)/amine (0.44/1.85 mol%) or TPO (0.44 mol%)], and a micro and nanofiller loads of nil (unfilled); 40/10 mass%; and 50/10 mass%). Resin cements (0.2 mm thick) were placed on the lower surface of the ceramic specimens and light-activated for 30 s from the upper surface using a Bluephase Style curing light (exitance at tip: 1236 mW/cm2 ± 1.20). LT and distribution of irradiance through the ceramics were measured using a UV-vis spectrometer and a beam profile camera, respectively (n = 3). The DC and RP were measured in real-time using mid infrared spectroscopy in attenuated total reflectance (ATR) mode (n = 3). FS and FM were measured using a universal testing machine (n = 5). Statistical analyses were performed on LT, DC, RP, FS, and FM data using a general linear model, and supplementary ANOVA and post hoc Tukey multiple comparison test were also performed (α = .05).
RESULTS: Thicknesses, shades, photoinitiator type, and fillers load significantly influenced the optical and mechanical characteristics of the resin-based materials (p < 0.05). The BL3 shade ceramic provided higher values of DC, RP, FS, FM, and LT compared with the A1 shade (p < 0.05). Increasing ceramic thickness decreased the properties of the resin-based materials (p < 0.05). Generally, TPO improved mechanical properties of the resin cement compared with CQ (p < 0.05).
CONCLUSIONS: The luting process of indirect restorations may be improved by using high molar absorptivity, more reactive, and more efficient photoinitiators such as TPO, as opposed to conventional CQ. The use of such initiator may allow the placement of thicker and more opaque indirect restorations.
摘要：
目的：本研究考察了光引发剂类型对转化度（DC）的影响，聚合速率（RP），抗弯强度(FS),弯曲模量（FM），通过不同厚度和色调的二硅酸锂陶瓷，填充和未填充的光固化树脂水泥的透光率（LT）。
方法：二硅酸锂陶瓷盘（IPSEmax压力机，背景[0.0]，0.5、1.0、2.0、3.0和4.0mm，制备阴影A1和BL3)。实验树脂基水泥[TEGDMA/BisGMA(50/50质量%)]使用樟脑醌(CQ)/胺(0.44/1.85摩尔%)或TPO(0.44摩尔%)制备。以及为零(未填充)的微米和纳米填料负载;40/10质量%;和50/10质量%)。将树脂粘固剂(0.2mm厚)放置在陶瓷样品的下表面上,并使用蓝相固化光(尖端处的激发:1236mW/cm2±1.20)从上表面光活化30s。使用UV-vis光谱仪和光束轮廓相机测量通过陶瓷的LT和辐照度分布，分别（n=3）。使用中红外光谱法在衰减全反射(ATR)模式下实时测量DC和RP(n=3)。使用通用试验机(n=5)测量FS和FM。对LT进行了统计分析，DC,RP,FS,和调频数据使用一般的线性模型，还进行了补充方差分析和事后Tukey多重比较检验(α=0.05)。
结果：厚度，阴影，光引发剂类型,和填料负载显著影响树脂基材料的光学和机械特性(p<0.05)。BL3灯罩陶瓷提供了更高的DC值，RP,FS,FM,和LT与A1阴影相比(p<0.05)。增加陶瓷厚度降低了树脂基材料的性能(p<0.05)。一般来说,与CQ相比，TPO提高了树脂水泥的力学性能（p<0.05）。
结论：使用高摩尔吸光系数可以改善间接修复的过程，更多的反应，和更有效的光引发剂，如TPO，与传统的CQ相反。使用这种引发剂可以允许放置更厚和更不透明的间接修复体。
方法：二硅酸锂陶瓷盘（IPSEmax压力机，背景[0.0]，0.5、1.0、2.0、3.0和4.0mm，制备阴影A1和BL3)。实验树脂基水泥[TEGDMA/BisGMA(50/50质量%)]使用樟脑醌(CQ)/胺(0.44/1.85摩尔%)或TPO(0.44摩尔%)制备。以及为零(未填充)的微米和纳米填料负载;40/10质量%;和50/10质量%)。将树脂粘固剂(0.2mm厚)放置在陶瓷样品的下表面上,并使用蓝相固化光(尖端处的激发:1236mW/cm2±1.20)从上表面光活化30s。使用UV-vis光谱仪和光束轮廓相机测量通过陶瓷的LT和辐照度分布，分别（n=3）。使用中红外光谱法在衰减全反射(ATR)模式下实时测量DC和RP(n=3)。使用通用试验机(n=5)测量FS和FM。对LT进行了统计分析，DC,RP,FS,和调频数据使用一般的线性模型，还进行了补充方差分析和事后Tukey多重比较检验(α=0.05)。
结果：厚度，阴影，光引发剂类型,和填料负载显著影响树脂基材料的光学和机械特性(p<0.05)。BL3灯罩陶瓷提供了更高的DC值，RP,FS,FM,和LT与A1阴影相比(p<0.05)。增加陶瓷厚度降低了树脂基材料的性能(p<0.05)。一般来说,与CQ相比，TPO提高了树脂水泥的力学性能（p<0.05）。
结论：使用高摩尔吸光系数可以改善间接修复的过程，更多的反应，和更有效的光引发剂，如TPO，与传统的CQ相反。使用这种引发剂可以允许放置更厚和更不透明的间接修复体。
