Veiga de Almeida University, School of Dentistry, Rio de Janeiro, RJ, Brazil.
Federal Fluminense University, School of Dentistry, Niterói, RJ, Brazil.
Dent Mater. 2021 Jun;37(6):1046-1053. doi: 10.1016/j.dental.2021.03.003. Epub 2021 Apr 14.
To propose monomer formulations that show an optimal degree of conversion as a function of depth for bulk-fill applications.
Four resin blends were formulated with methacrylate-based monomers: BisGMA + TEGDMA (control); BisEMA + BisGMA + TEGDMA (BisEMA-based); UDMA + BisGMA + TEGDMA (UDMA-based) and BisEMA + UDMA + BisGMA + TEGDMA (BisEMA + UDMA-based). For each material, a photoinitiating system and silanized filler particles were added. The rheological analyses were performed with a rotational rheometer using the cone/plate geometry. CIELab coordinates were assessed over black and white backgrounds using a bench spectrophotometer (SP60, X-Rite) to calculate the translucency parameter (TP) for samples with 0.5, 4, and 6 mm thickness. The degree of CC conversion (DC) was determined by infrared spectroscopy (FTIR/ATR) at 0.05 mm (top), 4, and 6 mm depths (bottom), and the bottom-to-top ratio was considered. A broad spectrum-based LED was used for light activation. Analysis of variance and Tukey's test (95%) were performed on the results.
The materials tested showed pseudoplastic and thixotropic behavior and a predominance of viscous effects over elastics. The control resin yielded the lowest viscosity for the entire shear rate investigated, followed by the BisEMA-based, BisEMA + UDMA-based, and UDMA-based group, which had the highest viscosity. The UDMA-based material showed the lowest TP as a function of thickness. Both the materials' formulations and depths significantly influenced the DC. The UDMA-based group promoted the highest DC on the top (71 ± 1%) and 4 mm depth (68 ± 1%) but exhibited lower bottom-to-top DC ratio. The BisEMA + UDMA-based material promoted the highest bottom-to-top DC ratio at 4 mm (99%) and 6 mm (97%).
The resin matrix interferes in the rheological behavior, translucency parameter, and polymerization capacity as a function of depth. The material formulated with the addition of UDMA and BisEMA demonstrated the highest curing potential as a function of depth and can be useful for bulk-fill applications.
提出单体配方，使其在作为体填充应用的函数的深度上显示出最佳的转化率。
用基于甲基丙烯酸酯的单体配制了四种树脂混合物：BisGMA + TEGDMA（对照）；BisEMA + BisGMA + TEGDMA（基于 BisEMA）；UDMA + BisGMA + TEGDMA（基于 UDMA）和 BisEMA + UDMA + BisGMA + TEGDMA（基于 BisEMA + UDMA）。对于每种材料，都添加了光引发剂系统和硅烷化填料颗粒。使用旋转流变仪，使用锥板几何形状进行流变分析。使用台式分光光度计（SP60，X-Rite）在黑色和白色背景下评估 CIELab 坐标，以计算厚度为 0.5、4 和 6mm 的样品的半透明度参数（TP）。通过傅里叶变换红外光谱（FTIR/ATR）在 0.05mm（顶部）、4mm 和 6mm（底部）深度处测定 CC 转化率（DC），并考虑底部到顶部的比例。使用广谱 LED 进行光激活。对结果进行方差分析和 Tukey 检验（95%）。
所测试的材料表现出假塑性和触变性，粘性效应明显超过弹性效应。对照树脂在整个剪切速率范围内表现出最低的粘度，其次是基于 BisEMA、基于 BisEMA + UDMA 和基于 UDMA 的组，它们的粘度最高。基于 UDMA 的材料表现出最低的 TP 作为厚度的函数。材料配方和深度都显著影响 DC。基于 UDMA 的组在顶部（71±1%）和 4mm 深度（68±1%）处促进了最高的 DC，但表现出较低的底部到顶部 DC 比。基于 BisEMA + UDMA 的材料在 4mm（99%）和 6mm（97%）处促进了最高的底部到顶部 DC 比。
树脂基质会干扰流变行为、半透明度参数和聚合能力作为深度的函数。添加 UDMA 和 BisEMA 的材料配方表现出最高的固化潜力作为深度的函数，可用于体填充应用。
