Lopez Carolina, Nizami Bushra, Robles Augusto, Gummadi Snigdha, Lawson Nathaniel C
Private Practice, Bogota 110110, Colombia.
Division of Biomaterials, School of Dentistry, University of Alabama at Birmingham School of Dentistry, Birmingham, AL 35209, USA.
Materials (Basel). 2024 Aug 6;17(16):3901. doi: 10.3390/ma17163901.
Filler content in dental composites is credited for affecting its physical and mechanical properties. This study evaluated the correlation between the filler percentage and strength, modulus, shrinkage stress, depth of cure, translucency and radiopacity of commercially available high- and low-viscosity dental composites. Filler weight percentage (wt%) was determined through the burned ash technique (800 °C for 15 min). Three-point bend flexural strength and modulus were measured according to ISO 4049 with 2 mm × 2 mm × 25 mm bars. Shrinkage stress was evaluated using a universal testing machine in which composite was polymerized through two transparent acrylic rods 2 mm apart. Shrinkage was measured from the maximum force following 500 s. The translucency parameter (TP) was measured as the difference in color (ΔE00) of 1 mm thick specimens against white and black tiles. The depth of cure was measured according to ISO 4049 in a cylindrical metal mold (4 mm diameter) with a 10 s cure. Radiopacity was measured by taking a digital X-ray (70 kVp for 0.32 s at 400 mm distance) of 1 mm thick specimens and comparing the radiopacity to an aluminum step wedge using image analysis software. The correlation between the filler wt% and properties was measured by Pearson's correlation coefficient using SPSS. There was a positive linear correlation between the filler wt% and modulus (r = 0.78, < 0.01), flexural strength (r = 0.46, < 0.01) and radiopacity (r = 0.36, < 0.01) and negative correlation with translucency (r = -0.29, < 0.01). Filler wt% best predicts the modulus and strength and, to a lesser extent, the radiopacity and translucency. All but two of the high- and low-viscosity composites from the same manufacturer had statistically equivalent strengths as each other; however, the high-viscosity materials almost always had a statistically higher modulus. For two of the flowable composites measured from the same manufacturer (3M and Dentsply), there was a lower shrinkage stress in the bulk-fill version of the material but not for the other two manufacturers (Ivoclar and Tokuyama). All flowable bulk-fill composites achieved a deeper depth of cure than the flowable composite from the same manufacturer other than Omnichroma Flow Bulk.
牙科复合材料中的填料被认为会影响其物理和机械性能。本研究评估了市售高粘度和低粘度牙科复合材料的填料百分比与强度、模量、收缩应力、固化深度、半透明度和射线不透性之间的相关性。通过灼烧灰分技术（800℃，15分钟）测定填料重量百分比（wt%）。根据ISO 4049标准，使用2mm×2mm×25mm的棒材测量三点弯曲挠曲强度和模量。使用万能试验机评估收缩应力，其中复合材料通过两根相距2mm的透明丙烯酸棒进行聚合。在500秒后的最大力处测量收缩率。半透明度参数（TP）通过测量1mm厚的试样相对于白色和黑色瓷砖的颜色差异（ΔE00）来确定。根据ISO 4049标准，在圆柱形金属模具（直径4mm）中进行10秒固化来测量固化深度。通过对1mm厚的试样进行数字X射线摄影（70kVp，400mm距离下曝光0.32秒）并使用图像分析软件将射线不透性与铝阶梯楔形块进行比较来测量射线不透性。使用SPSS软件通过Pearson相关系数测量填料wt%与性能之间的相关性。填料wt%与模量（r = 0.78，P < 0.01）、挠曲强度（r = 0.46，P < 0.01）和射线不透性（r = 0.36，P < 0.01）呈正线性相关，与半透明度呈负相关（r = -0.29，P < 0.01）。填料wt%最能预测模量和强度，在较小程度上也能预测射线不透性和半透明度。来自同一制造商的高粘度和低粘度复合材料中，除了两种之外，其他所有复合材料的强度在统计学上彼此相当；然而，高粘度材料的模量几乎总是在统计学上更高。对于从同一制造商（3M和登士柏）测量的两种可流动复合材料，材料的大容量填充版本的收缩应力较低，但其他两个制造商（义获嘉和德山）的情况并非如此。除了Omnichroma Flow Bulk之外，所有可流动大容量填充复合材料的固化深度都比来自同一制造商的松可流动复合材料更深。
