Papadogiannis D Y, Lakes R S, Papadogiannis Y, Palaghias G, Helvatjoglu-Antoniades M
University of Athens, School of Dentistry, Department of Biomaterials, Greece.
Dent Mater. 2008 Feb;24(2):257-66. doi: 10.1016/j.dental.2007.05.009. Epub 2007 Jul 20.
The purpose of this study was to examine the viscoelastic properties of nanofilled dental composites under both static and dynamic testing and to determine the influence of temperature, medium of storage and storage time.
Three nanofilled composites, one packable and one ormocer were tested. The specimens were examined dry at 21 degrees C and wet at 21, 37 and 50 degrees C after being stored for 24h and 1 month under both static and dynamic testing. Shear modulus, elastic modulus, loss tangent, Poisson's ratio and other viscoelastic parameters were calculated. Data were analyzed with one-way and two-way analysis of variance (ANOVA) (p=0.05).
All materials tested showed a significant decrease in their moduli with the increase of temperature, while the effect of water storage was different among the composites. Grandio was the composite with the highest Young's modulus followed by Filtek P60.
Most of the materials tested did not have elastic moduli near to that of dentin, making them less satisfactory in posterior restorations. The materials possessing nanosized filler particles had different elastic properties among them and this implies that filler size is not the only factor that affects the elastic behavior of dental composites.
本研究旨在通过静态和动态测试来检测纳米填充牙科复合材料的粘弹性特性，并确定温度、储存介质和储存时间的影响。
测试了三种纳米填充复合材料，一种可压实型和一种有机陶瓷型。在静态和动态测试条件下，将样本分别在储存24小时和1个月后，于21℃干燥状态下以及在21℃、37℃和50℃潮湿状态下进行检测。计算剪切模量、弹性模量、损耗角正切、泊松比和其他粘弹性参数。数据采用单向和双向方差分析（ANOVA）进行分析（p = 0.05）。
所有测试材料的模量均随温度升高而显著降低，而复合材料在储水后的影响各不相同。Grandio是杨氏模量最高的复合材料，其次是Filtek P60。
大多数测试材料的弹性模量与牙本质的弹性模量相差较大，这使得它们在后牙修复中不太令人满意。含有纳米级填料颗粒的材料之间具有不同的弹性特性，这意味着填料尺寸不是影响牙科复合材料弹性行为的唯一因素。
