Department of Restorative Dentistry, Dental School of the Ludwig-Maximilians-University, Goethestr. 70, 80336, Munich, Germany.
Clin Oral Investig. 2013 Jan;17(1):185-93. doi: 10.1007/s00784-012-0689-1. Epub 2012 Mar 6.
Clinical data indicate an increased trend in material fracture as reason for failure in composite restorations, questioning whether modern resin-based composites (RBCs) are able to fulfil the rising aesthetical demands and to provide at the same time a sufficient mechanical stability also in larger cavities. Nano-hybrid RBCs are promoted as materials with improved mechanical properties. The aim of this study was to analyse differences in mechanical properties within and between modern flowable and non-flowable nano-hybrid and micro-hybrid RBCs by measuring mechanical properties at macro- and micro-scale.
Thirty-four RBCs with traditional and new monomer formulation or photo-polymerization initiator technology-15 nano-hybrid, nine micro-hybrid and ten flowable-were therefore considered. Flexural strength, flexural modulus (E(flexural)), indentation modulus, Vickers hardness (HV) and creep were measured after the samples had been stored in water for 24 h at 37°C. Differences within the materials as well as within material categories were statistically analysed using one-way ANOVA with Tukey HSD post hoc test (α = 0.05) as well as partial eta-square statistics.
The category of micro- and nano-hybrid RBCs performed in all properties superior compared to the flowable RBCs. The former two categories differ significantly only with regard to three parameters, with nano-hybrid RBCs showing higher HV respectively lower E(flexural) and filler weight. The micro-mechanical parameters proved to be more sensitive to differences in filler amount and RBCs type than the macro-mechanical properties.
Only few differences were found between nano-hybrid and micro-hybrid RBCs as a material category and thus, from laboratory tests, no clear advantages in the mechanical stability in stress-bearing areas of nano-hybrid RBCs are expected clinically. Similar is valid for materials with new monomer formulation or photo-polymerization initiator technology. However, several of the measured nano-hybrid RBCs showed consistently higher mechanical properties than the mean values of the micro-hybrid RBCs.
临床数据表明，复合材料修复体的材料断裂率呈上升趋势，这令人质疑现代树脂基复合材料（RBC）是否能够满足日益增长的美学需求，并在较大的腔体内提供足够的机械稳定性。纳米混合 RBC 被认为是具有改善机械性能的材料。本研究的目的是通过测量宏观和微观尺度上的机械性能，分析现代流动型和非流动型纳米混合和微混合 RBC 之间的机械性能差异。
因此，考虑了 34 种具有传统和新型单体配方或光聚合引发剂技术的 RBC，包括 15 种纳米混合、9 种微混合和 10 种流动型。在 37°C 水中储存 24 小时后，测量弯曲强度、弯曲模量（E（flexural））、压痕模量、维氏硬度（HV）和蠕变。使用单向方差分析和 Tukey HSD 事后检验（α=0.05）以及偏 eta 平方统计对材料内和材料类别内的差异进行统计学分析。
微混合和纳米混合 RBC 类别在所有性能上均优于流动型 RBC。前两类仅在三个参数上存在显著差异，纳米混合 RBC 的 HV 较高，E（flexural）和填料重量较低。微观力学参数比宏观力学性能更能敏感地反映填料量和 RBC 类型的差异。
纳米混合和微混合 RBC 作为材料类别之间仅发现了很少的差异，因此，从实验室测试来看，预计在承重区域的机械稳定性方面，纳米混合 RBC 没有明显的优势。具有新型单体配方或光聚合引发剂技术的材料也是如此。然而，一些测量的纳米混合 RBC 显示出的机械性能始终高于微混合 RBC 的平均值。
