Curtis Andrew R, Palin William M, Fleming Garry J P, Shortall Adrian C C, Marquis Peter M
Biomaterials Unit, School of Dentistry, University of Birmingham, St. Chads Queensway, Birmingham B4 6NN, UK.
Dent Mater. 2009 Feb;25(2):188-97. doi: 10.1016/j.dental.2008.06.003. Epub 2008 Jul 24.
To determine the influence of nano-sized filler particles and agglomerates of nanoparticles ('nanoclusters') in resin-based composite (RBC) materials on the bi-axial flexure strength (BFS) following cyclic pre-loading and storage in a 'dry' or 'wet' environment.
Seven commercially available RBC restoratives, Heliomolar (Ivoclar Vivadent, Schaan, Liechtenstein), Z100 MP Restorative, Filtek Z250, Filtek Supreme (3M ESPE, St. Paul, MN, USA) in Body (FSB) and Translucent (FST) shades, Grandio and Grandio Flow (VOCO, Cuxhaven, Germany), containing differing filler particle types and morphologies were investigated. Specimens were pre-loaded at 20, 50 or 100 N for 2000 cycles and stored in a 'dry' or 'wet' environment prior to BFS testing.
A general linear model analysis of variance highlighted a reduction in the BFS following pre-loading, however, individual RBC materials responded differently. The RBCs containing agglomerated nano-sized particles or 'nanoclusters' (Filtek Supreme) demonstrated distinctive and unique patterns of response to pre-loading. Cyclic pre-loading at 20 and 50 N significantly increased the Weibull modulus of both FSB (8.53+/-1.91 and 10.23+/-2.29) and FST (16.89+/-3.78 and 10.91+/-2.45) compared with FSB and FST control (no pre-cyclic load) specimens (5.98+/-1.34 and 7.99+/-1.78, respectively). BFS of FSB and FST was maintained or significantly increased compared with the other materials following 20 and 50 N cyclic pre-load (P<0.05).
The 'nanoclusters' provided a distinct reinforcing mechanism compared with the microhybrid, microfill or nanohybrid RBC systems resulting in significant improvements to the strength and reliability, irrespective of the environmental storage and testing conditions. Silane infiltration within interstices of the nanoclusters may modify the response to pre-loading induced stress, thereby enhancing damage tolerance and providing the potential for improved clinical performance.
确定树脂基复合材料（RBC）中纳米级填料颗粒和纳米颗粒团聚体（“纳米团簇”）对在“干燥”或“潮湿”环境中循环预加载和储存后的双轴弯曲强度（BFS）的影响。
研究了七种市售的RBC修复材料，分别是Heliomolar（义获嘉伟瓦登特公司，沙恩，列支敦士登）、Z100 MP修复材料、Filtek Z250、Filtek Supreme（3M ESPE公司，圣保罗，明尼苏达州，美国）的实体色（FSB）和半透明色（FST）、Grandio和Grandio Flow（VOCO公司，库克斯港，德国），这些材料含有不同类型和形态的填料颗粒。在进行BFS测试之前，将试样分别以20、50或100 N的力预加载2000次循环，并储存在“干燥”或“潮湿”环境中。
方差的一般线性模型分析表明，预加载后BFS降低，然而，不同的RBC材料反应不同。含有团聚纳米级颗粒或“纳米团簇”的RBC（Filtek Supreme）对预加载表现出独特的响应模式。与FSB和FST对照（无预循环加载）试样（分别为5.98±1.34和7.99±1.78）相比，20 N和50 N的循环预加载显著提高了FSB（8.53±1.91和10.23±2.29）和FST（16.89±3.78和10.91±2.45）的威布尔模量。与其他材料相比，20 N和50 N循环预加载后，FSB和FST的BFS保持不变或显著提高（P<0.05）。
与微混合、微填料或纳米混合RBC系统相比，“纳米团簇”提供了一种独特的增强机制，无论环境储存和测试条件如何，都能显著提高强度和可靠性。纳米团簇间隙内的硅烷渗透可能会改变对预加载诱导应力的响应，从而提高损伤耐受性，并为改善临床性能提供潜力。
