Department of Biomaterials, King's College London Dental Institute, Floor 17, Guy's Tower, London Bridge, London SE1 9RT, UK.
Dent Mater. 2011 Apr;27(4):e51-9. doi: 10.1016/j.dental.2010.11.009. Epub 2010 Dec 9.
Cavity lining with flowable composites have been proposed to improve initial marginal adaptation and minimize shrinkage stresses. The purpose of this study was to evaluate if prewarming of composites would influence the flow and enhance marginal adaptation thus the effect of pre-warming different types of composites on their properties are reported.
Six different composites were used in this study including a flowable and a polyacid modified composite. Uncured composites were pressed between two glass plates with a known load and the film thickness was measured to determine flow. Polymerization shrinkage was measured by means of a one-dimension contacting transducer. Flexural strength was determined using a three-point bend test. Microleakage was determined in human lower third molars on both enamel and dentin restoration interfaces. Cytocompatibility was analyzed with an Alamar Blue redox cell proliferation assay. The flow properties, linear shrinkage, flexural strength, microleakage and cytocompatibility were evaluated at 22 °C and 60 °C.
The results indicated that the film thickness for each of the materials was significantly lower at 60 °C and the linear shrinkage was greater as a result of the higher degree of polymerization. The flexural strength of Spectrum TPH and Wave were found to be statistically significantly higher with pre-warming, however the other composites did not exhibit any differences. Microleakage studies showed that pre-warming had no significant bearing on the results and alamarBlue(®) results showed that the pre-heating did not have an effect on the cytotoxicity however the levels of cytotoxicity varied between the composites that can be attributed to the composition.
Pre-warming of the composites studied enhanced flow as observed by measuring film thickness and did not significantly affect other properties.
用可流动复合材料衬里空腔被提议用来改善初始边缘适应性并最小化收缩应力。本研究的目的是评估复合材料的预加热是否会影响其流动性并增强边缘适应性，因此报道了预加热不同类型的复合材料对其性能的影响。
本研究使用了六种不同的复合材料，包括一种可流动复合材料和一种聚酸改性复合材料。未固化的复合材料在已知载荷下被压在两块玻璃板之间，测量薄膜厚度以确定流动性。聚合收缩通过一维接触式换能器测量。通过三点弯曲试验测定弯曲强度。在人下颌第三磨牙的牙釉质和牙本质修复界面上测定微渗漏。使用 Alamar Blue 氧化还原细胞增殖测定法分析细胞相容性。在 22°C 和 60°C 下评估流动性能、线性收缩、弯曲强度、微渗漏和细胞相容性。
结果表明，每种材料的薄膜厚度在 60°C 时显著降低，聚合度较高导致线性收缩增大。Spectrum TPH 和 Wave 的弯曲强度随着预加热而显著提高，但其他复合材料则没有表现出任何差异。微渗漏研究表明预加热对结果没有显著影响，AlamarBlue（®）结果表明预加热对细胞毒性没有影响，然而细胞毒性水平在不同的复合材料之间存在差异，这可能归因于组成。
研究中复合材料的预加热增强了流动性，如通过测量薄膜厚度观察到的那样，并且对其他性能没有显著影响。
