Contraction stress of flowable composite materials and their efficacy as stress-relieving layers
Contraction stress of flowable composite materials and their efficacy as stress-relieving layers
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DOI：
10.14219/jada.archive.2003.0258
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发表时间：
2003-06-01
影响因子：
3.9
通讯作者：
Ferracane, JL
中科院分区：
文献类型：
--
作者：
Braga, RR;Hilton, TJ;Ferracane, JL
背景作者比较了可流动树脂基复合材料产生的聚合收缩应力与不可流动复合材料产生的应力值。他们还测量了通过将可流动复合材料的预固化层放置在不可流动复合材料下所产生的应力减小。作者首先在张力计中测试了四种可流动和六种不可流动复合材料的收缩应力。在研究的第二部分中，他们应用了一层1.4毫米厚的可流动复合材料或未填充树脂，并在测试设备中对其进行预固化，以评估低模量材料在后续高度填充复合材料层的光固化过程中产生的应力释放。通过三点弯曲试验测定预固化材料的弯曲模量。应力值范围在6.04至9.10兆帕斯卡之间。作者发现可流动和不可流动复合材料之间的应力没有显着差异。微填充复合材料产生较低的收缩应力比杂交。可流动复合材料的弯曲模量在4.1和8.2 GPa之间变化。关于复合材料预固化层对收缩应力的影响，作者观察到仅使用一种可流动材料和未填充树脂时收缩应力显著降低。可流动的复合材料产生的应力水平与不可流动的材料相似。大多数的流动材料测试没有产生显着的应力减少时，使用下nonflowable复合材料。临床意义。使用可流动的树脂基复合材料作为修复材料不太可能减少聚合应力的影响。当在不可流动复合材料下的薄层中使用时，应力减小取决于衬里材料的弹性模量。
Background. The authors compared the polymerization contraction stress produced by flowable resin-based composites with stress values produced by nonflowable composites. They also measured the stress reduction produced by placing a precured layer of flowable composite under a nonflowable composite.Methods. The authors first tested four flowable and six nonflowable composite materials for contraction stress in a tensiometer. In the second part of the study they applied a 1.4-millimeter-thick layer of flowable composite or unfilled resin and precured it in the test apparatus to assess the stress relief produced by a low-modulus material during light curing of a subsequent layer of highly filled composite. Flexural moduli of the precured materials were determined via a three-point bending test.Results. The stress values ranged between 6.04 and 9.10 megapascals. The authors found no significant differences in stress between flowable and nonflowable composites. Microfilled composites produced lower contraction stress than did hybrids. The flexural modulus of the flowable composites varied between 4.1 and 8.2 GPa. Regarding the effect of a precured layer of composite on contraction stress, the authors observed significant reductions with only one of the flowable materials and with the unfilled resin.Conclusions. The flowable composites produced stress levels similar to those of nonflowable materials. Most of the flowable materials tested did not produce significant stress reductions when used under a nonflowable composite.Clinical Implications. Using a flowable resin-based composite as a restorative material is not likely to reduce the effects of polymerization stress. When used in a thin layer under a nonflowable composite, the stress reduction depended on the elastic modulus of the lining material.