冷热循环对硬衬材料颜色及挠曲强度影响的研究

目的 研究冷热循环对义齿硬衬材料的颜色稳定性及挠曲强度的影响。方法 制作热凝树脂材料(日进自然I型)试件(64 mm×10 mm×2 mm)32块,随机分成4组,每组8块试件。分别为热凝树脂衬垫对照组;热凝树脂衬垫实验组;自凝硬衬材料(德山Rebase Ⅱ Fast)对照组;自凝硬衬材料实验组。所有试件衬垫前先进行5 000次冷热循环,然后分别加衬上述2种衬垫材料,形成基托材料与衬垫材料复合体(64.0 mm×10.0 mm×3.3 mm),实验组再行5 000次冷热循环。通过L*a*b*值及三点加载实验,比较实验组与对照组的颜色和挠曲强度差异。结果 德山硬衬材料实验组与对照组b*值间有统计学差异,但2种衬垫材料颜色变化均在临床可接受范围内。4组基托-衬垫复合体间挠曲强度无统计学差异。结论 德山Re-base Ⅱ Fast是一种方便易用的衬垫材料。

Effects of thermal cycling on color stability and flexural strength of hard reliners

Objective To evaluate the effects of thermal cycling on the color stability and flexural strength of two hard reline materials.Methods 32 rectangular bars（64 mm×10 mm×2 mm） of heat-polymerized acrylic resin（Nissin Nature I） were fabricated and subjected to 5 000 thermal cycling（5-55 ℃） to stimulate the aging of base material.The reliner-base composites were fabricated by relining the rectangular bars with Tokuyama Rebase II Fast and Nissin Nature I respectively.The experiment groups were subjected to another 5 000 thermal cycling.The color stability was examined with a colorimeter and flexural strength was tested with the method of three-point flexural test on the control groups and experiment groups.Data were analyzed with SPSS 17.0.Results There was statistical difference in the b＊ values between Tokuyama-Nissin control group and Tokuyama-Nissin thermal cycling group,while ΔE values of Nissin-Nissin composites and Tokuyama-Nissin composites were clinically accepted.There was no statistical difference in flexural strength change among all four groups.Conclusions The Tokuyama Rebase II Fast can be used in clinic effectively and conveniently.