冷热循环对硬衬材料颜色及挠曲强度影响的研究

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

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。

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.