固化灯及照射距离对纳米树脂显微硬度的影响

Microhardness evaluation of a nano-composite resin light-cured with halogen light and light-emitting diode at 3 different distances

目的观察在不同照射距离下,不同固化模式对复合树脂表面显微硬度的影响。方法将复合树脂制备成直径4mm,厚2mm的圆片状实验模块,根据照射距离(2mm、5mm、10mm)与固化模式(430mw/cm2卤素灯40秒与860mw/cm2二极管固化灯20秒)分成6组,每组6个,共36个。固化后用硬度计测定每个树脂块顶面与底面的韦氏硬度值。统计分析各组间显微硬度值的差别。结果随照射距离增大,树脂块显微硬度显著降低(p<0.01);各组树脂块顶面显微硬度值均高于底面(p<0.01);在2mm与5mm照射距离下,不同固化方式对树脂块表面硬度无显著影响(p>0.05);在10mm照射距离下,二极管固化灯组底面的显微硬度显著高于卤素灯组(p<0.01)。结论远距离照射下,要使深层复合树脂充分固化应选择高功率的固化模式。

Objective To evaluate the influence of light curing mode on the microhardness of composite resin at different curing distances. Methods Thirty-six composite resin Z350 specimens （diameter： 4ram and thickness： 2mm） were divided into 6 groups （ n = 6 ） and polymerized with convention halogen light curing （ 430mw/cm^2, 40s ） and lightemitting diodes （860 mW/cm^2 ,20s）. Vicker＇s microhardness of each specimen was obtained on the top and bottom surfaces using a microhardness Tester. Results As the curing distance increased, the microhardness of each specimen decreased significantly （P 〈 0. 01 ）. Top surfaces showed significantly higher microhardness than bottom surfaces in all specimens （P 〈 0. 01 ）. At 10mm curing distance,the microhardness of the bottom surfaces of light-emitting diodes group were significantly higher than that of the halogen light group（ P 〈 0. 01 ）. While at 2mm and 5mm curing distance, no significant difference was found（p 〉 0. 05）, Conclusion Under long distance radiation, high power light-emitting diodes is superior to the halogen light for a better microhardness of composite resin.