三种光固化灯在不同照射距离对复合树脂固化的影响

目的通过检测比较三种具有较高光密度的光固化灯固化树脂试片的表面硬度值,以评价不同的照射距离对树脂固化程度的影响。方法采用3盏光固化灯聚合90个圆柱形光固化复合树脂试片,固化时间均为40s,聚合时固化灯头与试片表面的距离分别为0mm,3mm,6mm,9mm,12mm,15mm。将固化试片浸泡在蒸馏水中,避光37°C保存24h,测量试片表面和底面的努氏硬度(KHN)。对数据进行统计学分析,计算试片底面与表面最大硬度的百分率,检测试片表面在不同的照射距离所获得的光密度值,取对数后与相应的距离进行直线相关分析。结果光密度的对数值与固化距离呈明显负相关。光固化灯与固化距离对试片的硬度有显著影响。Mini LED AutoFocus固化的硬度值比LEDemetronⅠ和Optilux 401更高,LEDemetronⅠ和Optilux 401的硬度比较没有显著意义。随着固化距离的增加样品的努氏硬度显著下降。大多数实验组都能达到有效的硬度百分率。结论光固化灯灯头与树脂表面距离的微小改变会导致光密度发生显著变化。只有采用具有较高光密度的光敏灯才能满足临床较长照射距离的复合树脂充分固化。

Curing performance of three different curing lights at different distances for a resin composite

Objective To evaluate the performance of three curing lights with high power density at different distances in terms of the surface microhardness of a resin composite.Methods Three types of lights were used to cure 90 cylindrical light-cured resin composite specimens for curing 40 seconds.The distances between curing tip and the surface of specimens were 0mm,3mm,6mm,9mm,12mm,15mm respectively.After photocuring,the specimens were stored in the distilled water in a light proof container at 37°C for 24 hours.The top and bottom of the specimen＇s KHNs were determined.Data were analyzed by statistics software,the valid hardness percent values were messured.The power densities on the surface of the specimen at different curing distances were determined,then the linear regression analysis was performed using logarithm of the power density and the distance from the light curing tips to the radiometer sensor.Results There was a linear relationship between the logarithm of the power density and the curing distance.Curing light and the curing distance influence the hardness significantly.The specimens＇ KHNs cured with the Mini LED AutoFocus light were higher than those photoactivated with the LEDemetron I light and Optilux 401 light.There was no statistically significant difference in KHNs between the LEDemetron I group and the Optilux 401 group.Along with the distance increased,the KHNs were decreased significantly.Most of the experimental groups could obtain the valid hardness percent values.Conclusions The tiny changes of the distances between curing light and the surface of resin would influence the power density significantly.So only using the curing light with higher power density can provide sufficient curing of the composite at a clinically long distance.