Department of Operative/Restorative Dentistry, Periodontology and Pedodontics, Ludwig-Maximilians University Munich, Goethestrasse 70, 80336 Munich, Germany.
Dent Mater. 2020 Aug;36(8):e255-e265. doi: 10.1016/j.dental.2020.04.018. Epub 2020 Jun 3.
Measurement of irradiance passing through a dental restoration for properly curing a dual- or light-polymerized luting composite is imprecise due to surface reflection.
To provide a mathematical correction of measured transmitted irradiance for predicting true transmitted light intensity through CAD/CAM restorations.
A total of 432 specimens were fabricated. Seven modern CAD/CAM resin-based composites (RBCs) and one CAD/CAM glass-ceramic (control group) were sectioned and polished into specimens of 0.5-5mm thickness (in 0.5mm steps, n=6). Irradiance of a violet-blue LED light curing unit (LCU) (power modes: Standard, High and Plasma) was measured after passing through each specimen with a spectrometer. Data was compared based on 95% confidence intervals and using univariate ANOVA followed by Tukey HSD (α=0.05).
The measured transmitted irradiance passing through the specimens decreased exponentially. Significantly highest values of transmitted irradiance were measured for 0.5mm thick specimens for all materials (p<0.05). The decadic absorption coefficient for CAD/CAM-RBCs ranged from 0.292mm to 0.387mm while the control group (glass-ceramic) reached a significantly lower value of 0.283mm. The reflection ratio for all materials ranged from 12.6% to 18.5%.
A correction can be implemented to predict the true transmitted irradiance after passing through a dental restoration as function of initial irradiance, specimen thickness and material specific parameters. For a practitioner, this model may be applied depending on the specific treatment conditions, the individual LCU's radiant emittance and restoration thickness for the tested materials.
由于表面反射，通过牙科修复体测量用于适当固化双固化或光固化水门汀的辐照度并不精确。
为了提供一种对测量的透过辐照度的数学修正，以预测通过 CAD/CAM 修复体的真实透过光强度。
共制作了 432 个样本。7 种现代 CAD/CAM 树脂基复合材料（RBC）和 1 种 CAD/CAM 玻璃陶瓷（对照组）被切割并抛光成 0.5-5mm 厚度的样本（以 0.5mm 为步长，n=6）。使用分光光度计测量经过每个样本后的紫蓝色 LED 光固化器（LCU）的辐照度。基于 95%置信区间和单因素方差分析（ANOVA）后进行 Tukey HSD（α=0.05）比较数据。
透过样本的测量透过辐照度呈指数下降。所有材料的 0.5mm 厚样本的透过辐照度值最高（p<0.05）。CAD/CAM-RBC 的十进制吸收系数范围为 0.292mm 至 0.387mm，而对照组（玻璃陶瓷）的吸收系数明显较低，为 0.283mm。所有材料的反射率范围为 12.6%至 18.5%。
可以实施一种修正，以预测经过牙科修复体后的真实透过辐照度，其作为初始辐照度、样本厚度和材料特定参数的函数。对于从业者来说，根据特定的治疗条件、个别 LCU 的辐射发射率和测试材料的修复体厚度，可以应用该模型。
