de Castro Eduardo Fernandes, Fronza Bruna Marin, Soto-Montero Jorge, Giannini Marcelo, Dos-Santos-Dias Carlos Tadeu, Price Richard Bengt
Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, Brazil.
Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, São Paulo, Brazil.
J Esthet Restor Dent. 2023 Mar;35(2):368-380. doi: 10.1111/jerd.12946. Epub 2022 Jul 27.
Evaluate the effect of thickness of high-translucency (HT) CAD/CAM materials on irradiance and beam profile from a blue light-emitting diode light-curing unit (LCU) and on the degree of conversion (DC) and maximum polymerization rate (Rp ) of a light-cured resin cement (LCC).
The direct output from the LCU, the light transmission and irradiance ratio (IR) through one conventional composite and nine HT CAD/CAM materials (0.5, 1.0, 1.5, or 2.0-mm thick; n = 5) were measured with a integrating sphere coupled to a spectrometer. The light beam was assessed with a beam profiler camera. The DC at 600 s and the Rp of one LCC was determined using a Fourier transform infrared spectrometer (n = 5). Data were analyzed by ANOVA followed by Tukey's tests, and Dunnett's test was also used for irradiance data (α = 0.05).
A significant decrease in irradiance through all materials occurred as thickness increased. Thin CAD/CAM materials improved light homogeneity, which decreased with the increase in thickness. The DC of the LCC directly exposed to light was the same as when exposed to 45%, 25%, 15%, or 5% IRs. Rp decreased with the decrease in IR.
Although the HT CAD/CAM materials reduced the irradiance from the LCU, minor effects were observed in the LCC's DC.
Despite the light attenuation of blue light through different CAD/CAM materials that were up to 2-mm thick, the degree of conversion of one brand of light-cured resin cement was clinically acceptable when the LCU was used for 30 s.
评估高透明度（HT）CAD/CAM材料的厚度对蓝光发光二极管光固化机（LCU）的辐照度和光束轮廓以及光固化树脂水门汀（LCC）的转化率（DC）和最大聚合速率（Rp）的影响。
使用与光谱仪耦合的积分球测量LCU的直接输出、透过一种传统复合材料和九种HT CAD/CAM材料（厚度为0.5、1.0、1.5或2.0毫米；n = 5）的光传输和辐照率（IR）。用光束轮廓仪相机评估光束。使用傅里叶变换红外光谱仪测定一种LCC在600秒时的DC和Rp（n = 5）。数据采用方差分析，随后进行Tukey检验，辐照度数据也采用Dunnett检验（α = 0.05）。
随着厚度增加，透过所有材料的辐照度显著降低。薄的CAD/CAM材料改善了光均匀性，随着厚度增加光均匀性降低。直接暴露于光下的LCC的DC与暴露于45%、25%、15%或5% IRs时相同。Rp随着IR的降低而降低。
尽管HT CAD/CAM材料降低了LCU的辐照度，但在LCC的DC方面观察到的影响较小。
尽管蓝光透过厚度达2毫米的不同CAD/CAM材料时会发生光衰减，但当使用LCU照射30秒时，一个品牌的光固化树脂水门汀的转化率在临床上是可接受的。
