Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Gunduliceva 5, Zagreb, Croatia.
Private Dental Office, Zagreb, Croatia.
Clin Oral Investig. 2019 Dec;23(12):4399-4409. doi: 10.1007/s00784-019-02896-y. Epub 2019 Apr 10.
To evaluate light transmittance as a function of wavelength for eight composite materials and compare the transmittance for blue light produced from two curing units with different emission spectra.
Light transmittance through 2- and 4-mm-thick composite specimens was recorded in real time during 30 s of curing using a broad-spectrum (peaks at 405 and 450 nm) and a narrow-spectrum (peak at 441 nm) LED-curing unit. The spectral resolution of 0.25 nm and temporal resolution of 0.05 s resulted in a large amount of light transmittance data, which was averaged over particular spectral ranges, for the whole measurement period. Statistical analysis was performed using Welch ANOVA with Games-Howell post hoc test, t test, and Pearson correlation analysis. The level of significance was 0.05 and n = 5 specimens per experimental group were prepared.
Light transmittance varied as a function of wavelength and time, revealing significantly different patterns among the tested materials. Light transmittance for different parts of curing unit spectra increased in the following order of emission peaks (nm): 405 < 441 < 450. Of particular interest was the difference in transmittance between 441 and 450 nm, as these peaks are relevant for the photoactivation of camphorquinone-containing composites. A high variability in light transmittance among materials was identified, ranging from statistically similar values for both peaks up to a fourfold higher transmittance for the peak at 450 nm.
Each material showed a unique pattern of wavelength-dependent light transmittance, leading to highly material-dependent differences in blue light transmittance between two curing units.
Minor differences in blue light emission of contemporary narrow-peak curing units may have a significant effect on the amount of light which reaches the composite layer bottom.
评估八种复合材料的透光率随波长的变化，并比较两种具有不同发射光谱的光固化单元产生的蓝光透光率。
使用宽光谱（峰值分别为 405nm 和 450nm）和窄光谱（峰值为 441nm）LED 光固化单元，在 30s 的固化过程中实时记录 2mm 和 4mm 厚的复合材料样本的透光率。0.25nm 的光谱分辨率和 0.05s 的时间分辨率产生了大量的透光率数据，这些数据在整个测量期间在特定的光谱范围内进行平均。使用 Welch ANOVA 与 Games-Howell 事后检验、t 检验和 Pearson 相关分析进行统计分析。显著性水平为 0.05，每个实验组制备 5 个样本。
透光率随波长和时间而变化，揭示了测试材料之间明显不同的模式。不同部分的固化单元光谱的透光率增加顺序为发射峰（nm）：405<441<450。特别值得注意的是 441nm 和 450nm 之间的透光率差异，因为这些峰与含樟脑醌的复合材料的光激活有关。不同材料之间的透光率存在很大的差异，从两个峰值的统计学相似值到 450nm 峰值的四倍更高透光率不等。
每种材料都表现出独特的波长相关透光率模式，导致两个光固化单元之间的蓝光透光率具有高度依赖于材料的差异。
当代窄峰光固化单元的蓝光发射差异很小，但可能对到达复合材料层底部的光量产生重大影响。
