Bennett Adrian W, Watts David C
Biomaterials Science Unit, Turner Dental School, University of Manchester, Higher Cambridge Street, Manchester M15 6FH, UK.
Dent Mater. 2004 Jan;20(1):72-9. doi: 10.1016/s0109-5641(03)00070-8.
To assess the performance of two blue light-emitting-diode (LED) curing units, in terms of their spectral output and irradiance and the depth of cure (dcure) produced in standard hybrid and modified composites, compared with a conventional quartz tungsten halogen (QTH) light curing unit.
The following light curing units (LCUs) were studied: Elipar-Freelight-1 LED (LED-1) 3 M-ESPE, Ultralume-2 LED (LED-2) Optident, and the Optilux-500 QTH (QTH-1) Sybron-Kerr. For each LCU, using a UV-visible spectrophotometer, the output spectrum was measured and the irradiance of emitted light as a function of source-detector distance. Three composites were studied of similar formulation but differing in their initiator concentrations and/or opacity. These were: Tetric Ceram (A3), Tetric Ceram HB containing an additional photoinitiator responding to approximately 435 nm (A3) and Tetric Ceram Bleach (L). dcure was measured using a calibrated digital needle-penetrometer, as a function of source-specimen distance and for irradiance periods of 10, 20 and 40 s.
Each unit delivered a single peak in the blue region of the visible spectrum. The wavelength maxima for LED-1, LED-2 and QTH-1 were 486.4, 458.2 and 495.2 nm, respectively. Cure-depth (dcure) values varied significantly (p<0.001) with irradiance times and source-specimen distance for both LED and QTH sources. The percentage reduction in dcure values resulting from LED versus QTH irradiance increased with source-specimen distance.
The LED-LCUs had an energy-efficient spectral output for conventional composite curing but had a lower irradiance compared with the QTH-LCU, leading to reduced performance in depths of cure. Design improvements to provide greater irradiance from the LED-1 and to a lesser extent LED-2, should result in increased performance.
评估两款蓝光发光二极管（LED）固化灯的性能，包括其光谱输出、辐照度以及在标准混合和改性复合材料中产生的固化深度（dcure），并与传统的石英钨卤素（QTH）光固化灯进行比较。
研究了以下光固化灯（LCU）：3M-ESPE的Elipar-Freelight-1 LED（LED-1）、Optident的Ultralume-2 LED（LED-2）以及Sybron-Kerr的Optilux-500 QTH（QTH-1）。对于每个LCU，使用紫外可见分光光度计测量输出光谱，并测量发射光的辐照度与光源-探测器距离的函数关系。研究了三种配方相似但引发剂浓度和/或不透明度不同的复合材料。它们分别是：Tetric Ceram（A3）、含有额外对约435nm波长有响应的光引发剂的Tetric Ceram HB（A3）和Tetric Ceram Bleach（L）。使用校准的数字针入度计测量dcure，作为光源-样品距离的函数以及10、20和40秒的辐照时间。
每个灯在可见光谱的蓝色区域都有一个单峰。LED-1、LED-2和QTH-1的最大波长分别为486.4、458.2和495.2nm。对于LED和QTH光源，固化深度（dcure）值随辐照时间和光源-样品距离的变化均有显著差异（p<0.001）。与QTH辐照相比，LED辐照导致的dcure值降低百分比随光源-样品距离增加。
LED-LCU在传统复合材料固化方面具有节能的光谱输出，但与QTH-LCU相比辐照度较低，导致固化深度性能降低。对LED-1进行设计改进以提供更大辐照度，对LED-2进行较小程度的改进，应能提高性能。
