The effect of light intensity on double bond conversion and flexural strength of a model, unfilled dental resin
The effect of light intensity on double bond conversion and flexural strength of a model, unfilled dental resin
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DOI：
10.1016/s0109-5641(02)00090-8
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发表时间：
2003-09-01
期刊：
影响因子：
5
通讯作者：
Bowman, CN
中科院分区：
文献类型：
--
作者：
Lovell, LG;Newman, SM;Bowman, CN
Objective.使用强度截然不同（200和1800 mw/cm（2））但光谱输出相似的两种可见光源（钨石英卤素和氙弧等离子体）来检查光强度对模型牙科树脂配方（75/25重量% bis-GMA/TEGDMA）的转化率和弯曲强度的影响。方法。使用完全相同的聚合物样品将双键转化率（用近红外光谱法测量）与弯曲强度相关联，无论是在光照后还是储存后。一般而言，用高光强源照射的聚合物表现出更高的双键转化率。然而，增加光强度也增加了聚合期间达到的最高温度。因此，较大的双键转化率是由光和热效应的组合引起的。无论光强度如何，在分析的转化率范围（50-80%）内，转化率和最终弯曲强度（固化后4天测量）之间存在单一线性关系。然而，在检测后立即检测的几个样品中观察到线性偏差。显著性。这些发现表明，只要最终转化率相似，光强度不会影响牙科树脂的最终弯曲强度。(C)2003年牙科材料学院。由爱思唯尔科技有限公司出版。保留所有权利。
Objective. Two visible light sources (tungsten-quartz-halogen and xenon-arc plasma) with vastly different intensities (200 and 1800 mw/cm(2)) but similar spectral outputs, were used to examine the effects of light intensity on conversion and flexural strength of a model dental resin formulation (75/25 wt% bis-GMA/TEGDMA).Methods. The exact same polymer samples were used to correlate double bond conversion (measured with near-IR spectroscopy) to flexural strength, both immediately after light exposure and after storage.Results. In general, polymers which were irradiated with the high light intensity source exhibited greater double bond conversion. However, increasing the light intensity also increased the maximum temperature reached during polymerization. Therefore, the greater double bond conversion was caused by a combination of both photo and thermal effects. Regardless of the light intensity, a single linear relationship existed between conversion and final flexural strength (measured 4 days after cure) over the conversion range analyzed (50-80%). However, deviations from linearity were noted in several samples that were tested immediately after exposure.Significance. These findings illustrate that light intensity does not affect the final flexural strength of a dental resin as long as the final conversions are similar. (C) 2003 Academy of Dental Materials. Published by Elsevier Science Ltd. All rights reserved.