Christensen R P, Palmer T M, Ploeger B J, Yost M P
Compend Contin Educ Dent Suppl. 1999(25):S42-54; quiz S74.
Negative effects of rapid, high-intensity resin curing have been predicted for both argon lasers and plasma-arc curing lights. To address these questions, six different resin restorative materials were cured with 14 different resin curing lights representing differences in intensities ranging from 400 mW/cm2 to 1,900 mW/cm2; delivery modes using constant, ramped, and stepped methods; cure times ranging from 1 second to 40 seconds; and spot sizes of 6.7 mm to 10.9 mm. Two lasers, five plasma-arc lights, and seven halogen lights were used. Shrinkage, modulus, heat generation, strain, and physical changes on the teeth and resins during strain testing were documented. Results showed effects associated with lights were not statistically significant, but resin formulation was highly significant. Microfill resins had the least shrinkage and the lowest modulus. An autocure resin had shrinkage and modulus as high as or higher than the light-cured hybrid resins. Lasers and plasma-arc lights produced the highest heat increases on the surface (up to 21 degrees C) and within the resin restorations (up to 14 degrees C), and the halogen lights produced the most heat within the pulp chamber (up to 2 degrees C). Strain within the tooth was least with Heliomolar and greatest with Z100 Restorative and BISFIL II autocure resin. Clinical effects of strain relief were evident as white lines at the tooth-resin interface and cracks in enamel adjacent to the margins. This work implicates resin formulation, rather than light type or curing mode, as the important factor in polymerization problems. Lower light intensity and use of ramped and stepped curing modes did not provide significant lowering of shrinkage, modulus, or strain, and did not prevent enamel cracking adjacent to margins and formation of "white line" defects at the margins. Until materials with lower shrinkage and modulus are available, use of low-viscosity surface sealants as a final step in resin placement is suggested to seal defects.
对于氩离子激光和等离子弧固化灯，快速、高强度树脂固化的负面影响已被预测。为了解决这些问题，使用14种不同的树脂固化灯对六种不同的树脂修复材料进行固化，这些固化灯在强度上有所不同，范围从400 mW/cm²到1,900 mW/cm²；采用恒定、渐变和阶梯式方法的输送模式；固化时间从1秒到40秒不等；光斑尺寸为6.7毫米至10.9毫米。使用了两台激光器、五台等离子弧灯和七台卤素灯。记录了应变测试过程中牙齿和树脂的收缩、模量、产热、应变以及物理变化。结果表明，与灯相关的影响在统计学上不显著，但树脂配方具有高度显著性。微填料树脂收缩最小且模量最低。一种自凝树脂的收缩和模量与光固化复合树脂一样高或更高。激光和等离子弧灯在树脂修复体表面（高达21摄氏度）和内部（高达14摄氏度）产生的热量增加最多，而卤素灯在牙髓腔内产生的热量最多（高达2摄氏度）。使用Heliomolar时牙齿内的应变最小，而使用Z100修复材料和BISFIL II自凝树脂时应变最大。应变缓解的临床效果表现为牙齿 - 树脂界面处的白线以及边缘附近牙釉质中的裂纹。这项研究表明，在聚合问题中，重要因素是树脂配方，而非光的类型或固化模式。较低的光强度以及使用渐变和阶梯式固化模式并不能显著降低收缩、模量或应变，也无法防止边缘附近的牙釉质开裂以及边缘处“白线”缺陷的形成。在有收缩和模量更低的材料可用之前，建议在树脂填充的最后一步使用低粘度表面密封剂来封闭缺陷。
