Yearn J A
Int Dent J. 1985 Sep;35(3):218-25.
Since visible light activated composites first appeared in 1978 they have become internationally popular for the aesthetic restoration of anterior teeth. With an ever increasing number of composite formulations and curing lights available and as yet no widely recognized standard for measuring depth of cure, it is difficult to interpret claims being made by manufacturers. A laboratory technique using incremental measurement of surface hardness has been shown to provide a convenient means of assessing cure throughout the depth of a composite sample, which relates to the clinical situation. Using this method it is possible to demonstrate that physical and chemical formulation factors; the nature of the light source; and the control exercised by the practitioner, are all important in determining the quality of cure achieved and hence likely long term performance of the restoration. Light cured composites are now being more widely used in the restoration of occlusal cavities in posterior teeth, where the technique offers advantages of control, handleability and a lack of porosity unattainable in a chemically cured system. In large Class II cavities depths can exceed 7 mm, and in an application where performance is critical it is essential that a satisfactory level of cure is achieved. To obtain this, even with exposure times significantly longer than those currently being recommended, it is advisable to employ a layering technique for any cavity greater than 3 or 4 mm in depth.
自1978年可见光激活复合材料首次出现以来，它们在国际上已广泛用于前牙的美学修复。随着复合材料配方和固化灯的数量不断增加，且目前尚无广泛认可的固化深度测量标准，因此很难解读制造商所宣称的内容。一种使用表面硬度增量测量的实验室技术已被证明是评估复合材料样品整个深度固化情况的便捷方法，这与临床情况相关。使用这种方法可以证明，物理和化学配方因素、光源的性质以及从业者的操作控制，在决定所实现的固化质量以及修复体可能的长期性能方面都很重要。光固化复合材料现在越来越广泛地用于后牙咬合面洞的修复，该技术具有控制、易操作性以及化学固化系统无法实现的无孔隙等优点。在大型Ⅱ类洞中，深度可能超过7毫米，在性能至关重要的应用中，实现令人满意的固化水平至关重要。为了达到这一点，即使曝光时间明显长于目前推荐的时间，对于深度大于3或4毫米的任何洞，建议采用分层技术。
