Study on unpolymerized area in the surface layer of light activated composite resins

本研究的目的是确定表面未聚合层的实际情况，并制定一些临床对策。因此，首先对表面未聚合层进行了研究。得到了以下结果：树脂初凝后，随着时间的推移，修复体的固化程度继续增加，但未聚合层持续留在修复体表面，这可能是导致表面降解的原因。许多临床程序；使用基质，延长照射时间，在光单元端使用白尖保护器等先前报道的技术来提高修复表面的固化程度，进行了尝试。不幸的是，表面的固化程度得到了显著改善，但无法阻止层的出现。这是最好的方式，去除层通过整理和抛光程序，在更短的时间内。因此，为了确定未聚合层的实际范围，必须通过努氏硬度测量作为参数来检测商业产品表面区域中相对适当的固化面积。因为，未聚合或未充分固化的区域可能出现在表层。沿辐照方向从辐照表面正下方到深度处进行努氏硬度测量，得到硬度随深度的变化曲线。从曲线上的硬度峰值，可以确定必须通过抛光去除的树脂产品的深度。研究结论如下。首先，光活化复合树脂应在腔内过度填充（约0.5 mm）。初始凝固后，必须通过精加工或抛光程序去除多余的材料。因此，可以在修复上暴露具有最佳表面纹理的表面。少

The purpose of this study was to determine the actual situation of the unpolymerized layer in the surface area and make up some clinical counterplan for it. Therefore, Firstly, the study on the unpolymerized layer in the surface was conducted.The following results were obtained. After initial setting of the resin, the degree of cure for the restoration continues to increase with time, but the unpolymerized layer continuously remaines at the surface of restoration, that might be the cause of surface degradation. Many clinical procedures ; using a matrix, prolonged irradiation time, using a white tip protector on the light unit end, and so on , which techniques were previously reported to improve the degree of cure on the surface of the restoration, were attempted. Unfortunately, the degree of cure at the surface area was remarkably improved but the apperance of the layer could not be prevented. It is the best way that the removal of layer by finishing and polishing procedures, at the pr … More esent moment. Therefore, in order to determine the actual range of the unpolymerized layer, the relatively properly cured area in the surface region of the commercial products has to be detected by means of the Knoop hardness measurement as a parameter. Because, the area where is unpolymerized or inadequately cured might be appeared at the surface layer. The Knoop hardness measurements were carried out from the area just below the irradiation surface to the depths along the irradiation direction, to obtain the hardness vs. depth curve. From the peak hardness on the curve, it is possible to determine the depth of resin products which must be removed by polishing.The conclusions are as follows.At first, the light activated composite resin should be overfilled ( approximately 0.5 mm ) in the cavity. After initial setting, the excess material must be removed by finishing or polishing procedure. Consequently, it is possible to expose the surface having the best surface texture on the restoration. Less