Yamamoto Akira, Miyazaki Masashi, Rikuta Akitomo, Kurokawa Hiroyasu, Takamizawa Toshiki
Department of Operative Dentistry, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan.
Dent Mater. 2007 Jul;23(7):792-8. doi: 10.1016/j.dental.2006.06.018. Epub 2006 Aug 7.
The purpose of this study was to compare two methods for assessing the polymerization characteristics of flowable resin composites.
Two different flowable resin composites and a hybrid resin composite control were investigated. In order to measure the volumetric shrinkage (DeltaV), each material was placed into a mould and extruded into a water-filled dilatometer. The specimens were then light irradiated for 30s using a curing unit with the power density adjusted to either 100 or 600mW/cm(2). For the speckle contrast measurement, each resin composite was condensed into a glass tube and irradiated. The laser-speckle field was recorded in a digital frame. The calculated values were obtained for each pair of adjacent patterns and the changes in speckle contrast as a function of time were obtained.
The average DeltaV values of the resins after 180s ranged from approximately 3.3 to 4.4% for the flowable composites and from approximately 1.8 to 2.3% for the hybrid composite control. The overall magnitude of the speckle contrasts decreased soon after the initial light exposure commenced and gradually increased thereafter. The speckle contrast measurements revealed changes in the pastes due to the polymerization of the flowable resins that were greater than those obtained with the water-filled dilatometer.
These data suggest that the polymerization characteristics of flowable resins can be measured successfully using two different methods. Moreover, our findings are of clinical relevance, as the data obtained under laboratory conditions might give an indication of the suitability of flowable resin composites for specific clinical applications.
本研究的目的是比较两种评估可流动树脂复合材料聚合特性的方法。
研究了两种不同的可流动树脂复合材料和一种混合树脂复合材料对照。为了测量体积收缩率（ΔV），将每种材料放入模具中并挤入充满水的膨胀仪中。然后使用功率密度调整为100或600mW/cm²的固化装置对样本进行30秒的光照射。对于散斑对比度测量，将每种树脂复合材料浓缩到玻璃管中并进行照射。在数字帧中记录激光散斑场。获得每对相邻图案的计算值，并获得散斑对比度随时间变化的情况。
180秒后，可流动复合材料的树脂平均ΔV值约为3.3%至4.4%，混合复合材料对照的平均ΔV值约为1.8%至2.3%。初始光照射开始后不久，散斑对比度的总体幅度下降，此后逐渐增加。散斑对比度测量显示，可流动树脂聚合导致糊剂的变化大于充满水的膨胀仪所测得的变化。
这些数据表明，可以使用两种不同的方法成功测量可流动树脂的聚合特性。此外，我们的发现具有临床相关性，因为在实验室条件下获得的数据可能表明可流动树脂复合材料对特定临床应用的适用性。
