Yoshikawa T, Burrow M F, Tagami J
Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, Japan.
J Adhes Dent. 2001 Summer;3(2):177-83.
The effect of the slow-start curing method on the marginal sealing and cavity wall adaptation on resin composite restorations with different C-factors was evaluated.
Cylindrical cavities, 1 mm deep and 3 mm in diameter (C-factor=2.3) or 2 mm in diameter (C-factor=3) were prepared on flat superficial bovine dentin surfaces. The teeth were restored with Clearfil Photo Bond, Clearfil Liner Bond 2 or Super-Bond D Liner adhesive systems followed by Photo Clearfil Bright composite. The resins were cured with a conventional method using 600 mW/cm2 (tip-to-resin distance 0 mm) for 60 s, or the slow-start curing method of 270 mW/cm2 (tip-to-resin distance 10 mm) for 10 s, followed by a 5-s interval, then 50 s at 600 mW/cm2. After thermocycling, a dye penetration test was carried out. The dye penetration length was calculated as a percentage of the total cavity wall length.
Cavity-wall gap formation increased when the C-factor increased from 2.3 to 3, except in one material, Super-Bond D Liner, which showed good marginal sealing and resin composite adaptation to the cavity wall regardless of light curing method and C-factor.
It is necessary to take care when a cavity with a high C-factor is to be restored with resin composite. The combination of a flexible adhesive and the slow-start curing method would seem to be effective in reducing polymerization contraction stress for large C-factor cavities.
评估慢速启动固化方法对不同C因子的树脂复合材料修复体边缘封闭性和洞壁适应性的影响。
在平坦的牛牙本质表面制备深度为1mm、直径为3mm（C因子=2.3）或直径为2mm（C因子=3）的圆柱形洞。使用Clearfil Photo Bond、Clearfil Liner Bond 2或Super-Bond D Liner粘结系统，随后用光固化Clearfil Bright复合材料修复牙齿。树脂采用传统方法固化，即使用600 mW/cm2（尖端至树脂距离0mm）照射60s，或采用慢速启动固化方法，即270 mW/cm2（尖端至树脂距离10mm）照射10s，间隔5s，然后600 mW/cm2照射50s。热循环后，进行染料渗透试验。染料渗透长度以占洞壁总长度的百分比计算。
当C因子从2.3增加到3时，洞壁间隙形成增加，但有一种材料Super-Bond D Liner除外，无论光固化方法和C因子如何，该材料均显示出良好的边缘封闭性和树脂复合材料与洞壁的适应性。
用树脂复合材料修复高C因子的洞时需要谨慎。对于大C因子的洞，柔性粘结剂与慢速启动固化方法相结合似乎能有效降低聚合收缩应力。
