Obici A C, Sinhoreti M A C, de Goes M F, Consani S, Sobrinho L C
Department of Restorative Dentistry, Dental School of Piracicaba, UNICAMP, SP, Brazil.
Oper Dent. 2002 Mar-Apr;27(2):192-8.
This study measured the gap that resulted from polymerization shrinkage of seven restorative resin composites after curing by three different methods. Contraction behavior, according to the specimen region, was also characterized. The materials used for this study were Alert (Jeneric/Pentron, Wallingford, CT 06492, USA), Surefil (Dentsply Caulk, Milford, DE 19963, USA), P60 (3M Dental Products, St Paul, MN 55144, USA), Z250 (3M), Z100 (3M), Definite (Degussa-Hüls, Hanau, Germany) and Flow-it (Jeneric/Pentron). The composite was placed in a circular brass mold 7 mm in diameter and 2 mm in height. Photo-activation was performed by a) continuous light (500 mW/cm2) for 40 seconds; b) stepped light with low intensity (150 mW/cm2) for 10 seconds and high intensity (500 mW/cm2) for 30 seconds and c) intermittent light (450 mW/cm2) for 60 seconds. The top and bottom surfaces were then polished and after 24 +/- 1 hours, the contraction gap was measured by SEM at variable pressure (LEO 435 VP, Cambridge, England). Results were analyzed by ANOVA and the means compared by Tukey's test (5%). The results demonstrated 1) the continuous light method presented the greatest gap values (15.88 microm), while the other methods demonstrated lower polymerization shrinkage values (stepped light, 13.26 microm; intermittent light, 12.79 microm); 2) restorative composites shrunk more at the bottom surface (15.84 microm) than at the top surface (12.11 microm) and (3) the composites Alert (12.02 microm), Surefil (11.86 microm), Z250 (10.81 microm) and P60 (10.17 microm) presented the least contraction gaps, followed by Z100 (15.84 microm) and Definite (14.06 microm) and finally Flow-it (23.09 microm) low viscosity composite, which had the greatest mean value.
本研究测量了七种修复性树脂复合材料通过三种不同方法固化后因聚合收缩而产生的间隙。还根据试样区域对收缩行为进行了表征。本研究使用的材料有Alert（美国康涅狄格州沃灵福德市Jeneric/Pentron公司，邮编06492）、Surefil（美国特拉华州米尔福德市登士柏卡克公司，邮编19963）、P60（美国明尼苏达州圣保罗市3M牙科产品公司，邮编55144）、Z250（3M公司）、Z100（3M公司）、Definite（德国哈瑙市德固赛-赫尔斯公司）和Flow-it（Jeneric/Pentron公司）。将复合材料置于直径7毫米、高2毫米的圆形黄铜模具中。光固化通过以下方式进行：a）连续光（500 mW/cm²）照射40秒；b）低强度（150 mW/cm²）光照射10秒，高强度（500 mW/cm²）光照射30秒；c）间歇光（450 mW/cm²）照射60秒。然后对顶面和底面进行抛光，在24±1小时后，通过可变压力扫描电子显微镜（英国剑桥市LEO 435 VP型）测量收缩间隙。结果通过方差分析进行分析，均值通过Tukey检验（5%）进行比较。结果表明：1）连续光固化法产生的间隙值最大（15.88微米），而其他方法的聚合收缩值较低（阶梯光固化法为13.26微米；间歇光固化法为12.79微米）；2）修复性复合材料底面的收缩（15.84微米）比顶面（12.11微米）更明显；3）Alert（12.02微米）、Surefil（11.86微米）、Z250（10.81微米）和P60（10.17微米）等复合材料的收缩间隙最小，其次是Z100（15.84微米）和Definite（14.06微米），最后是Flow-it（23.09微米）低粘度复合材料，其平均值最大。
