Han S H, Park S H
Oper Dent. 2017 Mar/Apr;42(2):203-214. doi: 10.2341/16-023-L. Epub 2016 Nov 28.
This study compared the internal adaptation of bulk-fill composite restorations in class II cavities and explored the relationship between internal adaptation and polymerization shrinkage or stress.
Standardized mesio-occluso-distal cavities were prepared in 40 extracted human third molars and randomly divided into five groups (n=8). After having been applied by total-etch XP bond (Dentsply Caulk, Milford, DE, USA) and light curing, the teeth were restored with the following resin composites: group 1, Filtek Z350 (3M ESPE, St. Paul, MN, USA); group 2, SDR (Dentsply Caulk, Milford, DE, USA) + Z350; group 3, Venus Bulk Fill (Heraeus Kulzer, Dormagen, Germany) + Z350; group 4, Tetric N-Ceram Bulk Fill (Ivoclar Vivadent, Schaan, Liechtenstein); and group 5, SonicFill (Kerr, West Collins, Orange, CA, USA). After thermo-mechanical load cycling, cross-sectional microcomputerized tomography (micro-CT) images were taken. Internal adaptation was measured as imperfect margin percentage (IM%), which was the percentage of defective margin length relative to whole margin length. On the micro-CT images, IM% was measured at five interfaces. Linear polymerization shrinkage (LS) and polymerization shrinkage stress (PS) were measured on each composite with a custom linometer and universal testing machine. To explore the correlation of IM% and LS or PS, the Pearson correlation test was used.
The IM% of the gingival and pulpal cavity floors were inferior to those of the cavity walls. The IM% values of the groups were found to be as follows: group 5 ≤ groups 1 and 4 ≤ group 2 ≤ group 3. The correlation analysis showed that the p value was 0.006 between LS and IM% and 0.003 between PS and IM%, indicating significant correlations (p<0.05).
Flowable bulk-fill composites had a higher IM% and polymerization shrinkage stress than did packable bulk-fill and hybrid composites. In class II composite restoration, the gingival floor of the proximal box and pulpal floor of the cavity had higher IM% than did the buccal and lingual walls of the proximal box. LS and PS, which were measured under compliance-allowed conditions, were significantly related to internal adaptation.
本研究比较了Ⅱ类洞型中大块充填复合树脂修复体的内部适应性，并探讨了内部适应性与聚合收缩或应力之间的关系。
在40颗拔除的人类第三磨牙上制备标准化的近中-咬合-远中洞型，并随机分为五组（n = 8）。在应用全酸蚀XP粘结剂（美国特拉华州米尔福德登士柏卡沃公司）并光固化后，用以下复合树脂修复牙齿：第1组，Filtek Z350（美国明尼苏达州圣保罗3M ESPE公司）；第2组，SDR（美国特拉华州米尔福德登士柏卡沃公司）+ Z350；第3组，Venus Bulk Fill（德国多马根贺利氏古莎公司）+ Z350；第4组，Tetric N-Ceram Bulk Fill（列支敦士登公国沙恩义获嘉伟瓦登特公司）；第5组，SonicFill（美国加利福尼亚州奥兰治柯尔公司）。在进行热机械加载循环后，拍摄横断面微计算机断层扫描（micro-CT）图像。内部适应性以不完美边缘百分比（IM%）来衡量，即缺陷边缘长度相对于整个边缘长度的百分比。在micro-CT图像上，在五个界面处测量IM%。用定制的线性测量仪和万能试验机测量每种复合材料上的线性聚合收缩（LS）和聚合收缩应力（PS）。为了探讨IM%与LS或PS的相关性，使用了Pearson相关性检验。
龈壁和髓壁的IM%低于洞壁的IM%。发现各分组的IM%值如下：第5组≤第1组和第4组≤第2组≤第3组。相关性分析表明，LS与IM%之间的p值为0.006，PS与IM%之间的p值为0.003，表明存在显著相关性（p<0.05）。
可流动大块充填复合树脂比可压实大块充填复合树脂和混合复合树脂具有更高的IM%和聚合收缩应力。在Ⅱ类复合树脂修复中，近中盒的龈壁和髓壁的IM%高于近中盒的颊壁和舌壁。在顺应性允许条件下测量的LS和PS与内部适应性显著相关。
