Student Research Committee, Babol University of Medical Sciences, Babol, Iran.
Dental Materials Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran.
Eur Arch Paediatr Dent. 2023 Aug;24(4):473-479. doi: 10.1007/s40368-023-00812-3. Epub 2023 Jun 21.
To investigate the effect of pre-cured and co-cured flowable composite liner on fracture strength and microleakage of primary anterior teeth with extended composite resin restorations.
In the current in vitro experimental study, the crowns of 54 extracted primary canine teeth were cut 1 mm above the CEJ, and a pulpectomy procedure was performed. The samples were randomly divided into three groups to restore the coronal part up to 4 mm above the CEJ. In group 1, the samples were built up with Filtek Z250 packable composite resin. In group 2 (pre-cure), first, 1 mm of Filtek Z350 XT flowable liner was applied to the sample, and after curing, the restoration process continued using packable composite resin. In group 3 (co-cure), the flowable composite liner was cured while the first layer of packable composite resin was applied; then, the same restorative procedure similar to the other groups was followed. The samples' cross-sectional area in the fracture strength test was calculated by AutoCAD software. Subsequently, the samples were subjected to a force in a universal testing machine. The samples related to the microleakage experiment were cut vertically, and then, the dye penetration percentage (10% methylene blue) was measured under a stereomicroscope. ANOVA was used to analyze the data.
Mean fracture strength in group 2 was significantly higher than in group 1 (P = 0.016). The microleakage mean in group 3 was significantly lower than in groups 1 (P = 0.000) and 2 (P = 0.026).
The flowable composite liner and its relevant separate curing increased the fracture strength of composite resin restorations. However, less microleakage was reported in the group where the liner was applied as a co-cure.
研究预固化和共固化流动复合衬垫对前牙延长复合树脂修复体的断裂强度和微渗漏的影响。
在本体外实验研究中，将 54 颗拔除的恒前磨牙的牙冠切至龈缘上方 1mm，行牙髓切除术。将样本随机分为三组，修复体冠部高度至龈缘上方 4mm。在第 1 组，使用 Filtek Z250 可压实复合树脂进行修复。在第 2 组（预固化）中，首先在样本上应用 1mm 的 Filtek Z350 XT 流动衬垫，固化后继续使用可压实复合树脂进行修复。在第 3 组（共固化）中，在应用第一层可压实复合树脂的同时固化流动复合衬垫，然后再进行类似其他组的修复。通过 AutoCAD 软件计算断裂强度试验中样本的横截面积。随后，将样本置于万能试验机上施加力。与微渗漏实验相关的样本垂直切割，然后在立体显微镜下测量染料渗透百分比（10%亚甲蓝）。采用 ANOVA 进行数据分析。
第 2 组的平均断裂强度明显高于第 1 组（P=0.016）。第 3 组的微渗漏平均值明显低于第 1 组（P=0.000）和第 2 组（P=0.026）。
流动复合衬垫及其相关的单独固化可提高复合树脂修复体的断裂强度。然而，在共固化时应用衬垫的组报告的微渗漏较少。
