Yantcheva Sevda Mihailova
Medical University-Sofia, Faculty of Dental Medicine, Department of Conservative Dentistry, 1, G. Sofiiski Bvd., 1431 Sofia, Bulgaria.
Polymers (Basel). 2021 May 20;13(10):1660. doi: 10.3390/polym13101660.
The development of composite materials is subject to the desire to overcome polymerization shrinkage and generated polymerization stress. An indicator characterizing the properties of restorative materials, with specific importance for preventing secondary caries, is the integrity and durability of marginal sealing. It is a reflection of the effects of polymerization shrinkage and generated stress. The present study aimed to evaluate and correlate marginal integrity and micropermeability in second-class cavities restored with three different types of composites, representing different strategies to reduce polymerization shrinkage and stress: nanocomposite, silorane, and bulk-fill composite after a ten-month ageing period. Thirty standardized class ΙΙ cavities were prepared on extracted human molars. Gingival margins were 1 mm apical to the cementoenamel junction. Cavities were randomly divided into three groups, based on the composites used: FiltekUltimate-nanocomposite; Filtek Silorane LS-silorane; SonicFill-bulk-fill composite. All specimens were subjected to thermal cycles after that, dipped in saline for 10-mounds. After ageing, samples were immersed in a 2% methylene blue. Thus prepared, they were covered directly with gold and analyzed on SEM for assessment of marginal seal. When the SEM analysis was completed, the teeth were included into epoxy blocks and cut longitudinally on three slices for each cavity. An assessment of microleakage on stereomicroscope followed. Results were statistically analyzed. For marginal seal evaluation: F.Ultimate and F.Silorane differ statistically with more excellent results than SonicFill for marginal adaptation to the gingival margin, located entirely in the dentin. For microleakage evaluation: F.Ultimate and F.Silorane differ statistically with less microleakage than SonicFill. Based on the results obtained: a strong correlation is found between excellent results for marginal adaptation to the marginal gingival ridge and micropermeability at the direction to the axial wall. We observe a more significant influence of time at the gingival margin of the cavities. There is a significant increase in the presence of marginal fissures ( = 0.001). A significant impact of time ( < 0.000) and of the material ( < 0.000) was found in the analysis of the microleakage.
复合材料的发展受到克服聚合收缩和聚合应力的需求的推动。表征修复材料性能的一个指标，对预防继发龋具有特殊重要性，是边缘封闭的完整性和耐久性。它反映了聚合收缩和产生的应力的影响。本研究旨在评估和关联用三种不同类型的复合材料修复的二类洞在十个月老化期后的边缘完整性和微渗漏情况，这三种复合材料代表了减少聚合收缩和应力的不同策略：纳米复合材料、硅氧烷和大块充填复合材料。在拔除的人类磨牙上制备了30个标准化的二类洞。牙龈边缘位于牙骨质釉质界根尖1毫米处。根据所用的复合材料，将洞随机分为三组：FiltekUltimate - 纳米复合材料；Filtek Silorane LS - 硅氧烷；SonicFill - 大块充填复合材料。之后所有标本都进行了热循环，在盐水中浸泡10个月。老化后，将样本浸入2%的亚甲蓝中。如此制备后，直接用金覆盖并在扫描电子显微镜下分析以评估边缘封闭情况。当扫描电子显微镜分析完成后，将牙齿嵌入环氧树脂块中，每个洞纵向切成三片。随后在立体显微镜下评估微渗漏情况。对结果进行了统计分析。对于边缘封闭评估：FiltekUltimate和Filtek Silorane在统计学上存在差异，在边缘适应牙龈边缘方面的结果比SonicFill更优，牙龈边缘完全位于牙本质内。对于微渗漏评估：FiltekUltimate和Filtek Silorane在统计学上存在差异，微渗漏比SonicFill少。基于获得的结果：在边缘适应边缘牙龈嵴的优异结果与向轴向壁方向的微渗透性之间发现了很强的相关性。我们观察到时间对洞的牙龈边缘有更显著的影响。边缘裂隙的出现有显著增加（P = 0.001）。在微渗漏分析中发现时间（P < 0.000）和材料（P < 0.000）有显著影响。
