Development and characterization of a novel bulk-fill elastomeric temporary restorative composite

Abstract Objectives: This study investigated the physical and mechanical properties, antibacterial effect and biocompatibility of novel elastomeric temporary resin-based filling materials (TFMs) containing zinc methacrylate (ZM). Material and Methods: Experimental TFMs were prepared by mixing the zinc methacrylate with monomer, co-monomer, photoinitiator and fillers. A ZM concentration of 0 (control), 0.5% (Z0.5); 1% (Z1), 2% (Z2), or 5% (ZM5) wt% was added to the TFMs. Fermit-N (F) was used for comparison with the experimental material. Microleakage, water sorption/solubility, degree of conversion, depth of cure, ultimate tensile strength, and hardness were determined and compared. A modified direct contact test (DCT) with Enterococcus faecalis and a Streptococcus mutans’ biofilm accumulation assay was carried out to evaluate the antimicrobial effect and cytotoxicity of the assay. Statistical comparisons were performed (α=5%). Results: The results showed that the physical and mechanical properties of the experimental TFMs with ZM are comparable with the properties of the commercial reference and some properties were improved, such as lower microleakage and water sorption, and higher ultimate tensile strength values. TFMs with ZM killed E. faecalis only after 1 h. Biofilm development of S. mutans was not affected by the inclusion of ZM in the experimental TFMs. Conclusions: The present findings suggest that the physical, mechanical and biological properties of the experimental TFMs with ZM are comparable with the properties of the commercial reference. However, some properties were improved, such as lower microleakage and water sorption, and higher ultimate tensile strength values.

摘要 研究目的：本研究旨在探究添加甲基丙烯酸锌（zinc methacrylate, ZM）的新型弹性体临时树脂基充填材料（temporary resin-based filling materials, TFMs）的物理力学性能、抗菌效果与生物相容性。
材料与方法：将甲基丙烯酸锌与单体、共聚单体、光引发剂及填料混合，制备实验用TFMs。实验分组为添加0（对照组）、0.5%、1%、2%及5%质量分数的ZM，分别记为Z0.5、Z1、Z2、ZM5。以Fermit-N（F）作为实验对照材料。对各组材料的微渗漏、吸水率/溶解性、聚合转化率、固化深度、极限拉伸强度及硬度进行检测与对比。采用改良直接接触试验（direct contact test, DCT）检测粪肠球菌（Enterococcus faecalis）的抗菌效果，并通过变形链球菌（Streptococcus mutans）生物膜蓄积试验评估细胞毒性，所有统计检验均采用α=5%的显著性水平。
结果：结果显示，添加ZM的实验TFMs的物理力学性能与市售对照材料相当，部分性能更优，例如更低的微渗漏与吸水率，以及更高的极限拉伸强度。添加ZM的TFMs仅在1小时后即可杀灭粪肠球菌。实验TFMs中添加ZM对变形链球菌的生物膜形成无显著影响。
结论：本研究结果表明，添加ZM的实验TFMs的物理、力学及生物学性能与市售对照材料相当，部分性能得到改善，包括更低的微渗漏与吸水率，以及更高的极限拉伸强度。