Institute of Biomedical Engineering, University of Toronto, Ontario, Canada.
Faculty of Dentistry, University of Toronto, Canada.
Dent Mater. 2024 Oct;40(10):1624-1634. doi: 10.1016/j.dental.2024.07.006. Epub 2024 Jul 31.
The biodegradation of methacrylate (MA)-based dental restoratives has been suggested to contribute to a loss of adhesion and subsequent detachment, or secondary caries, both major causes of restoration failure. Previous studies have demonstrated that intermolecular interactions between resin monomers may affect the hydrolytic-susceptibility of composites. Altering the intermolecular interactions by shielding or masking the hydrolytically-susceptible ester groups found in MA monomers could be an effective strategy to mitigate the biodegradation of resin composites. The objective of this work was to assess whether shielding/masking MAs using fluorinated groups could improve the biostability of experimental composites.
Eight fluorinated monomers (FM) were synthesized, characterized (H NMR), and formulated into experimental resin composites (FC, 65 wt%, microfill). FCs were assessed for interactions with water (water contact angle, water sorption, gel fraction), mechanical properties (both compressive and flexural strength and modulus), cytocompatibility, resistance to biodegradation using simulated human salivary esterase (SHSE) and compared to a control composite (CC) without FM.
Integration of FMs was found to generally decrease both the physical and mechanical properties under all incubation conditions when compared to the CC. Additionally, all FCs had a negative influence on composite biodegradation following immersion in SHSE when compared to the CC.
Shielding/masking MA-esters inherently inserts molecular spaces between the polymer chains within the resin network, and shielding is likely not possible while also maintaining the necessary cohesive forces that regulate the physical and mechanical properties of resin composites. Novel dental resin development should seek to remove/replace vulnerable ester-containing MAs rather that adopting a shielding/masking approach.
已提出甲基丙烯酸酯（MA）基牙科修复体的生物降解有助于丧失附着力和随后的脱落，或继发龋，这是修复体失败的两个主要原因。先前的研究表明，树脂单体之间的分子间相互作用可能会影响复合材料的水解敏感性。通过屏蔽或掩蔽 MA 单体中发现的水解敏感酯基来改变分子间相互作用，可能是减轻树脂复合材料生物降解的有效策略。本工作的目的是评估使用氟化基团屏蔽/掩蔽 MA 是否可以提高实验性复合材料的生物稳定性。
合成了八种氟化单体（FM），并对其进行了表征（H NMR），并将其配制成实验性树脂复合材料（FC，65wt%，微填充）。评估了 FC 与水的相互作用（水接触角、吸水率、凝胶分数）、机械性能（抗压和弯曲强度和模量）、细胞相容性、用模拟人唾液酯酶（SHSE）评估的抗生物降解性，并与不含 FM 的对照复合材料（CC）进行了比较。
与 CC 相比，FM 的整合通常会降低所有孵育条件下的物理和机械性能。此外，与 CC 相比，所有 FC 在浸入 SHSE 后对复合生物降解都有负面影响。
屏蔽/掩蔽 MA-酯固有地在树脂网络中的聚合物链之间插入分子空间，并且在保持调节树脂复合材料物理和机械性能所需的内聚强度的同时，屏蔽可能是不可能的。新型牙科树脂的开发应寻求去除/替换易受攻击的含酯 MA，而不是采用屏蔽/掩蔽方法。
