Department of Surgical and Developmental Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA.
TDA Research Inc., Wheat Ridge, Colorado, USA.
J Biomed Mater Res B Appl Biomater. 2022 May;110(5):991-1000. doi: 10.1002/jbm.b.34972. Epub 2021 Dec 2.
This study tests biodegradation resistance of a custom synthesized novel ethylene glycol ethyl methacrylate (EGEMA) with ester bond linkages that are external to the central polymer backbone when polymerized. Ethylene glycol dimethacrylate (EGDMA) with internal ester bond linkages and EGEMA discs were prepared in a polytetrafluoroethylene (PTFE) mold using 40 μl macromer and photo/co-initiator mixture cured for 40 s at 1000 mW/cm . The discs were stored in the constant presence of Streptococcus mutans (S. mutans) in Todd Hewitt Yeast + Glucose (THYE+G) media up to 9 weeks (n = 8 for each macromer type) and physical/mechanical properties were assessed. Initial measurements EGEMA versus EGDMA polymer discs showed equivalent degree of conversion (45.69% ± 2.38 vs. 46.79% ± 4.64), diametral tensile stress (DTS; 8.12± 2.92 MPa vs. 6.02 ± 1.48 MPa), and low subsurface optical defects (0.41% ± 0.254% vs. 0.11% ± 0.074%). The initial surface wettability (contact angle) was slightly higher (p ≤ .012) for EGEMA (62.02° ± 3.56) than EGDMA (53.86° ± 5.61°). EGDMA showed higher initial Vicker's hardness than EGEMA (8.03 ± 0.88 HV vs. 5.93 ± 0.69 HV; p ≤ .001). After 9 weeks of S. mutans exposure, EGEMA (ΔDTS-1.30 MPa) showed higher resistance to biodegradation effects with a superior DTS than EGDMA (ΔDTS-6.39 MPa) (p = .0039). Visible and scanning electron microscopy images of EGEMA show less surface cracking and defects than EGDMA. EGDMA had higher loss of material (18.9% vs. 8.5%, p = .0009), relative changes to fracture toughness (92.5% vs. 49.2%, p = .0022) and increased water sorption (6.1% vs. 1.9%, p = .0022) compared to EGEMA discs. The flipped external ester group linkage design is attributed to EGEMA showing higher resistance to bacterial degradation effects than an internal ester group linkage design methacrylate.
本研究测试了一种新型合成的乙烯基乙二醇甲基丙烯酸乙酯（EGEMA）的抗生物降解性，该化合物在聚合时具有位于聚合物主链外部的酯键连接。使用聚四氟乙烯（PTFE）模具制备了具有内部酯键连接的二乙二醇二甲基丙烯酸酯（EGDMA）和 EGEMA 圆盘，使用 40μl 大分子单体和光/共引发剂混合物在 1000mW/cm 下固化 40s。圆盘在含有变形链球菌（S. mutans）的 Todd-Hewitt 酵母+葡萄糖（THYE+G）培养基中储存长达 9 周（每种大分子单体类型 n=8），并评估其物理/力学性能。初始测量结果表明，EGEMA 与 EGDMA 聚合物圆盘具有等效的转化率（45.69%±2.38%比 46.79%±4.64%）、直径拉伸应力（DTS；8.12±2.92MPa 比 6.02±1.48MPa）和低亚表面光学缺陷（0.41%±0.254%比 0.11%±0.074%）。EGEMA 的初始表面润湿性（接触角）略高（p≤.012）（62.02°±3.56°）比 EGDMA（53.86°±5.61°）。EGDMA 的初始维氏硬度高于 EGEMA（8.03±0.88HV 比 5.93±0.69HV；p≤.001）。在变形链球菌暴露 9 周后，EGEMA（ΔDTS-1.30MPa）显示出对生物降解作用的更高抵抗力，其 DTS 优于 EGDMA（ΔDTS-6.39MPa）（p=0.0039）。可见和扫描电子显微镜图像显示，EGEMA 的表面裂纹和缺陷比 EGDMA 少。与 EGEMA 圆盘相比，EGDMA 具有更高的材料损失（18.9%比 8.5%，p=0.0009）、相对断裂韧性损失（92.5%比 49.2%，p=0.0022）和更高的水分吸附（6.1%比 1.9%，p=0.0022）。外部酯基团连接设计的翻转归因于 EGEMA 对细菌降解作用的抵抗力高于内部酯基团连接设计的甲基丙烯酸酯。
