New denture base acrylic resins have been introduced that are specifically formulated for microwave polymerization. Microwave polymerization is a time-efficient procedure, but few studies have evaluated how these new acrylic resin formulations compare with conventionally processed acrylic resins. The purpose of this in vitro study was to compare the stiffness and strength of denture base acrylic resins formulated for microwave polymerization with conventionally processed acrylic resin. Rectangular beams were fabricated from 2 microwave-polymerized denture base acrylic resins, microwave-specific resin (Nature-Cryl MC), resin with the option of microwave polymerization (Diamond D), and a conventionally processed resin as a control (Lucitone 199). Specimens (n=10) were stored in water for 1 week and subjected to a 3-point bend test to determine the flexural modulus (stiffness) and flexural strength before (initial properties) or after 120 000 load cycles. The load cycles, conducted between 5 and 25 N at 2 Hz, simulated 6 months of mastication. Data were analyzed by using 2-way ANOVA, followed by pairwise comparisons (α=.05). The initial flexural modulus (mean ±standard deviation) was conventionally processed resin, 2.65 ±0.33 GPa; microwave-specific resin, 3.01 ±0.20 GPa; and microwave-option resin, 2.63 ±0.04 GPa. After load cycling, the mean flexural modulus was conventionally processed resin, 2.34 ±0.32 GPa; microwave-specific resin, 2.69 ±0.20 GPa; and microwave-option resin, 1.96 ±0.11 GPa. The initial flexural strength was conventionally processed resin, 77.6 ±11.0 MPa; microwave-specific resin, 83.6 ±3.5 MPa; and microwave-option resin, 78.9 ±2.6 MPa. After load cycling, the mean flexural strength was conventionally processed resin, 68.7 ±9.0 MPa; microwave-specific resin, 73.3 ±3.3 MPa; and microwave-option resin, 65.5 ±3.5 MPa. Resin and loading state significantly affected the stiffness and strength (<.01); the interaction resin×state was not significant (≥.558). Microwave-polymerized denture base acrylic resins were comparable in stiffness and strength with conventionally processed acrylic resin. All acrylic resins decreased in stiffness and strength after load cycling. The microwave-specific resin was significantly stiffer and stronger than the other denture base acrylic resins, initially and after 120 000 load cycles.

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传统与微波聚合义齿基托丙烯酸树脂的机械性能

现已推出专为微波聚合而配制的新型义齿基托丙烯酸树脂。微波聚合是一种省时的方法，但很少有研究评估这些新的丙烯酸树脂配方与传统加工的丙烯酸树脂的比较。这项体外研究的目的是比较用于微波聚合的义齿基托丙烯酸树脂与传统加工的丙烯酸树脂的刚度和强度。矩形梁由 2 种微波聚合义齿基托丙烯酸树脂、微波专用树脂 (Nature-Cryl MC)、可选择微波聚合的树脂 (Diamond D) 以及作为对照的常规加工树脂 (Lucitone 199) 制成。将样本 (n=10) 在水中储存 1 周，并进行 3 点弯曲测试，以确定 120 000 次负载循环之前（初始性能）或之后的弯曲模量（刚度）和弯曲强度。负载循环在 5 至 25 N、2 Hz 之间进行，模拟 6 个月的咀嚼。使用双向方差分析（2-way ANOVA）分析数据，然后进行成对比较（α=.05）。初始弯曲模量（平均值±标准差）为常规加工树脂，2.65±0.33 GPa；微波专用树脂，3.01±0.20 GPa；和微波选项树脂，2.63 ±0.04 GPa。负载循环后，常规加工树脂的平均弯曲模量为2.34±0.32 GPa；微波专用树脂，2.69±0.20 GPa；和微波选项树脂，1.96 ±0.11 GPa。常规加工树脂的初始弯曲强度为77.6±11.0MPa；微波专用树脂，83.6±3.5MPa；和微波选项树脂，78.9 ±2.6 MPa。负载循环后，常规加工树脂的平均弯曲强度为 68.7 ±9.0 MPa；微波专用树脂，73.3±3.3MPa；和微波选项树脂，65.5 ±3.5 MPa。树脂和负载状态显着影响刚度和强度（<.01）；树脂×状态的相互作用不显着(≥.558)。微波聚合义齿基托丙烯酸树脂的刚度和强度与传统加工的丙烯酸树脂相当。所有丙烯酸树脂在负载循环后其刚度和强度都会下降。在最初和 120 000 次负载循环后，微波专用树脂明显比其他义齿基托丙烯酸树脂更硬、更坚固。