Department of Prosthodontics, Manav Rachna Dental College, Faridabad, Haryana, India, Phone: +91 7838408622, e-mail:
Department of Prosthodontics, Centre for Dental Education & Research, AIIMS, New Delhi, India.
J Contemp Dent Pract. 2022 Aug 1;23(8):788-792. doi: 10.5005/jp-journals-10024-3387.
The purpose of this study was to evaluate the flexural strength of heat polymerized denture base resin after thermocycling and different surface treatments done prior to repair or relining.
In this study, 80 specimens were made with heat-polymerized denture base resin and thermocycled (500 cycles between 5 and 55 °C). The specimens were divided in four groups based on different types of surface treatment: group I (control group: without surface treatment), group II (chloroform for 30 seconds), group III [methyl methacrylate (MMA) for 180 seconds], and group IV (dichloromethane for 15 seconds). The flexural strength was assessed using a Universal testing machine with three-point bending test. The obtained data were subjected to statistical analysis using one-way ANOVA and tests.
The values of average flexural strength of denture base resin measured were as follows: group I: 111.1 MPa, group II: 86.9 MPa, group III: 73.1 MPa, and group IV: 78.8 MPa. Groups II and IV possessed superior flexural strength than group III. The maximum values were observed with the control group.
The flexural strength of heat-polymerized denture base resin gets affected by different surface treatments done prior to relining procedures. Lowest flexural strength was obtained when treated with MMA monomer for 180 seconds as compared to the other etchants used.
Prior to denture repair procedures, operators must choose the chemical surface treatment judiciously. It should not affect the mechanical properties such as flexural strength of denture base resins. Reduction in flexural strength of polymethyl methacrylate (PMMA) denture base can predispose the prosthesis to deteriorated performance when in function.
本研究旨在评估热聚合义齿基托树脂在热循环和修复或衬里前不同表面处理后的弯曲强度。
在这项研究中，用热聚合义齿基托树脂制作了 80 个样本，并进行了热循环（在 5 至 55°C 之间进行 500 次循环）。根据不同的表面处理类型，将样本分为四组：I 组（对照组：无表面处理）、II 组（氯仿 30 秒）、III 组（甲基丙烯酸甲酯（MMA）180 秒）和 IV 组（二氯甲烷 15 秒）。使用三点弯曲试验的万能试验机评估弯曲强度。使用单向方差分析和 t 检验对获得的数据进行统计分析。
义齿基托树脂平均弯曲强度的测量值如下：I 组：111.1 MPa，II 组：86.9 MPa，III 组：73.1 MPa，IV 组：78.8 MPa。II 组和 IV 组的弯曲强度优于 III 组。控制组的最大值。
在衬里程序之前进行的不同表面处理会影响热聚合义齿基托树脂的弯曲强度。与使用的其他蚀刻剂相比，用 MMA 单体处理 180 秒时，获得的弯曲强度最低。
在进行义齿修复程序之前，操作人员必须明智地选择化学表面处理。它不应影响义齿基托树脂的机械性能，如弯曲强度。聚甲基丙烯酸甲酯（PMMA）义齿基托的弯曲强度降低会使修复体在功能时性能恶化。
