论文部分内容阅读
背景:聚甲基丙烯酸甲酯长期以来作为义齿基托材料在牙科领域得到了广泛应用,然而义齿折裂是修复学至今尚未解决的难题。因此,如何增强义齿修理后的弯曲强度显得尤为重要。目的:研究加入不同数目的金属加强丝对义齿基托修理后弯曲强度的影响。方法:用聚甲基丙烯酸甲酯热凝树脂制作25个50mm×30mm×2.5mm的长方体试件,将试件在万能试验机上压断,测得其弯曲强度。各组试件断面经预备后分别加入1~4根不锈钢丝,未加入钢丝组为对照组,并用自凝树脂修理裂缝,测定修理后试件的弯曲强度,计算强度恢复率。结果与结论:各组试件修理后的弯曲强度均明显低于修理前(P<0.01)。除加入1根钢丝组外,其余各组强度恢复率均高于对照组(P<0.05)。加入2,3,4根钢丝各组间强度恢复率比较,差异无显著性意义(P>0.05)。结果证实加入2~4根金属加强丝可增强义齿基托修理后的弯曲强度。
BACKGROUND: Polymethylmethacrylate (MDMA) has long been used as a denture base material in the dental field. However, the denture fracture has not been solved yet. Therefore, how to enhance bending strength after denture repair is particularly important. Objective: To study the effect of adding different numbers of metal reinforcing wires on flexural strength of dentures. Methods: 25 pieces of 50mm × 30mm × 2.5mm rectangular parallelepiped specimens were made by using polymethylmethacrylate thermosetting resin. The specimens were pressed on a universal testing machine and the bending strength was measured. The cross sections of the specimens were prepared by adding 1 to 4 stainless steel wires after the preparation. The steel wires were not added as the control group. The self-curing resin was used to repair the cracks. The bending strength of the specimens after repair was measured and the strength recovery rate was calculated. RESULTS AND CONCLUSION: The flexural strength of the specimens after repair was significantly lower than that before repair (P <0.01). In addition to adding a steel wire group, the rest of the intensity recovery rate were higher than the control group (P <0.05). There was no significant difference between the two groups in the strength recovery rate of 2,3,4 wires (P> 0.05). The results confirmed that adding 2 to 4 metal reinforcing wire can enhance the flexural strength of the denture base repair.