金属加强丝与义齿基托修理后弯曲强度：不同数目影响的差异

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50 mm×30 mm×2.5 mm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。关键词：金属加强丝；义齿修理；弯曲强度；聚甲基丙烯酸甲酯；口腔生物材料doi:10.3969/j.issn.1673-8225.2010.08.042

Flexural strength of denture bases repaired with

BACKGROUND: Poly methyl methyacrylate (PMMA) has been widely used as a denture base material in dental field for a long time. However, the fracture of acrylic resin dentures is an unresolved problem in prosthodontics. Therefore, how to improve the flexural strength of repaired denture seems to be extremely important.OBJECTIVE: To study the effect of embedding different amounts of metal wires on the flexural strength of repaired denture bases.METHODS: Twenty-five rectangular specimens (50 mm × 30 mm × 2.5 mm) were fabricated using heat-cured acrylic resins and randomly and evenly divided into five groups: A, B, C, D, and E. All specimens were fractured through the use of universal testing machine, and the flexural strengths were tested. Following preparation of fracture surfaces, one to four metal wires were separately embedded in the groups B, C, D, and E. No metal wires were embedded in the group A. All fractured specimens were repaired using self-curing resins. The flexural strengths were measured again using the same testing machine, and the percentages of strength recovery were calculated. RESULTS AND CONCLUSION: After repair, the flexural strengths were obviously reduced (P < 0.01). Compared to group A, the percentages of strength recovery were significantly increased in groups C, D, and E (P < 0.05). There was no significant difference in the percentage of strength recovery among groups C, D, and E (P > 0.05). These results indicate that embedding two to four metal wires can improve the flexural strength of denture bases.