Graduate student, Department of Prosthodontics and Research Institute of Oral Science, College of Dentistry, Gangneung-Wonju National University, Gangneung, Republic of Korea.
Associate Professor, Department of Prosthodontics and Research Institute of Oral Science, College of Dentistry, Gangneung-Wonju National University, Gangneung, Republic of Korea.
J Prosthet Dent. 2022 Dec;128(6):1319.e1-1319.e10. doi: 10.1016/j.prosdent.2022.09.018. Epub 2022 Nov 3.
Studies that compared the fracture strength of monolithic lithium disilicate and 5-mol% yttria partially stabilized zirconia multiunit fixed dental prostheses are sparse.
As the connector is the weakest part of a fixed dental prosthesis, the purpose of this in vitro study was to investigate the effect of connector designs and material on the fracture strength of 3-unit monolithic fixed dental prostheses.
Resin-ceramic canine and premolar teeth (N=144) were prepared for fixed dental prosthesis abutments. Prostheses with 3 connector designs (width=height, width<height, and width>height) were made from 2 types of lithium disilicate (IPS e.max CAD and Amber Mill) and 5-mol% yttria partially stabilized zirconia (3M Lava Esthetic and Katana Zirconia UTML). Fracture strengths were measured after 200 000 cycles of dynamic loading of 50 N and thermocycling at 5 °C and 55 °C, and the fracture patterns were analyzed. Two-way analysis of variance and the Fisher exact test were used for statistical analysis (α=.05).
The material and connector design affected the fracture strength of fixed dental prostheses (P<.05), and a significant interaction was found between the material and connector design (P<.05). The IPS e.max CAD material had significantly lower fracture strength than Amber Mill, 3M Lava Esthetic, or Katana Zirconia UTML (P<.05). Connector designs with a greater width versus height showed significantly lower fracture strengths than other designs (P<.05).
The connector design of 3-unit fixed dental prostheses, particularly the connector height, may affect fracture strength depending on the prosthesis material.
比较整体式二硅酸锂和 5mol%氧化钇部分稳定氧化锆多单位固定义齿修复体的断裂强度的研究较少。
由于连接器是固定义齿的最薄弱部分，本体外研究的目的是研究连接器设计和材料对 3 单位整体式固定义齿修复体断裂强度的影响。
为固定义齿基牙制备树脂陶瓷犬齿和前磨牙（N=144）。制作了 3 种连接器设计（宽度=高度、宽度<高度和宽度>高度）的义齿，材料为 2 种二硅酸锂（IPS e.max CAD 和 Amber Mill）和 5mol%氧化钇部分稳定氧化锆（3M Lava Esthetic 和 Katana Zirconia UTML）。在 50N 动态加载和 5°C 和 55°C 热循环 200000 次后测量断裂强度，并分析断裂模式。使用双向方差分析和 Fisher 确切检验进行统计分析（α=.05）。
材料和连接器设计影响固定义齿的断裂强度（P<.05），并且在材料和连接器设计之间发现了显著的相互作用（P<.05）。IPS e.max CAD 材料的断裂强度明显低于 Amber Mill、3M Lava Esthetic 或 Katana Zirconia UTML（P<.05）。宽度与高度之比较大的连接器设计的断裂强度明显低于其他设计（P<.05）。
3 单位固定义齿的连接器设计，特别是连接器高度，可能会根据义齿材料影响断裂强度。
