Department of Prosthodontics, Faculty of Dentistry, Jordan University of Science and Technology (JUST), Irbid, Jordan.
Department of Prosthodontics, Faculty of Dentistry, Jordan University of Science and Technology (JUST), Irbid, Jordan.
J Mech Behav Biomed Mater. 2023 Jan;137:105547. doi: 10.1016/j.jmbbm.2022.105547. Epub 2022 Nov 7.
The purpose of this in-vitro study was to investigate the effect of framework design on fracture resistance and failure modes of cantilever inlay-retained fixed partial dentures (IRFDPs) fabricated from two multilayered monolithic zirconia materials.
Seventy-two natural premolar teeth were prepared as abutments for cantilever IRFDPs using three designs: mesial-occlusal (MO) inlay with short buccal and palatal wings (D1), MO inlay with long palatal wing (D2), MO inlay with long palatal wing and occlusal extension (D3). Full-contoured IRFDPs were fabricated from two monolithic zirconia materials; IPS e.max ZirCAD Prime and Zolid Gen-X. Adhesive surfaces were air-abraded and bonded with MDP-containing resin cement. Specimens were subjected to thermocycling (5-55 °C, 5000 cycles); then, mechanical loading (1.2 × 10⁶ cycles, 49 N). Surviving specimens were loaded until failure in the universal testing machine. All specimens were examined under stereomicroscope, and two samples from each group were evaluated using Scanning Electron Microscope.
Mean failure loads were not significantly different between different framework designs or between two materials. However, IPS e.max ZirCAD Prime showed significantly higher failure rate than Zolid Gen-X during dynamic fatigue (p = 0.009). Samples with D1 design showed higher debonding rate, D2 failed mainly by fracture of the palatal wing and debonding, and D3 failed mainly by fracture of the abutment tooth. Debonded restorations showed mainly mixed failures.
Cantilever IRFDPs with framework designs that maximize adhesion to enamel exhibited promising results. IPS e.max ZirCAD Prime was more susceptible to fractures with the long palatal wing design.
本体外研究旨在探讨框架设计对两种多层整体氧化锆材料制作的悬臂嵌体保留式固定局部义齿（IRFDP）的抗折强度和破坏模式的影响。
将 72 颗天然前磨牙制备为悬臂 IRFDP 的基牙，采用三种设计：近中-牙合嵌体，短颊侧和腭侧翼（D1）；近中-牙合嵌体，长腭侧翼（D2）；近中-牙合嵌体，长腭侧翼和牙合面扩展（D3）。采用两种整体氧化锆材料：IPS e.max ZirCAD Prime 和 Zolid Gen-X 制作全饰面 IRFDP。黏接面喷砂并用含 MDP 的树脂水门汀黏接。试件进行热循环（5-55°C，5000 次）；然后进行机械加载（1.2×10⁶ 次，49N）。存活试件在万能试验机上加载至失效。所有试件在体视显微镜下检查，每组两个样本用扫描电子显微镜评估。
不同框架设计或两种材料之间的平均失效负荷无显著差异。然而，在动态疲劳时，IPS e.max ZirCAD Prime 的失效率明显高于 Zolid Gen-X（p=0.009）。D1 设计的样本显示更高的离脱率，D2 主要通过腭侧翼和离脱断裂失效，D3 主要通过基牙断裂失效。离脱的修复体主要表现为混合失效。
最大限度黏接釉质的悬臂 IRFDP 框架设计具有良好的效果。具有长腭侧翼设计的 IPS e.max ZirCAD Prime 更容易发生断裂。
