Department of Dental Materials and Fixed Prosthodontics, School of Dental Medicine, Policlinico Le Scotte, Viale Bracci, University of Siena, Siena, Italy.
Clin Oral Implants Res. 2011 Feb;22(2):182-8. doi: 10.1111/j.1600-0501.2010.01979.x. Epub 2010 Sep 10.
The aim of the present study was to evaluate differences in the ultimate fracture resistance of titanium and zirconia abutments.
Twenty titanium fixtures were embedded in 20 resin mandible section simulators to mimic osseointegrated implants in the premolar area. The embedded implants were then randomly divided into two groups. Afterwards, specimens in group A (n=10) were connected to titanium abutments (TiDesign™ 3.5/4.0, 5.5, 1.5 mm), while specimens in group B (n=10) were connected to zirconia abutments (ZirDesign ™ 3.5/4.0, 5.5, 1.5 mm). Both groups were loaded to failure in a dynamometric testing machine. Fractured samples were then analyzed by scanning electron microscopy (SEM).
Group A showed a significantly higher fracture strength than that observed in group B. Group A failures were observed at the screw that connects the abutment with the implant while the abutment connection hexagons were plastically bent by the applied load. Group B failures were a result of abutment fractures. SEM analysis showed that in group A the screw failure was driven by crack nucleation, coalescence and propagation, while in group B, the SEM analysis of failed surfaces showed the conchoidal fracture profile characteristic of brittle materials.
The strength of both tested systems is adequate to resist physiologic chewing forces in the premolar area. Conversely, the titanium and zirconia failure modes evaluated here occurred at unphysiological loads. In addition, because the abutments were tested without crowns, the presented data have limited direct transfer to the clinical situation.
本研究旨在评估钛和氧化锆基台的最终抗折强度的差异。
将 20 个钛种植体嵌入 20 个树脂下颌骨段模拟器中，以模拟前磨牙区的骨整合种植体。然后将植入物随机分为两组。随后，A 组（n=10）的标本连接到钛基台（TiDesign™ 3.5/4.0、5.5、1.5mm），而 B 组（n=10）的标本连接到氧化锆基台（ZirDesign ™ 3.5/4.0、5.5、1.5mm）。两组均在动态测试机上加载至失效。然后通过扫描电子显微镜（SEM）分析断裂的样本。
A 组的断裂强度明显高于 B 组。A 组的失效发生在连接基台和种植体的螺钉处，而基台连接的六角形被施加的负载塑性弯曲。B 组的失效是基台断裂的结果。SEM 分析表明，在 A 组中，螺钉失效是由裂纹成核、聚合和扩展驱动的，而在 B 组中，失效表面的 SEM 分析显示出脆性材料特有的贝壳状断裂形貌。
两种测试系统的强度足以抵抗前磨牙区的生理咀嚼力。相反，这里评估的钛和氧化锆的失效模式发生在非生理负荷下。此外，由于基台未戴冠进行测试，因此所提供的数据与临床情况的直接相关性有限。
