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Reliability and aging behavior of three different zirconia grades used for monolithic four-unit fixed dental prostheses.
Dental Materials ( IF 5 ) Pub Date : 2020-09-15 , DOI: 10.1016/j.dental.2020.08.002
Benedikt C Spies 1 , Fei Zhang 2 , Christian Wesemann 1 , Maoyin Li 3 , Martin Rosentritt 4
Affiliation  

Objective

To investigate the fracture resistance and phase composition of tooth supported four-unit fixed dental prostheses (FDPs) made from three different zirconia grades after loading and aging.

Methods

Seventy-two FDPs were fabricated from 3Y-TZP, 4Y-PSZ and 5Y-PSZ. This resulted in 24 FDPs per grade, subdivided into three groups (n = 8): a control group (C), a hydrothermally aged (H2O, 85 °C, 90 days) group (A) and a group subjected to loading (2.5M cycles, 98N) with simultaneous thermal cycling (H2O, 5–55 °C) subsequent to treatment A (AL). Subsequently, FDPs were statically loaded to fracture. Phase composition was quantified by X-ray diffraction (XRD) and μ-Raman spectroscopy. Focused ion beam (FIB) - Scanning electron microscopy (SEM) was used for visualization in-depth.

Results

Compared to 3Y-C FDPs (1233 ± 165N), reduced fracture load was found for 5Y-C FDPs (889 ± 80 N; p < .001). This did not apply for 4Y-C samples (1065 ± 111N). Treatments (A, AL) did not negatively affect the fracture load for the three grades of zirconia (p > .645). Both A and AL increased monoclinic phase content for 3Y and 4Y FDPs, whereas FIB-SEM suggests no transformability of 5Y-PSZ. 5Y-AL FDPs showed cracks and fractures at the abutment walls and restoration margins after dynamic loading. Reduced fracture load of 5Y samples as compared to 3Y and 4Y was associated with deficient transformability in the fracture zone.

Significance

Aging and loading did not negatively affect the fracture resistance of monolithic four-unit FDPs made from three grades of zirconia. Due to cracks after dynamic loading, 5Y-PSZ cannot be recommended for the clinical application of four-unit FDPs.



中文翻译:

用于整体式四单元固定义齿的三种不同氧化锆等级的可靠性和老化行为。

目的

为了研究由三种不同氧化锆等级制成的牙齿支撑的四单元固定义齿(FDP)在加载和老化后的抗断裂性和相组成。

方法

由3Y-TZP,4Y-PSZ和5Y-PSZ制成了72个FDP。这导致每个年级有24个FDP,分为三组(n = 8):对照组(C),水热老化(H 2 O,85°C,90天)组(A)和承受负荷的组(2.5M周期,98N),同时在处理A(AL)之后进行同时热循环(H 2 O,5-55°C)。随后,将FDP静态加载以使其断裂。相组成通过X射线衍射(XRD)和μ-拉曼光谱法定量。聚焦离子束(FIB)-扫描电子显微镜(SEM)用于深入可视化。

结果

与3Y-C FDP(1233±165N)相比,发现5Y-C FDP(889±80 N; p <.001)的断裂载荷降低。这不适用于4Y-C样品(1065±111N)。处理(A,AL)对三种等级的氧化锆均无负面影响(P> .645)。A和AL都增加了3Y和4Y FDP的单斜晶相含量,而FIB-SEM表明5Y-PSZ没有可转化性。5Y-AL FDP在动态载荷后在基台壁处出现裂缝和断裂,并在恢复边缘处出现。与3Y和4Y相比,5Y样品的断裂载荷降低与断裂区的可变形性不足有关。

意义

老化和负载不会负面影响由三种等级的氧化锆制成的整体式四单元FDP的抗断裂性。由于动态加载后会出现裂缝,因此不建议将5Y-PSZ用于四单元FDP的临床应用。

更新日期:2020-10-30
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