Influence of shading on zirconia's phase transformation and flexural strength after artificial aging

IF 4.6 1区医学 Q1 DENTISTRY, ORAL SURGERY & MEDICINE

Dental Materials Pub Date : 2023-08-01 DOI:10.1016/j.dental.2023.06.005

Sebastian Wille, Rüdiger Möller, Matthias Kern

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引用次数: 0

Abstract

Objectives

The aim of this study was to determine the phase transformation and the influence of aging on the flexural strength of different colored zirconia. The effect of hydrothermal aging in an autoclave was compared with the effect of mechanical stress by simulating chewing.

Methods

High-strength zirconia (3Y-TZP) was investigated in three different colors: uncolored, A3, and D3. Disc-shaped specimens (N = 3) were analyzed by X-ray diffraction (XRD), and flexural strength was determined on bar-shaped specimens (N = 15) in a 4-point bending test before and after performing two different aging protocols: aging in an autoclave (134 °C, 70 h) and aging in a chewing simulator (5 kg load, 1.2 million cycles). During autoclave aging, the fraction of monoclinic phase on the surface was determined every 5 h. Once this exceeded 25 vol%, aging of the bar specimens was stopped.

Results

While in the unstained group the mean value of the proportion of monoclinic phase already exceeded 25 vol% after 30 h in the autoclave, this was the case in both stained groups only after 70 h. No measurable phase transformation could be detected after chewing simulation. Only color A3 showed a statistically significant (p ≤ 0.05) decrease in flexural strength after aging in the chewing simulator.

Significance

The colored zirconia showed a higher resistance to phase transformation through hydrothermal aging. The metal oxides in the staining solutions are assumed to hinder the phase transformation in the zirconia. Therefore, the significant reduction in the stained zirconia after chewing simulation is particularly interesting

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遮光对人工老化后氧化锆相变及抗弯强度的影响

目的研究不同颜色氧化锆的相变及时效对其抗弯强度的影响。通过模拟咀嚼，比较了热压釜中水热老化的影响和机械应力的影响。方法采用无色、A3、D3三种不同颜色的高强度氧化锆(3Y-TZP)进行研究。采用x射线衍射(XRD)分析了圆盘状试样(N = 3)，并对条形试样(N = 15)进行了4点弯曲试验，分别进行了高压灭菌(134°C, 70 h)和咀嚼模拟器(5 kg载荷，120万次)老化前后的抗弯强度测定。在高压灭菌时效过程中，每5小时测定一次表面单斜相的分数。一旦这个分数超过25 vol%，棒材试样的时效就停止。结果未染色组在高压灭菌30 h后，单斜相比例的平均值已超过25 vol%，而两组均在70 h后才出现这种情况，咀嚼模拟后未检测到可测量的相变。在咀嚼模拟器中老化后，只有A3色的抗弯强度下降有统计学意义(p≤0.05)。意义:彩色氧化锆在水热时效过程中表现出较高的抗相变能力。假设染色溶液中的金属氧化物阻碍了氧化锆的相变。因此，咀嚼模拟后氧化锆染色的显著减少是特别有趣的

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来源期刊

Dental Materials 工程技术-材料科学：生物材料

CiteScore

9.80

自引率

10.00%

发文量

290

审稿时长

67 days

期刊介绍： Dental Materials publishes original research, review articles, and short communications. Academy of Dental Materials members click here to register for free access to Dental Materials online. The principal aim of Dental Materials is to promote rapid communication of scientific information between academia, industry, and the dental practitioner. Original Manuscripts on clinical and laboratory research of basic and applied character which focus on the properties or performance of dental materials or the reaction of host tissues to materials are given priority publication. Other acceptable topics include application technology in clinical dentistry and dental laboratory technology. Comprehensive reviews and editorial commentaries on pertinent subjects will be considered.