氧化锆基牙科材料人工老化后的溶解性和强度。

Solubility and strength of zirconia-based dental materials after artificial aging.

机构信息

Senior Engineer, Nordic Institute of Dental Materials, Oslo, Norway.

出版信息

J Prosthet Dent. 2013 Oct;110(4):281-7. doi: 10.1016/S0022-3913(13)60377-7.

DOI:10.1016/S0022-3913(13)60377-7

PMID:24079563

Abstract

STATEMENT OF PROBLEM

Advanced high-strength dental ceramics based on zirconium oxide are widely used for dental restorations. However, their durability in liquids has been questioned.

PURPOSE

The purpose of this study was to compare the flexure strength of zirconium dioxide materials designed for different sintering techniques before and after surface exposure to an acidic solution and to correlate the dissolution of the materials with strength data.

MATERIAL AND METHODS

An accelerated aging test, immersion in hot (80°C) 4 vol% acetic acid was used to study the solubility of elements from the surface and the effect on the strength of 3 dental zirconia products: DY: Y-TZP material, milled in HIPed state (Denzir); DM: Mg-PSZ material, milled in dense-sintered state (Denzir M); and CY: Y-TZP material, milled from presintered block and then dense-sintered (Cercon base). Disks were prepared with a surface conditioning as for copings provided for dental restorations. After immersion for 1 week, the liquid was analyzed for a range of elements with ICP-MS. Biaxial flexure strength was measured for 3 samples (n=15) of each material: ground on a 20 µm diamond disk without immersion; after 1 week's immersion in acetic acid; and after 1 week's immersion, grinding, and 1 more week in acid. Fracture probability was analyzed by maximum likelihood attribution of individual measurements to 1 or 2 Weibull distributions, each with 2 free parameters.

RESULTS

Dissolution was found to be limited. The total mass loss was less than 0.7 µg/cm(2) for Y-TZP and 3.5 µg/cm(2) for Mg-PSZ. The mean strength was reduced for all materials after immersion in the fluid. Weibull statistics revealed 2 fracture mechanisms in Y-TZP milled in fully sintered condition. For DY only, 2 distributions significantly (P>.99) improved the description of individual treatment data.

CONCLUSIONS

Y-TZP materials showed the highest biaxial flexure strength. Immersion for 1 week in hot 4 vol% acetic acid weakened all 3 zirconia materials by 100 to 200 MPa. Milling in the presintered state resulted in less variability than milling in the HIPed state. Mg-PSZ exhibited the least variability.

摘要

问题陈述

基于氧化锆的高级高强度牙科陶瓷被广泛用于牙科修复。然而，它们在液体中的耐久性受到了质疑。

目的

本研究的目的是比较设计用于不同烧结技术的氧化锆材料在表面暴露于酸性溶液前后的弯曲强度，并将材料的溶解与强度数据相关联。

材料和方法

使用加速老化试验，将样品浸入热（80°C）4%体积的乙酸中，研究从表面溶解的元素以及对 3 种牙科氧化锆产品强度的影响：DY：Y-TZP 材料，在热等静压状态下研磨（Denzir）；DM：Mg-PSZ 材料，在致密烧结状态下研磨（Denzir M）；CY：Y-TZP 材料，从预烧块研磨然后致密烧结（Cercon 基底）。制备圆盘时，对每个材料的 3 个样本（n=15）进行表面处理，使其与牙科修复体的牙冠具有相同的表面条件。浸入 1 周后，用 ICP-MS 分析液体中的多种元素。在未浸入的情况下，用 20 µm 金刚石盘研磨每个样本 3 次；在乙酸中浸入 1 周后；在乙酸中浸入 1 周、研磨后再在酸中浸入 1 周后。通过对个体测量值归因于 1 个或 2 个威布尔分布的最大似然分析来分析断裂概率，每个分布有 2 个自由参数。

结果

发现溶解是有限的。Y-TZP 的总质量损失小于 0.7 µg/cm²，而 Mg-PSZ 的总质量损失小于 3.5 µg/cm²。所有材料在浸入液体后强度均降低。威布尔统计分析显示，在完全烧结状态下研磨的 Y-TZP 有 2 种断裂机制。仅对 DY 而言，2 个分布显著（P>.99）提高了对个体治疗数据的描述。