Influence of annealing temperature on the strength of dental glass ceramic materials
Influence of annealing temperature on the strength of dental glass ceramic materials
复制标题
DOI：
10.1016/j.dental.2004.09.004
复制
发表时间：
2005-07-01
期刊：
影响因子：
5
通讯作者：
Marx, R
中科院分区：
文献类型：
--
作者：
Fischer, H;Hemelik, M;Marx, R
目标.牙科玻璃陶瓷构件由于其制造工艺的原因，经常受到残余应力的影响。为了获得可靠的力学特性，需要无残余应力的试样。残余应力可以通过退火工艺去除。这项工作的假设是，退火温度必须单独选择，以可靠地去除可能的残余应力，而不改变玻璃陶瓷材料的特性。由玻璃陶瓷材料Duceram Opaker制成的努氏压痕试样（Degudent，Hanau，德国国，formerly Ducera，Rosbach，FRG），Empress I（Ivoclar Vivadent，沙安，列支敦士登），In-Ceram氧化铝（Vita Zahnfabrik，巴德萨金根，德国），Optec OPC（Jeneric Pentron，Wellingford，美国）和Vita Omega Opaker（Vita Zahnfabrik，Bad Sackingen，德国）在低于和高于相应玻璃化转变温度的各种温度下退火。测定了退火前后的Weibull强度参数和压痕长度。高温退火后，残余应力的松弛引起的强度增加。在低于玻璃化转变温度100 K的温度下退火后，确定了强度增加的局部最大值。在高于玻璃化转变温度的温度下退火后，微塑性消失。建议在测试之前，在低于相应玻璃化转变温度100 K的温度下对玻璃陶瓷部件进行退火，以确定不受可能的残余应力影响的“真实”机械值。(C)2005年，牙科学院材料。由爱思唯尔有限公司出版。保留所有权利。
Objectives. Dental glass ceramic components are always loaded by residual stresses because of the manufacturing process. For a reliable mechanical characterization, residual stress-free specimens are needed. Residual stresses can be removed by an annealing process. The hypothesis of this work was, that the annealing temperature must be individually chosen to reliably remove possible residual stresses without changing the characteristics of the glass ceramic material.Methods. Knoop-indented specimens made of the glass ceramic materials Duceram Opaker (Degudent, Hanau, Germany, formerly Ducera, Rosbach, FRG), Empress I (Ivoclar Vivadent, Schaan, Liechtenstein), In-Ceram Alumina (Vita Zahnfabrik, Bad Sackingen, Germany), Optec OPC (Jeneric Pentron, Wellingford, USA), and Vita Omega Opaker (Vita Zahnfabrik, Bad Sackingen, Germany) were annealed at various temperatures below and above the respective glass transition temperature. The Weibull strength parameters and the lengths of the indentations before and after annealing were determined.Results. A strength increase caused by relaxation of residual stresses was found after annealing at elevated temperatures. A local maximum of increased strength was determined after annealing at a temperature of 100 K below the glass transition temperature. After annealing at temperatures above the glass transition temperature, microplasticity was observed.Significance. It is recommended to anneal glass ceramic components that are intended to be mechanically characterized at a temperature 100 K below the respective glass transition temperature before testing to determine 'true' mechanical values that are not influenced by possible residual stresses. (C) 2005 Academy Dental Materials. Published by Elsevier Ltd. All rights reserved.