Swain M V
Biomaterials Laboratory, Faculty of Dentistry, University of Sydney, Sydney Dental Hospital, 2 Chalmers St., Surry Hills, NSW 2010, Australia.
Acta Biomater. 2009 Jun;5(5):1668-77. doi: 10.1016/j.actbio.2008.12.016. Epub 2009 Jan 9.
The central argument of this study is that residual stresses developed during the preparation of all-ceramic crowns and fixed partial dentures coupled with contact-induced cracking are the origin of the excessive chipping observed in clinical applications. The aim of this paper is to provide a simple basic analysis of the causes of residual stress development in ceramics and identify the key thermo-mechanical parameters responsible for these stresses and the resultant contact-induced failure. For simplicity, a bilayer planar geometry is considered. The key outcomes are the critical role of thermo-elastic properties and the thickness of the structures. The approach is then used to evaluate the propensity for unstable cracking of a range of crown structures, including substructures of a range of ceramics, and to show that two specific combinations are most prone to this behaviour, namely porcelain fused to glass ceramics and zirconia substrates. In addition, a simple approach for the minimization of the likelihood for such behaviour and chipping is proposed.
本研究的核心观点是，全瓷冠和固定局部义齿制备过程中产生的残余应力以及接触诱发的裂纹是临床应用中观察到的过度崩瓷的根源。本文旨在对陶瓷中残余应力产生的原因进行简单的基础分析，并确定导致这些应力及由此产生的接触诱发失效的关键热机械参数。为简化起见，考虑双层平面几何结构。关键结果是热弹性性能和结构厚度的关键作用。然后，该方法用于评估一系列冠结构（包括一系列陶瓷的子结构）发生不稳定裂纹的倾向，并表明两种特定组合最容易出现这种情况，即烤瓷熔附玻璃陶瓷和氧化锆基底。此外，还提出了一种简单的方法来最小化这种情况和崩瓷发生的可能性。
