Effecs of storage in oral cavity simulated envirorment on dental restorative ceramics

本研究对牙科修复陶瓷在口腔模拟环境下的疲劳性能、临床病例的断裂分析以及牙科陶瓷的基本疲劳行为与临床失效之间的关系进行了评价。口腔模拟环境选择37℃的无菌水中存放，采用双轴弯曲试验评价其疲劳行为。在口腔模拟环境中对两种牙科修复陶瓷材料存放一年前后的静态疲劳和循环疲劳进行了测试。铸造陶瓷的静态和循环疲劳性能降低，而热压陶瓷的静态和循环疲劳性能提高。这些现象可能是由于陶瓷表面织构与水的反应造成的，但还需要更详细的研究。目前，人们一直在研究长期保存对牙本质的影响，并对牛牙本质浸泡液对疲劳强度的影响进行了评价，认为浸泡液对疲劳强度的影响不显著。为了评估疲劳性能与临床骨折之间的关系，有必要收集更多的骨折病例。这些结果中的一部分已经在IADR等几个国际科学会议上发表，并准备发表。

In this study, fatigue properties of dental restorative ceramics after oral cavity simulated environment, fracture analysis of clinical case and relationship between basic fatigue behavior and clinical failure of dental ceramics were evaluated. Storage in dilled water at 37 degrees Celsius was selected as oral cavity simulated environment and the biaxial flexural test was employed for evaluating fatigue behavior. Static and cyclic fatigue of two dental restorative ceramics were measured before and after one year storage in oral cavity simulated environment. A castable ceramics exhibited decreases of static and cyclic fatigue properties, while a heat pressable ceramics showed increases of static and cyclic fatigue properties. These phenomena might be due to reaction of surface texture of ceramics with water, but more detailed investigations are required. Effects of longer storage are now continuously investigated.Moreover, the effect of immersion solutions on bovine dentin on fatigue strength was evaluated and the effects of solutions were considered not significant.Regarding clinical case of dental ceramics fracture, number of collected fracture cases were a very few. It was necessary to collect more fracture cases for evaluating relationship between the fatigue properties and clinical fracture.A part of these results were already presented several international scientific meeting such as IADR and preparing for publication.