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

本研究对口腔修复陶瓷在模拟口腔环境下的疲劳性能、临床病例的断口分析以及牙科陶瓷的基本疲劳行为与临床失效的关系进行了评价。选择在37 ℃的蒸馏水中储存作为口腔模拟环境，并采用双轴弯曲试验来评估疲劳行为。对两种牙科修复陶瓷在模拟口腔环境中放置1年前后的静态疲劳和循环疲劳进行了测试。铸造陶瓷表现出静态和循环疲劳性能的下降，而热压陶瓷表现出静态和循环疲劳性能的增加。这些现象可能是由于陶瓷的表面纹理与水的反应，但需要更详细的调查。长期保存的影响目前仍在持续研究中。此外，还评估了浸泡溶液对牛牙本质疲劳强度的影响，认为溶液的影响不显著。关于牙科陶瓷断裂的临床病例，收集到的断裂病例数量很少。目前，已有部分研究成果在国际学术会议上发表，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.