A Study of Reliability Analysis of Fatigue Life for Dental Implants

人工牙根疲勞壽命可靠度分析之研究

蔡有藤(Yuo-Tern Tsai) ； 王國雄(Kuo-Shong Wang)

《中國機械工程學刊》 36卷5期 (2015/10) Pp. 439-448

摘要

人工牙根廣泛地用在缺齒病人恢復咀嚼功能，他的疲勞壽命在國際標準(ISO 14801)有明確規範用以確保品質。本文研究人工牙根疲勞壽命可靠度估計法，建立恆定負荷和隨機負荷疲勞壽命估計模式，利用線性迴歸進行壽命趨勢估計，估計人工牙根在不同循環負荷下之疲勞壽命。為預估人工牙根在動態試驗之破壞點，本研究建立人工牙根及試驗3D 模型，利用ANSYS 分析人工牙根在不同負荷下之應力分佈，分析結果顯示人工牙根最大應力發生在支台(Abutment)頸部，即支台將比基座(Fixture)先發生破壞。此外，本文介紹人工牙根動態試驗和試驗數據收集方法，分析不同負荷位準下取得之壽命數據，利用Mintab 進行實驗數據統計分析，利用機率分佈建立可靠度壽命估計模式，比較四種機率分佈(指數、偉伯、常態、對數常態)在壽命估計之差異；研究結果顯示線性估計模式為一直接有效率的壽命預估法，對數常態(Lognormal)模式較適合用於疲勞壽命可靠度預估，特別是在低的循環負荷。

並列摘要

Dental implants (DIs) were extensively utilized on edentulous patients for recovering the chewing functions. The fatigue life of DIs was definitely specified to ensure the expected lifespan as well as the quality. This paper proposed the methods of reliability life estimation for DIs. The life estimation models are developed including constant amplitude and random loadings. The geometry models of the DIs were constructed for performing stress analysis by finite element methods. The tested steps and the specifications of DIs were reported for fulfilling dynamic testing and collecting the experimental data. The life estimation models are formulated in cooperation with linear regression methods. Four types of probabilistic distributions are used to calculate the probabilistic lives of DIs based on the characteristic parameters of the life distributions. The evaluated errors are compared to formulate the trend lines of the characteristic parameters changing. The studied results show that the direct linear estimation is an efficient approach to predict the fatigue lives as well as the lognormal function is more suitable for the probabilistic lives, especially at the low cyclic loadings.

並列關鍵字

Reliability analysis ； dynamic testing ； dental implants