黏滯性質對上顎中門齒受外傷力量的影響

Effects of Damping Properties on the Response of the Maxillary Central Incisor Subjected to a Traumatic Impact Force

姚維正(Cwei-Cheng Yao) ； 蔡吉陽(Chi-Yang Tsai) ； 邱文達(Wen-Ta Chiu) ； 陳玫秀(May-Show Chen) ； 謝松志(Sung-Chih Hsieh) ； 李豪富(Hao-Fu Lee) ； 李勝揚(Sheng-Yang Lee) ； 林哲堂(Che-Tong Lin) ； 黃豪銘(Haw-Ming Huang)

《中華牙醫學雜誌（中文版）》 1卷1期 (2005/03) Pp. 16-24

https://doi.org/10.7106/CJD.200503.0016

摘要

上顎中門齒是臨床上最容易發生被撞擊的牙齒，其受撞後可能發生斷裂、鬆脫或牙髓喪失活性等現象，但到目前為止，有關牙齒受到撞擊力產生挫傷的研究，大多侷限於病理現象、臨床統計與治療技術的探討，對影響牙齒遭受撞擊後反應之力量因素的了解，則顯得相對不足。且多數對齒挫傷機轉分析的研究多以靜態力量來加以模擬，而忽略了牙齒黏滯特性的影響。本研究利用模態測試實驗，量測上顎中門齒的阻尼比，並利用動態有限元素分析法，在輸入不同的阻尼參數下分析阻尼特性對牙齒受動態力量後應力分布之影響。研究結果發現，成人上領中門齒的阻尼比為14.6±3.7%。當結構阻尼係數變大時，動態外力作用所導致的齒內應力較靜態力量作用時為低，且應力最大值有延後發生的趨勢。依據此初步的研究結果，以靜態力量模擬齒挫傷機轉會有高估其應力的問題，而本研究所量測得之牙齒黏滯性質將可以作為未來齒挫傷動態分析的重要參考資料。

關鍵字

上顎中門齒 ； 阻尼比 ； 材料性質 ； 有限元素法 ； 結構阻尼係數

並列摘要

Maxillary central incisors are considered to be the most-frequently involved teeth when an impact occurs. The outcome of such an impact can include crown and root fracture, tooth looseness, and chronic or acute pulp necrosis. Although there have been many studies focusing on dental trauma, most investigations paid attention to the pathology, epidemiology, and clinical treatment. The relationships between the mechanical response of an injured tooth and the characteristics of the applied force are still unclear. This is due, at least in part, to most biomechanical studies of dental trauma using impact models which were simplified to a static load applied to a tooth with elastic properties. In this study, the damping ratio of the maxillary central incisor was measured by means of in vivo modal testing experiments. Then, we used the dynamic finite element method to calculate the response of a tooth impacted by a dynamic force. The effects of the damping properties on the stress distribution of the impacted incisor were evaluated by altering the damping ratio of the finite element model. Our results showed that the damping ratio of the maxillary central incisor was 14.6±3.7%. When the damping ratio of the incisor model was increased, the value of the maximum equivalent stress decreased and the response time was delayed. These results can serve as a useful reference for further advanced studies. Meanwhile, our results revealed that a static dentotraumic analysis ignoring the damping properties of the tooth would result in an overestimation of the stresses in the tissue.

並列關鍵字

maxillary central incisor ； damping ratio ； material properties ； finite element method ； structural damping factor