摘要
目的采用3种不同的设计方式修复根管治疗后牙冠完整的下颌第二前磨牙,观察其牙本质的应力大小及分布情况。方法采用螺旋式CT扫描获取数据,建立下颌第二前磨牙4种情况下的三维有限元模型:1)直接全冠修复;2)用树脂材料充填开髓洞形后全冠修复;3)铸造镍铬合金桩核与全冠修复;4)纤维桩树脂核与全冠修复。在颊尖顶偏颊侧加载,比较牙本质中最大主应力和von Mises应力的大小及分布情况。结果应力计算分析的结果显示:铸造镍铬合金桩修复时,桩尖周围有明显的应力集中区;纤维桩修复时桩尖周的应力集中不明显;无桩设计而直接用树脂材料充填开髓洞形时,其应力大小和分布与对照组基本一致。结论在本实验条件下,与铸造镍铬合金桩相比,纤维桩更适合于下颌前磨牙的桩核冠修复;在下颌前磨牙牙冠部有足够牙体组织的情况下,在根管中放置桩不一定是必须的,直接用树脂材料充填开髓洞形后行全冠修复也是一种可能的选择。
Objective To investigate the stress intensity and distribution in the dentine of intact endodontically treated mandibular second premolar under three different restorations. Methods Four three-dimensional finite element models were constructed by the data of spiral CT： 1）Mandibular second premolar restored directly by full crown; 2） Fill the perforating cavity with resin material and full crown restoration; 3）Cast nickel chromium（NiCr） alloy post core plus full crown restoration： 4）Fiber post and resin core plus full crown restoration. Load was applied on the buccal inclined surface near the top of the buccal cusp and the intensity and distribution of the maximum tensile stress and yon Mises stress in the dentine were compared. Results When the tooth was restored with NiCr alloy post core, an obvious stress concentration area was observed in the dentine next to the top of the post. When the fiber post was used, there was little stress concentration area around the top of the post, and the stress distribution in the dentine was almost the same as the control group. No difference of the intensity and distribution of the stress was found with the control group when no post was used and the perforating cavity was just filled with resin materi- al. Conclusion Compared with cast metal post, fiber post is more suitable for post-core crown restorations. In cases with sufficient coronal tooth substance, post is not absolutely necessary and just filling the perforating cavity with resin material followed by crown restoration can be one of the alternative restorations.
出处
《华西口腔医学杂志》
CAS
CSCD
北大核心
2008年第4期374-377,共4页
West China Journal of Stomatology
关键词
前磨牙
桩核冠
应力分析
三维有限元
premolar
post-core crown
stress analysis： three-dimensional finite element
