三种支持类型固定义齿负载时基牙周围骨组织应力分析

目的研究三种支持形式固定义齿在载荷情况下基牙周围骨组织应力分布情况。方法选择1位右侧下颌第一磨牙缺失的志愿者,进行固定义齿修复后,建立天然牙支持式固定义齿三维有限元模型(模型Ⅰ),运用建模软件将模型Ⅰ中的天然牙根替换为种植体,分别建立天然牙与种植体联合支持式固定桥模型(模型Ⅱ)和种植体支持式固定义齿模型(模型Ⅲ)。在分散垂直和分散斜向下加载200N,采用三维有限元法分析基牙及种植体周围骨组织的应力分布情况。结果种植体支持式固定义齿种植体周围骨组织应力最高,且明显集中于种植体颈部;天然牙支持式固定义齿基牙周围骨组织应力最小,且分布较为均匀。斜向加载可以提高固定义齿基牙周围骨组织应力,并增加应力分布的集中程度。结论天然牙支持是固定义齿修复理想的支持形式,在进行各种支持形式固定义齿修复时,都应尽量减小侧向力对支持组织的破坏。

Stress analysis of bone tissues around the abutments of the fixed partial denture supported by three forms under loading

Objective To investigate the stress distribution of bone tissues around the abutments of the fixed partial denture（FPD） supported by three forms. Methods A volunteer with loss of the right first mandibular molar was selected as the subject. After FPD rehabilitation, the three dimensional finite element modal of tooth supported FPD （ model I ） was established. Then, the tooth in the model I was replaced with implant using modeling software, and tooth- implant supported FPD （model 11 ） as well as implant supported FPD （ model HI ） were established respectively. Under decentralized vertical and oblique loads with 200N, the stress distribution of bone tissues around the tooth or implant was evaluated by three dimensional finite element analysis. Results The max EQV of the bone tissues around implant in the model llI was highest, while that in the model I was lowest. The stress contribution around the implant was more concentrated in the bone tissues of the implant cervical part, while the stress was evenly distributed around the tooth. The oblique loading could increase the stress and its concentration of bone tissue around the abutment of FPD. Conclusions Tooth supported FPD was a better supporting way for the FPD rehabilitation. While designing the FPD rehabilitation supported by different forms, it should try to minimize the damages to the supporting tissues under the lateral force.