天然牙与种植体联合支持套简冠固定桥的骨组织应力分析

目的：研究天然牙与种植体联合支持式套筒冠固定桥牙周组织的应力分布情况。方法：选择1例左侧下颌第一磨牙缺失病例，分别设计以左侧下颌第二前磨牙与种植体（位于下颌第二磨牙）联合支持固定桥模型（模型Ⅰ）和套筒冠固定桥模型（模型Ⅱ）。在分散垂直和分散斜向2种载荷情况下，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：分散垂直载荷下，模型Ⅰ中的天然牙和种植体周围骨组织最大等效应力值分别为2．58MPa和43．92MPa；模型Ⅱ中，相应的最大等效应力值分别为2．17MPa和20．23MPa。分散斜向载荷下，模型Ⅰ中的天然牙和种植体周围骨组织最大等效应力值分别为2．23MPa和46．37MPa；模型Ⅱ中．相应的最大等效应力值分别为1．91MPa和21.19MPa。结论：套筒冠固位体能缓冲种植体周围骨组织的部分应力，但对垂直应力和侧向应力的缓冲能力差别不大。进行天然牙与种植体联合支持固定桥修复时，可在种植体端设计套筒冠固位体．以缓冲种植体周围骨组织的应力水平，防止或减轻种植体支持组织的损伤。

Three dimensional finite element analysis of stress distribution of bone tissues around abutments in telescope fixed bridge supported by tooth-implant

PURPOSE: To study the stress distribution of bone tissues around the abutments in telescope fixed bridge supported by tooth-implant. METHODS: A patient with loss of the left first mandibular molar was used as the subject. Two partial fixed denture models were established. One model (model I) was supported by the second premolar and implant in the second molar, the other model (model II) was supported by the second premolar and implant other than the second molar. Under decentralized vertical and oblique loads, the stress distribution of bone tissues around the tooth and implant was evaluated by three dimensional finite element analysis. RESULTS: Under decentralized vertical load, the max EQVs of the bone tissues around the tooth and implant in model I were 2.58MPa and 43.92MPa, and 2.17MPa and 20.23MPa in model II. Under decentralized oblique load, the max EQVs of the bone tissues around the tooth and implant in model I were 2.23MPa and 46.37MPa, and 1.91MPa and 21.19MPa in model II. CONCLUSIONS: The stress surrounding the implant is declined by the buffer of telescope retainer, and the decline is not different under the two loads. In designing the fixed bridge supported by tooth-implant, we can design telescope retainer on implant to reduce the stress of bone tissues around the implant and to prevent damages to bone tissues.