根管治疗后下颌磨牙采用各种充填材料修复的三维有限元分析

Three-dimensional Finite Element Analysis of Endodontically treated Mandibular Molar Restored with Different Materials

目的:采用三维有限元方法分析比较下颌磨牙根管治疗后各种充填体和垫底材料对牙体应力分布的影响。方法:选用正常形态的下颌第一磨牙,基于Micro CT扫描建立根管治疗后Ⅰ类洞型充填的三维有限元模型。在充填材料面施加200N咬合力的条件下,通过有限元方法分析用不同充填材料进行修复后的牙体组织应力分布状况。结果:银汞合金充填时牙体组织出现的最大拉应力和最大压应力分别是5.75MPa和14.97MPa,明显小于复合树脂充填时牙体组织出现的最大拉应力11.11MPa和最大压应力26.01MPa。复合树脂充填时采用不同垫底材料,牙体组织出现的最大应力数值相近(最大拉应力11MPa±1%,最大压应力26MPa±1%)。结论:成功建立Ⅰ类洞型牙体缺失的下颌磨牙结构的三维有限元模型,实验数据表明,不同充填材料对牙体组织的应力影响较大,而不同垫底材料对牙体组织的应力无显著影响。

Objective： To investigate the influence of different restorative materials on endodontically treated mandibu- lar molar by using three-dimensional finite element method. Methods： A three-dimensional finite element model of a tooth with Class I restoration was established by scanning an extracted normal first mandibular molar after root canal treatment by using micro-CT system. The stress distribution of the teeth with different basing and filling materials under the condition of 200-N occlusal load was carried out by finite element analysis. Results： The maximum values of tensile and compressive strength on the molar restored with amalgam were 5.75MPa and 14.97MPa, and were significantly less than those with composite resin （tensile, 11.11MPa and compressive, 26.01MPa）. The maximum values of tensile and compressive strength of the molar restored with the cement bases are similar, 11MPa＋ 1% （tensile） and 26MPa＋ 1% （compressive）. Conclusion： A three-dimensional finite element model of the first mandibular molar with Class I restoration after root canal treatment was established. Different filling materials significantly influenced the stress distribution of the tooth structures tested, while cement base materials showed no significant effects on the tooth structures tested.