洞壁倒凹的不同处理对下颌第一磨牙嵌体修复的三维有限元分析  

Three-dimensional Finite Element Analysis of Mandibular First Molar Restored by Inlay with Different Undercut Treatment

作　　者：康小翠 周珊[1] 李晨 燕高飞 张荣[1] 王梅力 张文卿 郭阳[1] KANG Xiaocui;ZHOU Shan;LI Chen;YAN Gaofei;ZHANG Rong;WANG Meili;ZHANG Wenqing;GUO Yang(Department of Stomatology,The Second Affiliated Hospital of Harbin Medical University,Harbin 150000,China;Taiyuan Henglun Stomatological Hospital,Taiyuan 030001,China)

机构地区：[1]哈尔滨医科大学附属第二医院口腔科,黑龙江哈尔滨150000 [2]山西省太原市恒伦口腔医院,山西太原030001

出　　处：《口腔医学研究》2023年第9期827-831,共5页Journal of Oral Science Research

基　　金：黑龙江省高等教育教学改革项目(编号:SJGY20200452)。

摘　　要：目的:通过医学三维有限元数字化建模,探讨当龋洞内有不同大小的倒凹时,采用传统外展预备和留有倒凹的微创预备两种预备方式对嵌体修复的力学影响,以期为临床工作提供理论指导。方法:采用CBCT扫描生成下颌第一磨牙根管治疗O缺损且颊侧壁有半球形倒凹的有限元模型,3种倒凹直径(1、2、3 mm),3种倒凹充填材料(流体树脂、玻璃离子、粘接剂)。采用两种不同的嵌体预备方式(A组为留有倒凹的微创预备,B组为传统外展预备)。比较两组中各结构应力大小和分布情况。结果:(1)两种倒凹的处理对牙齿应力水平有一定影响。在倒凹充填材料和倒凹直径均一致的情况下,垂直加载时A、B两组,牙釉质的应力值基本相同,牙本质的应力值A组略大于B组,修复体应力值B组明显大于A组;斜向加载时B组牙釉质、牙本质和修复体的应力值均大于A组。(2)A组中不同材料充填倒凹后,各结构应力值略有差异,就倒凹层的应力及应变峰值分析,流体树脂应力相对较小且均匀。结论:从生物力学角度看,留有倒凹的微创预备方式有利于保护牙釉质和改善修复体应力,尤其是受到侧向力的情况,但是要保证倒凹冠方有足够的牙本质;倒凹充填材料的选择对整体影响较小,综合来说,流体树脂是比较优良的选择。Objective:To discuss the effects of conventionally divergent preparation and minimally invasive preparation of undercut on inlay through three-dimensional finite element method.Methods:CBCT scanning data were used to establish the model of mandibular first molar restored by inlay with different undercuts diameters(1 mm,2 mm,3 mm).Two preparation methods were performed.Group A was minimally invasive preparation of undercut.Group B was conventionally divergent preparation of undercut.The size and distribution of stress were studied through finite element methods.Results:When filling material and diameter of the concave were the same,the equivalent stress of enamel was the same in group A and group B under vertical loading.The equivalent stress of dentin in group A was slightly larger than that in group B,and the equivalent stress of prosthesis in group B was significantly larger than that in group A.Under oblique loading,the stress of enamel,dentin,and restoration of group B were larger than those of group A.Different undercut filling materials had little effect on the equivalent stress value of enamel,dentin,and restoration.The stress of fluid resin was relatively small and uniform.Conclusion:From the view of biomechanics,the minimally invasive preparation of undercut is beneficial to protect the enamel and improve the stress of prosthesis,especially in the case of lateral loading But attention should be paid to protect the dentin during tooth preparation and root canal treatment.The filling material in the undercut area has little effect on the whole.In general,fluid resin is a better choice.

关 键 词：下颌第一磨牙 倒凹 牙体预备 嵌体 

分 类 号：R782.1[医药卫生—口腔医学]