种植义齿相对位置对食物嵌塞影响的有限元分析

背景:种植义齿是一种固位、支持、稳定功能都很出色的牙修复体,但其种植后的塞牙现象是困扰广大牙列缺损患者的一个普遍现象。目的:应用有限元分析法针对食物嵌塞这一问题进行生物力学数值模拟分析,给出种植义齿的相对宽度、相对高度、相对角度对食物嵌塞影响的定量关系。方法:为研究种植义齿相对牙齿在不同宽度、高度、角度情况下对食物嵌塞的影响,设计了义齿上部结构不同宽度组(分5个亚组:5.6,5.7,5.8,5.9,6.0 mm)、义齿上部结构不同高度组(分5个亚组:6.6,6.8,7.0,7.2,7.4 mm)、义齿不同种植角度组(分5个亚组:92°、91°、90°、89°、88°)、自然牙牙冠不同宽度组(分5个亚组:5.6,5.7,5.8,5.9,6.0 mm)、自然牙牙冠不同高度组(分5个亚组:6.6,6.8,7.0,7.2,7.4 mm)、自然牙不同生长角度组(分5个亚组:92°、91°、90°、89°、88°)4颗牙齿局部牙列模型,每个亚组通过改变第3个牙齿部件的相对位置来设计,其余条件相同。对所有牙列模型进行食物嵌塞数值模拟,并分析牙齿受力形变情况,比较各组间受力前后牙间隙宽度曲线。结果与结论:①随着种植义齿上部结构宽度的增加,义齿受力后水平总位移缓慢减少;当上部结构宽度为5.9-6.0 mm间时,自然牙受力变形后牙间隙迅速减小,此时种植义齿对食物嵌塞的影响趋近于自然牙情况下的食物嵌塞状况;②当义齿上部结构高度低于邻牙时,随着该义齿上部结构高度的增加,受力后牙间隙先增大后减小;当义齿低于邻牙且高度在6.8-7.0 mm之间时,受力后牙间隙迅速减小;③义齿受力前后水平总位移随着种植角度的增加缓慢减小;④结果表明为减小食物嵌塞现象,种植义齿与邻牙间隙应小于0.05 mm,种植义齿上部结构高度应低于邻牙0.2 mm左右,种植角度应约等于90°。

Effect of relative position of planting denture on interdental food impaction: finite element analysis

BACKGROUND:Implant denture is a kind of dental restoration with excellent retention,support and stability.However,the phenomenon of dental fillings after implantation is a common phenomenon that troubles the majority of patients with dental defects.OBJECTIVE:The finite element analysis method was used to analyze the food impaction after planting denture by biomechanical numerical simulation,and find the quantitative relationship between the food impaction and relative width,relative height,relative angle of the denture.METHODS:To study fully relative teeth under the conditions of different widths,heights and angles influence on food embedded plug,we designed different width groups of the upper structure of the denture(5 subgroups:5.6,5.7,5.8,5.9,6.0 mm),different height groups of the upper structure of the denture(5 subgroups:6.6,6.8,7.0,7.2,7.4 mm),different planting angle groups of the denture(5 subgroups:92°,91°,90°,89°,88°),different width groups of natural crowns(5 subgroups:5.6,5.7,5.8,5.9,6.0 mm),different height groups of natural crowns(5 subgroups:6.6,6.8,7.0,7.2,7.4 mm),and different natural tooth growth angle groups(5 subgroups:92°,91°,90°,89°,88°)as a 4-teeth partial denture model.Each subgroup was designed by changing the relative position of the third dental component,with the same remaining conditions.The numerical simulation of food impaction was carried out for all dentition models,and the deformation of the teeth was analyzed.The tooth gap width curves were compared before and after stress between each group.RESULTS AND CONCLUSION:(1)After force,the total horizontal displacement of the denture was slowly reduced with the increase of the width of the upper part of the denture.When the width of the upper structure was between 5.9 and 6.0 mm,the interdental space of the natural tooth was rapidly reduced after the deformation of the tooth.The effect of food impaction was closer to the food impaction condition in the case of natural teeth.(2)When the height of the upper structure of the denture was lower than that of the adjacent teeth,with the increase of the height of the upper structure of the denture,the gap between the teeth increased first and then decreased.When the denture was lower than the adjacent tooth and the height was between 6.8 and 7.0 mm,the tooth space decreased rapidly after the force was applied.(3)The total horizontal displacement decreased slowly with increasing planting angle.(4)The results show that to reduce food impaction,the interdental distance of the implant denture and adjacent teeth should be less than 0.05 mm.The height of the implant denture should be less about 0.2 mm than adjacent teeth,and the planting angle should be about 90°.