Effect Of Mouthguard Thickness And Impact Direction On The Stress Condition Of Maxillary Central Incisors: A Finite Element Analysis

?Objective?To simulate the stress condition of the maxillary central incisor under different impact direction,aiming to evaluate the protective performance of the custom-made EVA mouthguard.?Methods?An oral CT of the volunteer will be taken for analysis and then extract the segment of maxilla,periodontal membrane and maxillary central incisor from oral CT in the computer.Finally,every part will be assembled for the finite element analysis.The experimental variables are:(1)Thickness mouthguard-0.0mm,1.5mm,3.0mm,4.5mm and 6.0mm;(2)The angles between the impact direction and the long axis of the tooth are 30°,60°,90°and 120°.After retrieving the elastic modulus,poisson ratio and density of each part of the model,these parameters will be used to simulate the stress process of maxillary central incisor in Abaqus.Finally,the result of this analysis will be used to calculate the protective performance of the mouthguard.?Results?(1)EVA mouthguard can buffer stress and reduce the maximum stress of enamel and dentin.The protective efficiency of mouthguard is largely determined by its thickness.(2)Mouthguard is more efficient in reducing the stress of crown compared with the root of incisor.(3)The protective efficiency of mouthguard is influenced by the angle between the impact direction and the long axis of the tooth;When the angle is 90°,the protective efficiency is the lowest in this study.(4)The time-maximum stress curve of the teeth is more flat;however,according to this study,the mouthguard can't postpone the time of maximum stress.?Conclusions ?The 3D finite element analysis is one of the effective methods to evaluate protective efficiency of a mouthguard.Mouthguard is a kind of important protection device for oral and maxillofacial region and the protective efficiency of mouthguard is mainly determined by its thickness.The study is focused on calculating the protective efficiency of mouthguard,and this study proves the efficiency varies with the impact direction.When the angle between the impact direction and the long axis is 90°,the protective efficiency is the lowest.Therefore,the impact direction should be considered in further study when we evaluate the protective efficiency of mouthguard.