论文部分内容阅读
目的:通过对3种偏唇解剖类型上颌中切牙进行三维有限元分析,分析不同类型上颌中切牙牙本质及牙周膜应力分布的情况,为行即刻种植时手术位点的确定提供参考依据。方法:选取符合天然上颌中切牙偏唇类3种不同解剖分型的CBCT数据,利用Mimics等软件建立上颌中切牙及颌骨的三维实体模型及三维有限元模型,利用Ansys软件并模拟咬合力对以上模型施加0°、30°、45°、60°、90°共5种角度的静态载荷力,同时分别计算测定釉牙骨质界-根尖部唇侧、腭侧、近中、远中共4条线上的应力值与位移值及上颌中切牙牙周膜的等效应力值。结果:4条线等效应力、位移及牙周膜等效应力均随着加载力角度的增大而增大。在釉牙骨质界下0.4 mm~2.3 mm的范围内出现4条线等效应力峰值,且总体上各等效应力越到根尖部而越小;由Ⅰ亚类到Ⅲ亚类,等效应力峰值出现位置逐渐向牙颈部方向偏移。Ⅲ亚类上颌中切牙中4线等效应力波动范围最广,峰值最高。4线位移值在牙颈部最高,从颈部至釉牙骨质界下约6 mm~7.5 mm范围内位移下降的趋势最大,在秞牙骨质界下8 mm至根尖范围内趋于平缓。其中,Ⅲ亚类上颌中切牙中四线等效应力波动范围最广,峰值最高;牙周膜等效应力及最大主应力也较Ⅰ亚类、Ⅱ亚类大。结论:由Ⅲ亚类到Ⅰ亚类,在相同大小、方向的力作用下,上颌中切牙承受应力呈减小趋势,且应力最大区域向根方偏移。
OBJECTIVE: To analyze the stress distribution of dentin and periodontal ligament in three types of maxillary central incisor by three-dimensional finite element analysis of three kinds of labial maxillary central incisor, and to provide a reference for the determination of surgical site in immediate implant . Methods: CBCT data of 3 different anatomical types of natural maxillary central incisor partial lip were selected. Three-dimensional solid model and three-dimensional finite element model of maxillary central incisor and maxilla were established by software Mimics. Ansys software was used to simulate occlusion The static loading force of 5 angles of 0 °, 30 °, 45 °, 60 ° and 90 ° was applied to the above models. The effects of the stress on the cementum of the enamel - apical, palatal, Stress and displacement of 4 lines and the equivalent stress of periodontal ligament in maxillary central incisor. Results: The equivalent stress, displacement and periodontal membrane equivalent stress of 4 lines all increased with the increase of loading force. In the range of 0.4 mm ~ 2.3 mm under the cementum of enamel, four lines of equivalent stress peaks appear, and the equivalent stress decreases to the apical part and the smaller; from Ⅰ subclass to subclass Ⅲ, etc. Peak position of effective stress is gradually shifted to the direction of the tooth neck. Ⅲ submaxillary maxillary central incisors in the four-wire equivalent stress fluctuations in the widest range, the highest peak. The displacement of 4-line was the highest in the cervical part of the tooth, and the displacement decreased from about 6 mm to 7.5 mm from the neck to the glazed cementum. The maximal displacement was in the range of 8 mm to apical range gentle. Among them, the maximal median stress of the four-line maxillary central incisor was the highest and the peak was the highest. The equivalent stress and maximum principal stress of the periodontal ligament were also larger than those of the subclasses I and II. CONCLUSION: The bearing stress of the maxillary central incisor tends to decrease with the same magnitude and direction from the subclass Ⅲ to subclass I, and the area with the largest stress is deviated to the root.