Three-dimensional Finite Element Analysis The Stress In The Mandibular Premolar

While there is an extensive body of literature concerningthe stress distribution of periodontal tissues to variousloadings, there have had few stress analysis of teeth and rootunder these conditions. Combining spiral CT (SCT) scanningtechnology, digital image transfer and transcription, withthree-dimensional finite element method (3-D FEM), asatisfactory 3-D FE model of the mandibular premolar withbiomechanical property is constructed, a research on thefeatures of stress distribution in the mandibular premolarunder different conditions is conducted from thebiomechanical point of view.Our study can be divided into three parts:1. Development of the three-dimnsional finite element modelThe purpose of this part is to construct 3-D FE model ofthe mandibular premolar by means of SCT scanning technology,digital image transfer and transcription, 3-D FEM in order toprovide the model basis for the biomechanical study in themandibular premolar. The result show: The constructed modelhas good morphology. It consists of the tooth, peridentalmembrane, alveolar bone. The elements and nodes of the modelare 3346 and 4401. It can be rotated arbitrarily, which isobserved in any interesting direction and manner throughremoving a part of image freely. Furthermore, we can selectany section or sections in the model to observe free1y, andcan cut out or add in some needed elements in accordance withthe purpose of study.2. Threeedimensiona1 finite e1ement analy8is the stressin the norsi1 mandibular preoo1ar under various loadingsTo investigate the stress distribut ion of norfnalmandibular premolar under various 1oadings, 5 loadings wereapp1 ied respect ively on tip of bucca1 cusp (A), center of thelingua1 incl ined plane of buccal cusp (B), and center ofocclusa1 surface (C), and the maximum tens ive and compress ives tress, and the Von mises of the tooth t issue were ca1culated.The results are as fo11ows: the stresses of premo1ar undervertical 1oadings are 1ower than that under the obliqueloadings. The stress concentrat ion exhibi ted at the cervicalregions When vert ical loadings were app1 ied; under the ob1 iqueloadings, the stress increased great ly and concentrated in theroot. 0bserved cervical s tres s concentrat ion under ver t ica 11oadings corresponded well to the common 1ocation of non-carious cervica1 les ion seen in c1 inica1 s ituations, and roots t res s concent ra t ion under obl ique 1oadings corresponded we 1 1to the feature of vertical root fracture seen in c1inicals ituations. The resu1 ts provide biomechanica1 bases for theNoncar ious cervica1 1es ions and vert ical root fracture.3. Threeedimensiona1 finite e1ement ana1ysis the stress inthe norm1 mandibu1ar premolar under various degree ofperiodonta1 supportThe purpose of this study was to determine the locationsof stress concentrations within a maxi l lary premolar undervarious degree of periodontal support. Four leve1s ofperiodonta1 support reduction were s imulated by varying thesocket depth. Vertical loads of 100N were applied on tip ofbuccal cusp (A), center of the lingual inclined plane ofbuccal cusp (B), and center of occ1usal surface (C). Theresu1ting stresses were moni tored and recorded. RESULTS: thestress are increased and the location of the stressconcentration shifted apical1y as periodontal supportdiminished. Periodontal support reduction shifted thelocation of highest stress away from the cervica1 region tothe root. Therefore, cervica1 s tress concentrat ion is lessl ikely to occur on periodonta1ly compromised teeth comparedto stable teeth.