ABSTRACT
Objective:To analyse the stress distribution of the tooth and inlay with the restoration of resin,porcelain,gold alloy,co-balt chromium materials respectively.Methods:3-D finite element models of mandibular first molar with meiso-occlusal (class II) cavity and different inlays were established.Von-mises stress distribution on the tooth and inlay with vertical load and lingual load at 45°were analyzed.Results:After restoration peak stress of high elastic module materials and dental inlays was higher than that of the low elastic module material inlays,however,the restorations of the different elastic module materials had the similar stress distribution trend.The stress under of lateral load(lingual at 45°)to the teeth inlays was significantly higher than that under vertical load.Peak stress concentration of tooth was on the bottom of the cavity near the pulp chamber dentin;inlay peak stress distribution is mainly in its corresponding to the gingival wall.In the tooth tissues stress level of the contact surface of inlay restoration,the strength was as the fol-lowing:Composite resin inlay >ceramics inlay >the gold alloy ceramics inlay >cobalt chromium alloy inlay.The stress level of the inlay of the four kinds of inlay restoration materials was just opponent with the tooth tissues.Conclusion:Gingival wall is the weakest part of meiso-occlusal(class II)cavity inlay restoration,while near the pulp chamber at the bottom of the cavity is the weakest part of the tooth.Among the 4 materials Under the same load condition,composite resin inlay restoration has minimal tooth stress and uniform stress distribution,and can reduce the posibility of odontoschism and microleakage.
ABSTRACT
ABSTRACT:Objective To analyze the stress changes of tooth tissues in the medial-occlusal (Class Ⅱ)cavity restored with different kinds of inlay materials by the three-dimensional (3-D)finite element.Methods The inlay restored 3-D finite element model of medial-occlusal (Class Ⅱ)cavity was established by CBCT scanning method and reverse engineering software Mimics,Geomagic Studio,Pro/E5.0 software,and finite element analysis software. The Von-mises stress and change tendency of tooth tissues and four different kinds of inlay materials were compared after taking vertical loading and tongue 45°to loading.Results There were different stress levels of tooth tissues among different inlays of medial-occlusal (MO)Class Ⅱ cavity.The stress level of the cobalt chromium alloy inlay was the largest,the stress level of the gold alloy inlay was lower,and the stress level of the composite inlay was the lowest.Dental tissues stress distribution was similar for the four different restorative materials,and focused on hole bottom of dentin near the pulp in dentin.Conclusion Compared with ceramics,gold alloy and cobalt chromium inlay restoration,restoration with composite resin inlay can reduce the organization stress of the remaining tooth in the medial-occlusal (Class Ⅱ)cavity type.