Leando de Moura Martins, Liliane Motta de Lima, Luciana Mendonça da Silva, Flávia Cohen-Carneiro, Pedro Yoshito Noritomi, Fabio Cesar Lorenzoni
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Subsequently, four 3D crown models were created according to two test groups with two different occlusal thicknesses: (1) LD with 1.0 mm (LD1); (2) LD with 2.0 mm (LD2); (3) LU with 1.0 mm (LU1); and (4) LU with 2.0 mm (LU2). FEA models were constructed using the software Femap (Siemens). A load of 200 N was applied in the axial and oblique (20 degrees) directions for each group, and stress dissipation was viewed using the NEi Nastran software.</p><p><strong>Results: </strong>FEA results demonstrated that the LU crowns dissipated the occlusal load to the tooth structure, whereas the LD material concentrated the load inside the crowns. For the LU material, the lower the occlusal thickness, the higher the stress concentration inside the crown became, and the 2.0-mm occlusal thickness transferred lower stress to the tooth structure. The oblique, rather than the vertical, load caused an increase in the maximum stress concentration at the shoulder margin and axial walls.</p><p><strong>Conclusion: </strong>The higher the Young's Modulus mismatch between the crown material and substrate, the higher the load stress concentration inside the material became. The 2-mm occlusal thickness acted by decreasing the load stress to the tooth substrate. Finally, the axial load delivered more favorable stress transmission to the tooth substrate. The crown material and the occlusal thickness appear to be two factors that affect the mechanical behavior of stress dissipation to the tooth structure.</p>","PeriodicalId":50292,"journal":{"name":"International Journal of Prosthodontics","volume":null,"pages":null},"PeriodicalIF":2.1000,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Crown Material and Occlusal Thickness Affect the Load Stress Dissipation on 3D Molar Crowns: Finite Element Analysis\",\"authors\":\"Leando de Moura Martins, Liliane Motta de Lima, Luciana Mendonça da Silva, Flávia Cohen-Carneiro, Pedro Yoshito Noritomi, Fabio Cesar Lorenzoni\",\"doi\":\"10.11607/ijp.6974\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><strong>Purpose: </strong>To compare the mechanical behavior (stress load dissipation and/or concentration) of posterior crowns made from Lava Ultimate (LU; 3M ESPE) and IPS e.max CAD (LD; Ivoclar Vivadent) using finite element analysis (FEA).</p><p><strong>Materials and methods: </strong>A 3D model of a mandibular first molar was prepared by reducing the occlusal surface by 1 or 2 mm (according to group), the axial walls by 1.5 mm, and using a 0.8-mm-deep shoulder margin as a finish line. A convergence of 6 degrees between opposing walls was set. Subsequently, four 3D crown models were created according to two test groups with two different occlusal thicknesses: (1) LD with 1.0 mm (LD1); (2) LD with 2.0 mm (LD2); (3) LU with 1.0 mm (LU1); and (4) LU with 2.0 mm (LU2). FEA models were constructed using the software Femap (Siemens). A load of 200 N was applied in the axial and oblique (20 degrees) directions for each group, and stress dissipation was viewed using the NEi Nastran software.</p><p><strong>Results: </strong>FEA results demonstrated that the LU crowns dissipated the occlusal load to the tooth structure, whereas the LD material concentrated the load inside the crowns. For the LU material, the lower the occlusal thickness, the higher the stress concentration inside the crown became, and the 2.0-mm occlusal thickness transferred lower stress to the tooth structure. The oblique, rather than the vertical, load caused an increase in the maximum stress concentration at the shoulder margin and axial walls.</p><p><strong>Conclusion: </strong>The higher the Young's Modulus mismatch between the crown material and substrate, the higher the load stress concentration inside the material became. The 2-mm occlusal thickness acted by decreasing the load stress to the tooth substrate. Finally, the axial load delivered more favorable stress transmission to the tooth substrate. The crown material and the occlusal thickness appear to be two factors that affect the mechanical behavior of stress dissipation to the tooth structure.</p>\",\"PeriodicalId\":50292,\"journal\":{\"name\":\"International Journal of Prosthodontics\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.1000,\"publicationDate\":\"2023-05-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"International Journal of Prosthodontics\",\"FirstCategoryId\":\"3\",\"ListUrlMain\":\"https://doi.org/10.11607/ijp.6974\",\"RegionNum\":4,\"RegionCategory\":\"医学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"DENTISTRY, ORAL SURGERY & MEDICINE\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"International Journal of Prosthodontics","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.11607/ijp.6974","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"DENTISTRY, ORAL SURGERY & MEDICINE","Score":null,"Total":0}
引用次数: 0
摘要
目的:比较Lava Ultimate (LU)材料后牙冠的力学性能(应力荷载消散和/或集中);3M ESPE)和IPS e.max CAD (LD);采用有限元分析(FEA)。材料与方法:将下颌第一磨牙的咬合面按组缩小1 ~ 2mm，轴向壁缩小1.5 mm，以0.8 mm深的肩缘为终点线，制作三维模型。在相对的墙壁之间设置了6度的收敛。随后，根据两种不同咬合厚度的两组，制作4个三维冠模型:(1)LD为1.0 mm (LD1);(2) LD为2.0 mm (LD2);(3) LU 1.0 mm (LU1);(4) LU为2.0 mm (LU2)。采用西门子Femap软件建立有限元模型。每组分别在轴向和斜向(20度)方向施加200 N的荷载，使用NEi Nastran软件观察应力消散情况。结果:有限元分析结果表明，LU冠将牙合负荷分散到牙齿结构上，而LD材料将牙合负荷集中在牙冠内部。对于LU材料，咬合厚度越小，冠内应力集中越大，2.0 mm的咬合厚度传递给牙体结构的应力越小。斜荷载导致肩缘和轴壁的最大应力集中增加，而不是垂直荷载。结论:冠材料与基体的杨氏模量失配越大，材料内部的载荷应力集中越大。2mm的咬合厚度降低了对牙基的载荷应力。最后，轴向载荷为齿基提供了更有利的应力传递。牙冠材料和咬合厚度是影响牙结构应力消散力学行为的两个因素。
Crown Material and Occlusal Thickness Affect the Load Stress Dissipation on 3D Molar Crowns: Finite Element Analysis
Purpose: To compare the mechanical behavior (stress load dissipation and/or concentration) of posterior crowns made from Lava Ultimate (LU; 3M ESPE) and IPS e.max CAD (LD; Ivoclar Vivadent) using finite element analysis (FEA).
Materials and methods: A 3D model of a mandibular first molar was prepared by reducing the occlusal surface by 1 or 2 mm (according to group), the axial walls by 1.5 mm, and using a 0.8-mm-deep shoulder margin as a finish line. A convergence of 6 degrees between opposing walls was set. Subsequently, four 3D crown models were created according to two test groups with two different occlusal thicknesses: (1) LD with 1.0 mm (LD1); (2) LD with 2.0 mm (LD2); (3) LU with 1.0 mm (LU1); and (4) LU with 2.0 mm (LU2). FEA models were constructed using the software Femap (Siemens). A load of 200 N was applied in the axial and oblique (20 degrees) directions for each group, and stress dissipation was viewed using the NEi Nastran software.
Results: FEA results demonstrated that the LU crowns dissipated the occlusal load to the tooth structure, whereas the LD material concentrated the load inside the crowns. For the LU material, the lower the occlusal thickness, the higher the stress concentration inside the crown became, and the 2.0-mm occlusal thickness transferred lower stress to the tooth structure. The oblique, rather than the vertical, load caused an increase in the maximum stress concentration at the shoulder margin and axial walls.
Conclusion: The higher the Young's Modulus mismatch between the crown material and substrate, the higher the load stress concentration inside the material became. The 2-mm occlusal thickness acted by decreasing the load stress to the tooth substrate. Finally, the axial load delivered more favorable stress transmission to the tooth substrate. The crown material and the occlusal thickness appear to be two factors that affect the mechanical behavior of stress dissipation to the tooth structure.
期刊介绍：
Official Journal of the European Association for Osseointegration (EAO), the International College of Prosthodontists (ICP), the German Society of Prosthodontics and Dental Materials Science (DGPro), and the Italian Academy of Prosthetic Dentistry (AIOP)
Prosthodontics demands a clinical research emphasis on patient- and dentist-mediated concerns in the management of oral rehabilitation needs. It is about making and implementing the best clinical decisions to enhance patients'' quality of life via applied biologic architecture - a role that far exceeds that of traditional prosthetic dentistry, with its emphasis on materials and techniques. The International Journal of Prosthodontics is dedicated to exploring and developing this conceptual shift in the role of today''s prosthodontist, clinician, and educator alike. The editorial board is composed of a distinguished team of leading international scholars.
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