title: Elastic Properties of Lithium Disilicate Versus Feldspathic Inlays: Effect on the Bonding by 3D Finite Element Analysis.
abstract: OBJECTIVE
  To determine the elastic properties of five ceramic systems with different compositions (lithium disilicate vs. feldspathic ceramics) and processing methods and compare the stress distribution in premolars in the interface with inlays made with these systems loaded with the maximum normal bite force (665 N) using 3D finite element analysis (FEA).
  
  
  METHODS
  The elastic properties of five ceramic restoration materials (IPS e.max Press, IPS e.max CAD, Vita PM9, Vita Mark II, Vita VM7) were obtained using the ultrasonic pulse-echo method. Three-dimensional FEA simplified models of maxillary premolars restored with these ceramic materials were created. The models were loaded with a load at the two nodes on the occlusal surface in the middle of the tooth, 2 mm from the outside of the tooth, simulating a loading ball with a radius of 6 mm.
  
  
  RESULTS
  The means values of density (g/cm³), Young's modulus (GPa), and Poison's ratio was 2.6 ± 0.3, 82.3 ± 18.3, and 0.22 ± 0.01 for IPS e.max Press; 2.3 ± 0.1, 83.5 ± 15.0, and 0.21 ± 0.01 for IPS e.max CAD; 2.5 ± 0.1, 44.4 ± 11.5, and 0.26 ± 0.08 for PM9; 2.4 ± 0.1, 70.6 ± 4.9, and 0.22 ± 0.01 for Vitamark II; 2.4 ± 0.1, 63.3 ± 3.9, and 0.23 ± 0.01 for VM7, respectively. The 3D FEA showed the tensile stress at the interface between the tooth and the inlay was dependent on the elastic properties of the materials, since the Vita PM9 and IPS e.max CAD ceramics presented the lowest and the highest stress concentration in the interface, respectively.
  
  
  CONCLUSIONS
  The elastic properties of ceramic materials were influenced by composition and processing methods, and these differences influenced the stress concentration at the bonding interface between tooth and restoration. The lower the elastic modulus of inlays, the lower is the stress concentration at the bonding interfaces.
authors.affiliation: Department of Dental Materials and Prosthodontics, Araraquara School of Dentistry, Univ. Estadual Paulista, Araraquara, Brazil.|Department of Dental Materials and Prosthodontics, Instituto de Ciência e Tecnologia-ICT, Univ Estadual Paulista-UNESP, São José dos Campos, Brazil.
authors.forename: Flávia Zardo
authors.initials: FZ
authors.lastname: Trindade
authors.affiliation: Department of Restorative Dentistry (Prosthodontics), School of Dentistry, Federal University of Santa Maria, Rio Grande do Sul State, Santa Maria, Brazil.
authors.forename: Luiz Felipe
authors.initials: LF
authors.lastname: Valandro
authors.affiliation: Department of Dental Materials Science at ACTA, Universiteit van Amsterdam and Vrije Universiteit, Amsterdam, The Netherlands.
authors.forename: Niek
authors.initials: N
authors.lastname: de Jager
authors.affiliation: Department of Dental Materials and Prosthodontics, Instituto de Ciência e Tecnologia-ICT, Univ Estadual Paulista-UNESP, São José dos Campos, Brazil.
authors.forename: Marco Antônio
authors.initials: MA
authors.lastname: Bottino
authors.affiliation: Department of Dental Materials Science at ACTA, Universiteit van Amsterdam and Vrije Universiteit, Amsterdam, The Netherlands.
authors.forename: Cornelis Johannes
authors.initials: CJ
authors.lastname: Kleverlaan
mesh_terms: D001840:Dental Bonding; D003776:Dental Porcelain / Q000627:therapeutic use*; D003793:Dental Restoration, Permanent / Q000379:methods; D003799:Dental Stress Analysis; D004548:Elasticity; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D007284:Inlays
chemical_list: C493120:lithia disilicate; D003776:Dental Porcelain
keywords: Tooth restoration; dental ceramic; elastic modulus; finite element analysis; inlay; stress distribution