title: Comparison of mechanical properties of five commercial dental core build-up materials.
abstract: OBJECTIVE
  This study aimed to evaluate and compare the mechanical properties of five commercial core materials using fracture toughness (FT), Knoop hardness number (KHN), diametral tensile strength (DTS), and dynamic elastic moduli (DEM).
  
  
  METHODS
  Composite material specimens were produced (Rock Core, CosmeCore, ParaCore, MultiCore Flow, and Filtek Supreme Plus). The FT test (n = 15) was performed using notchless triangular prism (NTP) specimens. FT was determined using an Instron testing machine. KHN (n = 3) was evaluated using three indentations applied on each specimen. DTS test (n = 15) was measured using an Instron testing machine. The density. of the specimens (n = 3) was determined by water displacement method. Dynamic Young's, shear moduli, and Poisson's ratio (n = 3) were measured by an ultrasonic method. Statistical analysis was conducted using ANOVA and a Tukey B rank order test (P = 0.05).
  
  
  RESULTS
  Rock Core presented the lowest FT values. Filtek Supreme Plus and CosmeCore exhibited significantly higher KHN values than the rest of the materials. CosmeCore had the highest DTS value, which was statistically significant only compared to Rock Core. For DEM, Filtek Supreme Plus exhibited significantly higher Young's and shear moduli than the rest of the materials (P < 0.05).
  
  
  CONCLUSIONS
  Results demonstrated significant differences in the FT, KHN, and DTS values of the core build-up materials tested. According to the elastic behavior of the core composite materials, Rock Core had the lowest Young's values.
authors.affiliation: Department of Dentistry, University of Alberta, Edmonton, Canada.
authors.forename: Sheila P
authors.initials: SP
authors.lastname: Passos
authors.forename: Anderson P
authors.initials: AP
authors.lastname: Freitas
authors.forename: Sami
authors.initials: S
authors.lastname: Jumaily
authors.forename: Maria Jacinta M C
authors.initials: MJ
authors.lastname: Santos
authors.forename: Amin S
authors.initials: AS
authors.lastname: Rizkalla
authors.forename: Gildo C
authors.initials: GC
authors.lastname: Santos
mesh_terms: D000465:Algorithms; D017609:Barium Compounds / Q000737:chemistry; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D055119:Elastic Modulus; D006244:Hardness; D006801:Humans; D008422:Materials Testing; D055595:Mechanical Phenomena; D008689:Methacrylates / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D011176:Post and Core Technique; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D013718:Tensile Strength; D014520:Urethane / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: D017609:Barium Compounds; D003188:Composite Resins; D003764:Dental Materials; C515951:Filtek Supreme Plus; D008689:Methacrylates; C509715:MultiCore Flow; D011109:Polymethacrylic Acids; C102738:barium glass filler; C528099:diurethane dimethacrylate; C020946:triethylene glycol dimethacrylate; C041979:2,2-bis-(4-(2-methacryloxyethoxy)phenyl)propane; D014520:Urethane; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide