title: Long-term storage affects adhesion between titanium and zirconia using resin cements.
abstract: OBJECTIVE
  To determine the impact of long-term storage on adhesion between titanium and zirconia using resin cements.
  
  
  METHODS
  Titanium grade 4 blocks were adhesively fixed onto zirconia disks with four resin cements: Panavia F 2.0 (Kuraray Europe), GC G-Cem (GC Europe), RelyX Unicem (3M ESPE), and SmartCem 2 (Dentsply DeguDent). Shear bond strength was determined after storage in a water bath for 24 h, 16, 90, and 150 days at 37°C, and after 6000 cycles between 5°C and 55°C. Fracture behavior was evaluated using scanning electron microscopy.
  
  
  RESULTS
  After storage for at least 90 days and after thermocycling, GC G-Cem (16.9 MPa and 15.1 MPa, respectively) and RelyX Unicem (10.8 MPa and 15.7 MPa, respectively) achieved higher shear bond strength compared to SmartCem 2 (7.1 MPa and 4.0 MPa, respectively) and Panavia F2 (4.1 MPa and 7.4 MPa, respectively). At day 150, GC G-Cem and RelyX Unicem caused exclusively mixed fractures. SmartCem 2 and Panavia F2 showed adhesive fractures in one-third of the cases; all other fractures were of mixed type. After 24 h (GC G-Cem: 26.0, RelyX Unicem: 20.5 MPa, SmartCem 2: 16.1 MPa, Panavia F2: 23.6 MPa) and 16 days (GC G-Cem: 12.8, RelyX Unicem: 14.2 MPa, SmartCem 2: 9.8 MPa, Panavia F2: 14.7 MPa) of storage, shear bond strength was similar among the four cements.
  
  
  CONCLUSIONS
  Long-term storage and thermocycling differentially affects the bonding of resin cement between titanium and zirconia.
authors.forename: Barbara
authors.initials: B
authors.lastname: Cvikl
authors.forename: Mirza
authors.initials: M
authors.lastname: Dragic
authors.forename: Alexander
authors.initials: A
authors.lastname: Franz
authors.forename: Modesto
authors.initials: M
authors.lastname: Raabe
authors.forename: Reinhard
authors.initials: R
authors.lastname: Gruber
authors.forename: Andreas
authors.initials: A
authors.lastname: Moritz
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D005459:Fluorides / Q000737:chemistry; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D033081:Shear Strength; D017655:Silicon Compounds / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry*
chemical_list: D017607:Aluminum Compounds; D003764:Dental Materials; C528107:G-Cem resin cement; D008689:Methacrylates; C438843:Panavia-Fluoro; D011140:Polyurethanes; C483701:Rely X Unicem; D019279:Resin Cements; D017655:Silicon Compounds; D014867:Water; C029824:urethane dimethacrylate luting resin; D015040:Zirconium; D014025:Titanium; C020328:fluoroaluminum silicate; D005459:Fluorides; C028541:zirconium oxide