title: Bond strength and interactions of machined titanium-based alloy with dental cements.
abstract: BACKGROUND
  The most appropriate luting agent for restoring cement-retained implant restorations has yet to be determined. Leachable chemicals from some types of cement designed for teeth may affect metal surfaces.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to evaluate the shear bond strength and interactions of machined titanium-based alloy with dental luting agents.
  
  
  METHODS
  Eight dental luting agents representative of 4 different compositional classes (resin, polycarboxylate, glass ionomer, and zinc oxide-based cements) were used to evaluate their effect on machined titanium-6 aluminum-4 vanadium (Ti-6Al-4V) alloy surfaces. Ninety-six paired disks were cemented together (n=12). After incubation in a 37°C water bath for 7 days, the shear bond strength was measured with a universal testing machine (Instron) and a custom fixture with a crosshead speed of 5 mm/min. Differences were analyzed statistically with 1-way ANOVA and Tukey HSD tests (α=.05). The debonded surfaces of the Ti alloy disks were examined under a light microscope at ×10 magnification to record the failure pattern, and the representative specimens were observed under a scanning electron microscope.
  
  
  RESULTS
  The mean ±SD of shear failure loads ranged from 3.4 ±0.5 to 15.2 ±2.6 MPa. The retention provided by both polycarboxylate cements was significantly greater than that of all other groups (P<.05). The scanning electron microscope examination revealed surface pits only on the bonded surface cemented with the polycarboxylate cements.
  
  
  CONCLUSIONS
  Cementation with polycarboxylate cement obtained higher shear bond strength. Some chemical interactions occurred between the machined Ti-6Al-4V alloy surface and polycarboxylate cements during cementation.
authors.affiliation: Affiliate Faculty, Department of Restorative Dentistry, University of Washington, Seattle, Wash. Electronic address: cpkw1@live.com.
authors.forename: Chandur
authors.initials: C
authors.lastname: Wadhwani
authors.affiliation: Professor, Department of Restorative Dentistry, University of Washington, Seattle, Wash.
authors.forename: Kwok-Hung
authors.initials: KH
authors.lastname: Chung
mesh_terms: D000497:Alloys; D055598:Chemical Phenomena; D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements / Q000737:chemistry*; D033081:Shear Strength; D014025:Titanium / Q000737:chemistry*
chemical_list: D000497:Alloys; D003738:Dental Cements; C031462:titanium alloy (TiAl6V4); D014025:Titanium