title: Investigation of the effect of titanium alloy surface coating with different techniques on titanium-porcelain bonding.
abstract: BACKGROUND
  The bond strength of dental porcelain to titanium is inadequate as a clinical alternative to conventional alloys for metal ceramic restorations.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to evaluate the effects of coating titanium surface with a micro-arc oxidation (MAO) technique and hydroxyapatite (HA) on the bond strength of porcelain to titanium surfaces.
  
  
  METHODS
  One hundred twenty machined titanium specimens with a dimension of 25×3×0.5 mm were prepared from grade 5 titanium as the metal substrate. Specimens were divided into 6 groups (n=20) according to the surface treatment used: airborne-particle abraded (control), coated with MAO for 5 minutes, coated with MAO for 15 minutes, coated with MAO for 30 minutes, coated with HA, and combination of MAO and HA. Each group was further divided into 2 subgroups (n=10) according to the type of porcelain used: Noritake Ti-22 porcelain or Vita-Titankeramik porcelain. The bond strength was tested with a universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed statistically with 2-way ANOVA and Tukey honest significant differences multiple comparison tests (α=.05).
  
  
  RESULTS
  For both porcelain groups, the 30-minute MAO groups showed higher bond strength values than those of the control groups (P<.05). In the Vita Titankeramik porcelain subgroup, the specimens coated with HA did not show any statistical differences compared with those of the control group (P>.05). Surface roughness was affected significantly (P<.001) by the coating procedure compared to that of the the control group.
  
  
  CONCLUSIONS
  Coating with either MAO or HA improved titanium-porcelain adhesion.
authors.affiliation: Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Abant Izzet Baysal University, Bolu, Turkey. Electronic address: maliaslan@yahoo.com.
authors.forename: Muhammed Ali
authors.initials: MA
authors.lastname: Aslan
authors.affiliation: Associate Professor, Department of Prosthodontics, Faculty of Dentistry, Ondokuz Mayis University, Samsun, Turkey.
authors.forename: Cagri
authors.initials: C
authors.lastname: Ural
authors.affiliation: Professor, Department of Orthodontics, Faculty of Dentistry, Biruni University, Istanbul, Turkey.
authors.forename: Selim
authors.initials: S
authors.lastname: Arici
mesh_terms: D000497:Alloys; D001840:Dental Bonding; D003776:Dental Porcelain; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D013499:Surface Properties; D014025:Titanium
chemical_list: D000497:Alloys; D003776:Dental Porcelain; D014025:Titanium