title: Effect of laser welding on the titanium ceramic tensile bond strength.
abstract: Titanium reacts strongly with elements, mainly oxygen at high temperature. The high temperature of titanium laser welding modifies the surface, and may interfere on the metal-ceramic tensile bond strength.
  
  
  OBJECTIVE
  The influence of laser welding on the titanium-ceramic bonding has not yet been established. The purpose of this in vitro study was to analyze the influence of laser welding applied to commercially pure titanium (CpTi) substructure on the bond strength of commercial ceramic. The influence of airborne particle abrasion (Al2O3) conditions was also studied.
  
  
  METHODS
  Forty CpTi cylindrical rods (3 mm x 60 mm) were cast and divided into 2 groups: with laser welding (L) and without laser welding (WL). Each group was divided in 4 subgroups, according to the size of the particles used in airborne particle abrasion: A - Al2O3 (250 µm); B - Al2O3 (180 µm); C - Al2O3 (110 µm); D - Al2O3 (50 µm). Ceramic rings were fused around the CpTi rods. Specimens were invested and their tensile strength was measured at fracture with a universal testing machine at a crosshead speed of 2.0 mm/min and 200 kgf load cell. Statistical analysis was carried out with analysis of variance and compared using the independent t test (p<0.05).
  
  
  RESULTS
  Significant differences were found among all subgroups (p<0.05). The highest and the lowest bond strength means were recorded in subgroups WLC (52.62 MPa) and LD (24.02 MPa), respectively.
  
  
  CONCLUSIONS
  Airborne particle abrasion yielded significantly lower bond strength as the Al2O3 particle size decreased. Mechanical retention decreased in the laser-welded specimens, i.e. the metal-ceramic tensile bond strength was lower.
authors.affiliation: Department of Prosthodontics and Dental Materials, Ribeirao Preto Dental School, University of Sao Paulo, Ribeirao Preto, SP, Brazil.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Galo
authors.forename: Ricardo Faria
authors.initials: RF
authors.lastname: Ribeiro
authors.forename: Renata Cristina Silveira
authors.initials: RC
authors.lastname: Rodrigues
authors.forename: Valéria de Oliveira
authors.initials: Vde O
authors.lastname: Pagnano
authors.forename: Maria da Glória Chiarello de
authors.initials: Mda G
authors.lastname: Mattos
mesh_terms: D020906:Air Abrasion, Dental / Q000379:methods*; D000704:Analysis of Variance; D002516:Ceramics / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods*; D012994:Dental Soldering / Q000379:methods*; D007834:Lasers; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D013499:Surface Properties; D013718:Tensile Strength; D014025:Titanium / Q000737:chemistry*
chemical_list: D016876:Metal Ceramic Alloys; D014025:Titanium