title: Low Energy Surface Activation of Zirconia Based Restorations.
abstract: OBJECTIVE
  To evaluate the influence of low energy surface activation technique on the biaxial flexure strength of zirconia frameworks.
  
  
  METHODS
  Zirconia discs were prepared by cutting CAD/CAM zirconia blocks. Sintered discs were airborne particle abraded using one of the following particles: 30 μm alumina particles, 50 μm alumina particles, or modified round edges 30 μm alumina particles at low pressure. Scanning electron microscopy, x-ray diffraction analysis, surface roughness, and biaxial flexure strength tests were performed (n = 20). Fractured specimens were fractographically analyzed (α = 0.05).
  
  
  RESULTS
  Low energy surface activation resulted in 7% monoclinic crystallographic transformation, increasing surface roughness from 0.05 to 0.3 μm and in significant increase in biaxial flexure strength (1718 MPa) compared 30 μm (1064 MPa), 50 μm (1210 MPa), and as-sintered specimens (1150 MPa).
  
  
  CONCLUSIONS
  Low energy surface activation of zirconia specimens improved the biaxial flexure strength of zirconia frameworks without creation of surface damage. Clinical implications: by controlling particle size and shape of alumina, the flexure strength of zirconia restorations could be increased usinglow pressure particle abrasion.
authors.forename: Moustafa N
authors.initials: MN
authors.lastname: Aboushelib
mesh_terms: D020906:Air Abrasion, Dental / Q000379:methods; D000537:Aluminum Oxide / Q000737:chemistry; D017076:Computer-Aided Design; D003461:Crystallography; D045662:Dental Etching / Q000379:methods; D003764:Dental Materials / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D018583:Pliability; D011312:Pressure; D013314:Stress, Mechanical; D013499:Surface Properties; D014961:X-Ray Diffraction; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003764:Dental Materials; D015040:Zirconium; D000537:Aluminum Oxide; C028541:zirconium oxide