title: Bone-implant contact at calcium phosphate-coated and porous titanium oxide (TiUnite)-modified oral implants.
abstract: BACKGROUND
  Calcium phosphate (CP)-coated implants are usually referred to as having osteoconductive properties, whereas titanium implants with a native oxide layer are considered less osteoconductive. Often smooth titanium oxides (TOs) are compared to relatively rough CP structures. The objective of this study was to evaluate osteoconduction by comparing bone-implant contact at a relatively smooth, highly crystalline CP coating with a structured, porous TO (TiUnite)-modified surface.
  
  
  METHODS
  Ten adult Hound Labrador mongrel dogs were used. Four titanium implants (Nobel Biocare) with CP-coated (2) or TO-modified (2) surfaces were installed 12 weeks following mandibular premolar and molar teeth extraction. The implants were alternated within and between jaw quadrants in consecutive animals. Mucosal flaps were advanced and sutured leaving the implants in a submerged position. The animals were injected with fluorescent bone labels at 3 and 4 weeks postsurgery, and pre-euthanasia to monitor progress of bone formation. The animals were euthanized at 8 weeks postsurgery and block biopsies were prepared for histologic and histometric analysis.
  
  
  RESULTS
  There were no remarkable differences in bone formation and apparent bone-implant contact comparing the TO-modified and CP-coated surfaces. However, the measured average bone-implant contact was 71% and 57% (P=0.027) for TO-modified and CP-coated implants, respectively.
  
  
  CONCLUSIONS
  We conclude that the TO surface exhibits osteoconductive properties exceeding that of the CP surface. One or several of the chemical and physical properties of the TO surface may result in the remarkable bone formation along its surface. This study indicated that crystallinity and/or chemistry may be important.
authors.affiliation: Temple University School of Dentistry, Philadelphia, PA 19140, USA.
authors.forename: Andreas V
authors.initials: AV
authors.lastname: Xiropaidis
authors.forename: Mohammed
authors.initials: M
authors.lastname: Qahash
authors.forename: Won Hee
authors.initials: WH
authors.lastname: Lim
authors.forename: Richard H
authors.initials: RH
authors.lastname: Shanaman
authors.forename: Michael D
authors.initials: MD
authors.lastname: Rohrer
authors.forename: Ulf M E
authors.initials: UM
authors.lastname: Wikesjö
authors.forename: Jan
authors.initials: J
authors.lastname: Hall
mesh_terms: D000818:Animals; D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D015921:Dental Implants; D004285:Dogs; D008297:Male; D016348:Osseointegration; D013499:Surface Properties; D014025:Titanium
chemical_list: D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D015921:Dental Implants; C009495:titanium dioxide; C020243:calcium phosphate; D014025:Titanium