title: Histological analysis of loaded zirconia and titanium dental implants: an experimental study in the dog mandible.
abstract: OBJECTIVE
  To assess whether or not peri-implant soft tissue dimensions and hard tissue integration of loaded zirconia implants are similar to those of a titanium implant.
  
  
  METHODS
  In six dogs, two one-piece zirconia implants (VC, ZD), a two-piece zirconia implant (BPI) and a control one-piece titanium implant (STM) were randomly placed. CAD/CAM crowns were cemented at 6 months. Six months later, animals were killed and histomorphometric analyses were performed, including: the level of the mucosal margin, the extent of the peri-implant mucosa, the marginal bone loss and the bone-to-implant contact (BIC). Means of outcomes variables were calculated together with their corresponding 95% confidence intervals.
  
  
  RESULTS
  In general, the mucosal margin was located coronally to the implant shoulder. The buccal peri-implant mucosa ranged between 2.64 ± 0.70 mm (VC) and 3.03 ± 1.71 mm (ZD) (for all median comparisons p > 0.05). The relative marginal bone loss ranged between 0.65 ± 0.61 mm (BPI) and 1.73 ± 1.68 mm (ZD) (buccal side), and between 0.55 ± 0.37 mm (VC) and 1.69 ± 1.56 mm (ZD) (lingual side) (p > 0.05). The mean BIC ranged between 78.6% ± 17.3% (ZD) and 87.9% ± 13.6% (STM) without statistically significant differences between the groups (p > 0.05).
  
  
  CONCLUSIONS
  One- and two-piece zirconia rendered similar peri-implant soft tissue dimensions and osseointegration compared to titanium implants that were placed at 6 months of loading. Zirconia implants, however, exhibited a relatively high fracture rate.
authors.affiliation: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, University of Zurich, Zurich, Switzerland.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Thoma
authors.affiliation: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, University of Zurich, Zurich, Switzerland.
authors.forename: Goran I
authors.initials: GI
authors.lastname: Benic
authors.affiliation: Department of Veterinary Clinical Sciences, University of Santiago de Compostela, Lugo, Spain.
authors.forename: Fernando
authors.identifier: http://orcid.org/0000-0002-4130-1526
authors.initials: F
authors.lastname: Muñoz
authors.affiliation: Department of Prosthodontics, Albert-Ludwigs-University, Freiburg, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Kohal
authors.affiliation: Universidad Complutense, Madrid, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Sanz Martin
authors.affiliation: Department of Veterinary Clinical Sciences, University of Santiago de Compostela, Lugo, Spain.
authors.forename: Antonio González
authors.initials: AG
authors.lastname: Cantalapiedra
authors.affiliation: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, University of Zurich, Zurich, Switzerland.
authors.forename: Christoph H F
authors.initials: CH
authors.lastname: Hämmerle
authors.affiliation: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, University of Zurich, Zurich, Switzerland.
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Jung
mesh_terms: D000818:Animals; D003442:Crowns; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D017267:Dental Prosthesis Design; D004285:Dogs; D020007:Implants, Experimental; D008334:Mandible; D016348:Osseointegration; D014025:Titanium; D015040:Zirconium
chemical_list: D015921:Dental Implants; D015040:Zirconium; D014025:Titanium
keywords: bone; crowns (all Mesh terms); dental implants; histology; titanium; zirconium oxide