title: Bone regeneration at implants with turned or rough surfaces in self-contained defects. An experimental study in the dog.
abstract: BACKGROUND
  Marginal hard tissue defects present at implants with a rough surface can heal with a high degree of bone fill and osseointegration. The healing of similar defects adjacent to implants with a smooth surface appears to be less predictable.
  
  
  OBJECTIVE
  The aim was to compare bone healing at implants with turned or rough surface topographies placed in self-contained defects using either a submerged or non-submerged installation technique.
  
  
  METHODS
  Six dogs were used. Three months after tooth extraction four experimental sites were prepared for implant installation in both sides of the mandible. The marginal 5 mm of the canal prepared for the implant was widened. Thus, following implant placement a circumferential gap occurred between the bone tissue and the implant surface that was between 1 and 1.25 mm wide. In each side of the mandible two implants with a turned surface and two implants with a rough surface were installed. The implants in the right side were fully submerged, while a non-submerged technique was applied in the left side. The animals were sacrificed 4 months later, block biopsies of each implant site were dissected and ground as well as paraffin sections were prepared.
  
  
  RESULTS
  The marginal defects around rough surface implants exhibited after 4 months of healing substantial bone fill and a high degree of osseointegration following either the submerged or the non-submerged installation technique. Healing at turned implants was characterized by incomplete bone fill and the presence of a connective tissue zone between the implant and the newly formed bone. The distance between the implant margin (M) and the most coronal level of bone-to-implant contact (B) at implants with a rough surface was 0.84+/-0.37 mm at submerged and 0.90+/-0.39 mm at non-submerged sites. The distance M-B at implants with a turned surface was 3.39+/-0.52 mm at submerged and 3.23+/-0.68 mm at non-submerged sites. The differences between the rough and turned implants regarding the length of distance M-B were statistically significant (paired t-test).
  
  
  CONCLUSIONS
  Osseointegration at implants placed in sites with marginal defects is influenced by the surface characteristics of the implant.
authors.affiliation: Department of Periodontology, Institute of Odontology, Sahlgrenska Academy at Göteborg University, Göteborg, Sweden. daniele.botticelli@odontologi.gu.se
authors.forename: Daniele
authors.initials: D
authors.lastname: Botticelli
authors.forename: Tord
authors.initials: T
authors.lastname: Berglundh
authors.forename: Leif G
authors.initials: LG
authors.lastname: Persson
authors.forename: Jan
authors.initials: J
authors.lastname: Lindhe
mesh_terms: D016301:Alveolar Bone Loss / Q000209:etiology*; D000818:Animals; D045662:Dental Etching; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants / Q000009:adverse effects; D003775:Dental Polishing; D017267:Dental Prosthesis Design / Q000009:adverse effects; D004285:Dogs; D008334:Mandible; D016348:Osseointegration; D013499:Surface Properties
chemical_list: D015921:Dental Implants