title: Spontaneous progression of ligature induced peri-implantitis at implants with different surface roughness: an experimental study in dogs.
abstract: BACKGROUND
  Peri-implantitis is associated with the presence of submarginal plaque, soft-tissue inflammation and advanced breakdown of the supporting bone. The progression of peri-implantitis following varying periods of continuing plaque accumulation has been studied in animal models.
  
  
  OBJECTIVE
  The aim of the current experiment was to study the progression of peri-implantitis around implants with different surface roughness.
  
  
  METHODS
  In five beagle dogs, three implants with either a sandblasted acid-etched surface (SLA) or a polished surface (P) were installed bilaterally in the edentulous premolar regions. After 3 months on a plaque control regimen, experimental peri-implantitis was induced by ligature placement and plaque accumulation was allowed to progress until about 40% of the height of the supporting bone had been lost. After this 4-month period, ligatures were removed and plaque accumulation was continued for an additional 5 months. Radiographs of all implant sites were obtained before and after 'active' experimental peri-implantitis as well as at the end of the experiment. Biopsies were harvested and the tissue samples were prepared for light microscopy. The sections were used for histometric and morphometric examinations.
  
  
  RESULTS
  The radiographic examinations indicated that similar amounts of bone loss occurred at SLA and P sites during the active breakdown period, while the progression of bone loss was larger at SLA than at polished sites following ligature removal. The histological examination revealed that both bone loss and the size of the inflammatory lesion in the connective tissue were larger in SLA than in polished implant sites. The area of plaque was also larger at implants with an SLA surface than at implants with a polished surface.
  
  
  CONCLUSIONS
  It is suggested that the progression of peri-implantitis, if left untreated, is more pronounced at implants with a moderately rough surface than at implants with a polished surface.
authors.affiliation: Department of Periodontology, Göteborg University, Göteborg, Sweden. berglundh@odontologi.gu.se
authors.forename: T
authors.initials: T
authors.lastname: Berglundh
authors.forename: K
authors.initials: K
authors.lastname: Gotfredsen
authors.forename: N U
authors.initials: NU
authors.lastname: Zitzmann
authors.forename: N P
authors.initials: NP
authors.lastname: Lang
authors.forename: J
authors.initials: J
authors.lastname: Lindhe
mesh_terms: D000134:Acid Etching, Dental; D016301:Alveolar Bone Loss / Q000473:pathology / Q000503:physiopathology; D000818:Animals; D001641:Bicuspid; D001706:Biopsy; D003238:Connective Tissue / Q000473:pathology; D045662:Dental Etching; D015921:Dental Implants; D003764:Dental Materials / Q000737:chemistry; D003773:Dental Plaque / Q000517:prevention & control; D003775:Dental Polishing; D017267:Dental Prosthesis Design; D004195:Disease Models, Animal; D018450:Disease Progression; D004285:Dogs; D007576:Jaw, Edentulous, Partially / Q000601:surgery; D010518:Periodontitis / Q000473:pathology / Q000503:physiopathology*; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry
chemical_list: D015921:Dental Implants; D003764:Dental Materials; D014025:Titanium