title: Histopathological comparison of the onset of peri-implantitis and periodontitis in rats.
abstract: OBJECTIVE
  There are a few experimental models that clearly describe the pathological differences in tissue destruction between periodontitis and peri-implantitis. We recently reported that the formation of immune complexes accelerates site-specific loss of attachment and alveolar bone resorption when an antigen is topically applied in the gingival sulcus of an immunized rat. We applied this model to the peri-implant tissues and compared peri-implant destruction to periodontitis without using a ligature.
  
  
  METHODS
  Twenty-five rats were used in this study and were divided into five groups. Implantation was performed immediately after extraction of right first molars in rats. The left first molars were left untreated to be examined as natural teeth. The immunized group consisted of rats that had received intraperitoneal lipopolysaccharide (LPS), whereas the nonimmunized group received only phosphate-buffered saline (PBS). The untreated baseline group received only implantation. After intraperitoneal booster injection, half of each group received topical application of LPS in the palatal gingival sulcus daily for 3 days. The other half of the groups received PBS. Histopathological and histometrical findings were observed with hematoxylin and eosin staining, collagen fibers were observed with Azan staining, and formation of immune complexes was immunohistologically evaluated by C1qB expression.
  
  
  RESULTS
  Peri-implant tissue destruction was greater in the immunized and LPS-applied groups than in the other groups. No periodontal destruction was observed. Formation of immune complexes was observed in the junctional epithelium and adjacent connective tissue in the immunized groups.
  
  
  CONCLUSIONS
  Antigen-induced peri-implant tissue destruction occurs faster than periodontal tissue destruction.
authors.affiliation: Unit of Translational Medicine, Course of Medicine, and Dental Sciences, Department of Periodontology, Nagasaki University Graduate School of Biomedical Science, Nagasaki, Japan.
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Takamori
authors.affiliation: Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan.
authors.forename: Ikiru
authors.initials: I
authors.lastname: Atsuta
authors.affiliation: Unit of Translational Medicine, Course of Medicine, and Dental Sciences, Department of Periodontology, Nagasaki University Graduate School of Biomedical Science, Nagasaki, Japan.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Nakamura
authors.affiliation: Department of Applied Prosthodontics, Unit of Translational Medicine, Course of Medicine, and Dental Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Sawase
authors.affiliation: Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Koyano
authors.affiliation: Unit of Translational Medicine, Course of Medicine, and Dental Sciences, Department of Periodontology, Nagasaki University Graduate School of Biomedical Science, Nagasaki, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Hara
mesh_terms: D000818:Animals; D004797:Enzyme-Linked Immunosorbent Assay; D007074:Immunoglobulin G / Q000097:blood; D007150:Immunohistochemistry; D008070:Lipopolysaccharides; D008297:Male; D008437:Maxilla / Q000601:surgery; D008963:Molar; D057873:Peri-Implantitis / Q000473:pathology*; D010518:Periodontitis / Q000473:pathology*; D051381:Rats; D011917:Rats, Inbred Lew
chemical_list: D007074:Immunoglobulin G; D008070:Lipopolysaccharides
keywords: bone implant interactions; periodontology; soft tissue-implant interactions