title: Analysis of inflammatory periimplant lesions during a 12-week period of undisturbed plaque accumulation--a comparison between flapless and flap surgery in the mini-pig.
abstract: This study's aim was to clarify the influence of soft tissue management on the development of periimplant infection. Four weeks after removal of all maxillary premolars in 12 mini-pigs, four BEGO Semados RI implants were inserted in each maxillary quadrant. Employing a split-mouth design, one quadrant was randomized to flapless insertion while the contralateral side was chosen for flap surgery. Following 1, 2, 4 and 12 weeks of transmucosal implant, healing biopsies were retrieved from the periimplant soft tissue and subjected to further analysis. Histomorphometrically, a significant reduction of transmigration of polymorphonuclear neutrophils (week 1, p = 0.007; week 2, p = 0.021; week 4, p = 0.023; week 12, p = 0.013) as well as the density of the subepithelial inflammatory infiltrates (week 1, p = 0.007; week 2, p = 0.046; week 4, p = 0.003; week 12, p = 0.032) was verified following flapless surgery. Quantification of inducible nitric oxide synthase showed significantly reduced expression in the flapless group 2 (p = 0.027), 4 (p = 0.005) and 12 (p = 0.004) weeks post-insertion. Analysis of CD31 and collagen I immunostained sections revealed more regular capillary distribution as well as higher vessel and collagen density in the flapless group. The data of the present study indicate that flapless placement reduces the incidence of inflammatory periimplant soft tissue lesions during a 12-week period. Considering the beneficial effects of flapless placement on early soft tissue healing and stability, the technique might be preferred in case of an uncomplicated locoregional anatomy with sufficient hard and soft tissue. However, this positive effect might disappear after manipulation of the implant and soft tissue during impression taking or try in of the prosthodontic supraconstruction.
authors.affiliation: Department of Oral and Maxillofacial Surgery/Plastic Surgery, School of Medicine, University of Jena, Jena, Germany. Cornelia.Mueller1@med.uni-jena.de
authors.forename: Cornelia K
authors.initials: CK
authors.lastname: Mueller
authors.forename: Michael
authors.initials: M
authors.lastname: Thorwarth
authors.forename: Stefan
authors.initials: S
authors.lastname: Schultze-Mosgau
mesh_terms: D000818:Animals; D002196:Capillaries / Q000473:pathology; D002452:Cell Count; D024042:Collagen Type I / Q000032:analysis; D003238:Connective Tissue / Q000098:blood supply / Q000473:pathology; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D003773:Dental Plaque / Q000150:complications*; D004846:Epithelial Attachment / Q000473:pathology; D005260:Female; D008437:Maxilla / Q000601:surgery; D020556:Neutrophil Infiltration / Q000502:physiology; D009504:Neutrophils / Q000473:pathology; D052247:Nitric Oxide Synthase Type II / Q000032:analysis; D010027:Osteotomy / Q000379:methods; D057873:Peri-Implantitis / Q000209:etiology* / Q000473:pathology; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000032:analysis; D011677:Punctures / Q000379:methods; D011897:Random Allocation; D013524:Surgical Flaps; D013552:Swine; D013556:Swine, Miniature; D013997:Time Factors; D014945:Wound Healing / Q000502:physiology
chemical_list: D024042:Collagen Type I; D015921:Dental Implants; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D052247:Nitric Oxide Synthase Type II