Experimental periodontitis and peri-implantitis in dogs

Aim To analyze the tissue reactions following ligature removal in experimental periodontitis and peri‐implantitis in dogs. Material and methods Four implants with similar geometry and with two different surface characteristics (turned/TiUnite Nobel BioCare AB, Göteborg) were placed pair‐wise in a randomized order in the right side of the mandible 3 months after tooth extraction in 5 dogs. Experimental peri‐implantitis and periodontitis were initiated 3 months later by ligature placement around implants and mandibular premolars and plaque formation. The ligatures were removed after 10 weeks, and block biopsies were obtained and prepared for histological analysis 6 months later. Results It was demonstrated that the amount of bone loss that occurred during the period following ligature removal was significantly larger at implants with a modified surface than at implants with a turned surface and at teeth. The histological analysis revealed that peri‐implantitis sites exhibited inflammatory cell infiltrates that were larger, extended closer to the bone crest and contained larger proportions of neutrophil granulocytes and osteoclasts than in periodontitis. Conclusion It is suggested that lesions produced in experimental periodontitis, and peri‐implantitis are different and that implant surface characteristics influence the inflammatory process in experimental peri‐implantitis and the magnitude of the resulting tissue destruction.