Treatment of experimental peri-implantitis lesions

The main objective of the present series of experiments was to study healing after treatment of experimental peri-implantitis lesions. The dog model was used. In order to establish recipient sites for implants in the mandible, the premolars and 1st molars were extracted. After a proper healing period, dental implants were installed. Standard and specially designed "test fixtures" of the Brånemark system® (Nobel Biocare AB, Göteborg, Sweden) and implants of the ITI Dental system® designed with turned and SLA surfaces (Straumann AG, Waldenburg, Switzerland) were used. Ligature induced breakdown of the peri-implant tissue was performed. The treatment protocol included systemic antibiotics (Metronidazole and Amoxicillin) and local therapy. The implants were cleaned with a detergent (delmopinol), an abrasive (pumice) or saline. The surgical procedure included excision of granulation tissue and installation of barrier membranes. The implants were left either submerged or non-submerged. After 4-7 months of healing block biopsies were harvested and prepared for light microscopy. It was observed that treatment of a peri-implantitis lesion, according to the above protocol resulted in the resolution of the peri-implantitis lesion and allowed for a substantial regrowth of bone within the defect. In animals receiving systemic antibiotics but no local therapy, the plaque associated lesion lingered and remained, in some sites, in contact with the adjacent bone tissue. Treatment of a peri-implantitis lesion, including a comprehensive systemic and local antimicrobial therapy and a submerged surgical technique resulted in the elimination of the inflammatory process in the peri-implant tissues and the establishment of a dense connective tissue capsule in direct contact with the previously exposed surface of the implant. When a new (pristine) implant part was introduced in the bone defect, new bone was frequently laid down on this surface. Treatment of a peri-implantitis lesion adjacent to an implant with a SLA surface, including systemic antibiotics combined with local therapy resulted in a substantial re-osseointegration , i.e. de novo bone formation on the titanium surface