Prevention and treatment of experimental peri-implantitis

Abstract: Peri-implantitis is a plaque-associated pathological condition occurring in tissues around dental implants. It is characterized by inflammation in the peri-implant mucosa and progressive loss of supporting bone. The aims of the present series of studies were to (a) analyze the effect of plaque-formation on implant abut-ments with an antibacterial coating, (b) evaluate the effect of surgical treatment of experimental peri-implantitis using different decontamination methods, (c) evaluate the effect of the use of bone substitute materials on soft and hard tissue healing following reconstructive surgical therapy and (d) evaluate the accuracy of bone level assessments using either cone beam computed tomography, intra-oral periapical radiographs or histology. In Study I, plaque formed on implant abutments with an antimicrobial coating for 6 months. Data from radiological, microbiological and histological examinations were analyzed. In study II, III and IV, differ-ent surgical treatment protocols of experimental peri-implantitis were applied to implants with different surface characteristics. Radiographs were obtained to longitudinally evaluate disease progression and treatment outcome and block biopsies were obtained and prepared for histological analysis. In study IV, cone beam computed tomography was obtained following reconstructive treatment of experimental peri-implantitis. Implant abutments with an antibacterial coating failed to prevent biofilm formation and did not influence the inflammatory response in the adjacent peri-implant mucosa (Study I). Disease resolution of experi-mental peri-implantitis occurred after surgical therapy using different methods for implant surface decon-tamination (Study II and III). Healing following surgical treatment of experimental peri-implantitis was superior around implants with a smooth surface than at implants with rougher surfaces. (Study II and III). Defect fill and re-osseointegration following reconstructive peri-implantitis surgery occurred at 23 out of 24 implants with a smooth surface and at 13 out of 24 implants with a moderately rough surface. The additional effect of using bone substitute materials during surgery was small (Study III). Significant corre-lations were observed between assessments of marginal bone levels using cone beam computed tomogra-phy, periapical radiographs or histology. Measurements in periapical radiographs consistently resulted in an overestimation of the bone level of about 0.3 mm (Study IV).