Inflammatory reactions in the gingiva and the periimplant mucosa

The purpose of the present series of investigations was to study the tissue response to plaque formation at teeth and implants as well as local mechanisms involved in the regulation of the inflammatory process.The reaction of the periimplant mucosa (PiM) to long-standing plaque accumulation on implant abutments with different surface roughness was analysed in the dog model (Study I). The host response of the gingiva and PiM to de novo plaque formation was investigated in 12 human subjects (experimental gingivitis model). The expression of leukocyte adhesion molecules (CAMs) on endothelial cells in the alveolar ridge mucosa, the gingiva and PiM was also examined (Study II and III). 15 patients with severe chronic periodontitis were treated with resective (gingivectomy, GV) and non-resective periodontal therapy (open flap debridement, OFD) in a split-mouth design. The soft tissue healing was investigated after 6 months (Study IV). The host response to plaque formation at sites treated by resective or non-resective means was subsequently analysed (Study V).It was demonstrated that:- The surface characteristics of implant abutments had no obvious influence on the inflammatory cell lesions (ICT) formed in PiM of the dog (Study I).- De novo plaque formation around teeth and implants induced an inflammatory response in the soft tissue characterized by increased proportions of T- and B-cells in the lesion. The increase in size of the ICT and in the cell densities tended to be more pronounced in the gingiva than in PiM (Study II).- The densities of activated CAMs and the proportion of leukocytes were larger in clinically healthy gingiva and PiM than in the alveolar ridge mucosa (Study III).- Surgical therapy (GV sites) resulted in pristine gingival units that contained smaller lesions with lower densities of immunocompetent cells than the treatment that included non-resective means (Study IV).- The host response that occurred in the OFD treated sites was more pronounced than the reaction that under similar conditions took place in gingival units formed after resective therapy. The local site-specific environment may influence the tissue response to microbial challenge (Study V)