1. To investigate the transcriptomic profile of periodontitis and peri-implantitis. Patients with defined periodontitis, at two non-adjacent teeth and peri-implantitis at ≥ one implant in function of ≥ one year, will be included to investigate the gene expression profile in tissue affected by periodontitis and peri-implantitis. Subjects will undergo a full-mouth examination performed by a calibrated examiner, including assessment of caries, bone abnormalities and infections according to intraoral x-ray, plaque index and pocket probing depth, suppuration, bleeding on probing, alveolar bone loss, and the number of teeth. During surgical intervention, tissue biopsies (two specimens per site) will be collected by a periodontist from site with ongoing periodontitis and site from ongoing peri-implantitis. 2. To study the microbiome and biomarker profile associated with periodontitis and peri- implantitis. Patients with defined periodontitis, at two non-adjacent teeth and peri-implantitis at ≥ one implant in function of ≥ one year, will be included in this study to determine the bacteria composition, cytokine profile and inflammatory biomarkers profile. Subjects will undergo a full-mouth examination performed by a calibrated examiner, including assessment of caries, bone abnormalities and infections according to intraoral x-ray, plaque index and pocket probing depth, suppuration, bleeding on probing, alveolar bone loss, and number of teeth. Peri-implant crevicular fluid (PICF), gingival crevicular fluid (GCF), saliva and submucosal/subgingival plaque will be collected.The presence and composition of periodontal and peri-implant plaque samples are investigated.