Objectives: Biofilms contamination of implant surfaces are part of the aetiology of peri-implantitis, and different surface decontamination techniques have been proposed as anti-infective therapy. However, no single intervention has been found to be superior. The focus of the present study was to explore the microbial ecology of the peri-implantitis microcosm, and to develop novel surface decontamination methods. Methods: Microcosm biofilms were grown for 30 days in a constant depth film fermenter (CDFF) on SLA andmTi discs, under standardised parameters associated with peri-implantitis. The discs were randomly allocated to three test groups (T1, T2, T3), and two control groups, one consisting of discs with undisturbed peri-implantitis microcosm biofilms (MC) and one with sterile discs (SC). The test group T1 underwent mechanical cleaning with a TiBrushTM (TiB); T2 underwent a combination of TiB and photodynamic therapy (PDT); and T3 underwent a combination of TiB and 0.2% chlorhexidine gluconate/1% sodium hypochlorate (CA). The biofilms were visualised under confocal laser scanning microscopy and surface chemistry was evaluated by scanning electron microscopy with energy dispersive x-ray analysis (SEM/EDX) and X-ray photoelectron spectroscopy (XPS). The bacterial composition of the biofilms was studied before and after disinfection by next-generation sequencing (NGS) of 16S rRNA gene amplicons (MiSeq). Cytocompatibility testing was carried out using AdB Serotech and endotoxin testing bacterial by Kinetic-QCL. Image J and CasaXPS were used for image analysis. Results: The CDFF peri-implantitis model presented here favoured the growth of higher proportions of Klebsiella, Prevotella, Parvimonas, Porphyromonadaceae (family), Actinomyces, Fusobacterium, Enterobacteriaceae (family), Lachno anaerobaculum and Corynebacterium in in vitro peri-implantitis conditions. ISO-surface-volume rendering and analysis of the confocal biofilm stacks revealed the complex microstructure of the undisturbed MC. The physicochemical composition of titanium surfaces before and after decontamination was also investigated, as well as the biocompatibility effect when cultured with MG-63 cells. Elemental analysis disclosed surface alterations of the discs undergoing different treatments. Endotoxin was found in MC and all test groups. The highest levels were found in M surfaces (MC: 12,000 UI/mL). The core microbiome differed between M and SLA surfaces. Bacteria were observed in all groups after disinfection. Streptococcus were present in all SLA- and M-treated samples. Overall, M surfaces were contaminated by Prevotella, Parvimonas, Klebsiella and Neisseria in the highest proportions. Conclusion: The CDFF is useful for modelling microbial shifts associated with peri-implantitis pathogen communities. It seems that the titanium substrata plays only a minor role in the development of mature biofilms. Our data suggest that no treatment modality hindered biocompatibility of the titanium surface. The bacteria were mainly composed of gram-negative species and Streptococcus, which prevailed after chemical and mechanical therapy and LPS was found in all experimental groups. Collectively, these results suggest that a successful treatment for peri-implantitis should be holistic, eliminating live bacteria and bacterial virulence factors, and take account of alterations in the titanium surface. The state of the titanium oxide layer following disinfection and host interactions biofilms warrant further investigation.

Outline: - Presentation of clinical findings - Explanations Er:YAG laser/fibre tip/power settings - Treatment - Postoperative management List of materials: Er:YAG laser device (KEY 3®, KaVo, Biberach, Germany) Laser handpiece (2061, KaVo, Biberach, Germany) Cone-shaped glass fibre tip Safety goggles Periodontal probe (PCP12, Hu-Friedy Co., Chicago, Illinois, USA)

Outline: - Patient presentation - Preparing the implant bed, implant placement, checking implant positions - Securing the insertion posts to the index for fabrication of the cast - Suturing details - Delivery of the adapted long-term provisional - Fabricating the cast and the gingival mask, transferring the pontic emergence profiles to the gingival mask, mask adaptation - The master cast under the strip scanner with scan bodies on the laboratory analogs - CAD crown design and virtual anatomic shaping - CAM fabrication of a zirconia abutment - Adhesively connecting the zirconia abutment to the titanium base - Reentry, split-thickness flap, vestibuloplasty, connecting the zirconia abutments to the implants - Mucosal graft to restore a soft-tissue defect - Intraoral impression of the abutments - Fabricating the definitive lithium disilicate crowns: virtual crown design; CAM milling, characterization of the crowns - Delivery, final adjustments, presentation of the treatment outcome