Analysis of undisturbed plaque formation, composition, and growth around dental implants

Potential participants will be identified and screened by the treating specialist periodontists (Axel Spahr and Jessica O’Neill) through routine assessment of hospital patients that have been referred for implant treatment. These patients will be screened for suitability for implant treatment, as well as eligibility for this research study. Patients that fulfil the inclusion criteria will be invited to participate in the research. A personal (face-to-face) invitation with a periodontics registrar (Judd Sher) will then be offered to interested patients where full-details and information about the study will be disclosed, as well as answering of any questions posed by the participants. Straumann bone-level implants will be placed in a 90 minute appointment as per the manufacturers instructions by a registered periodontist (Axel Spahr and Jessica O’Neill) or periodontics registrar (Judd Sher) and allowed to osseointegrate for 12-weeks. An impression will be taken for study casts once soft-tissue healing following second-stage surgery is completed, where an Implant Supported Biofilm Chamber (ISBC) and custom abutment will be fabricated. The ISBC will be fabricated using CAD-CAM and will be designed in a way where discs can be inserted into a chamber which is easily coverable with composite resin. The ISBC will be 3D-printed with a Formlabs Form 2/3B 3D-printer using a biocompatible light-cured dental resin (Dental LT Clear Resin, Formlabs) that is TGA- approved for dental applications such as occlusal splints, permanent and temporary restorations, and orthodontic appliances. Technical and safety data can be found on the manufacturer’s website: https://dental.formlabs.com/ The chamber will also consist of a channel that is directed and opens into the sulcular (interproximal) region, with to aim to allow gingival crevicular fluid (GCF), saliva and substrate to flow into the chamber. A zirconia disc with a standardised roughness will be milled and mounted in the ISBC. All ISBCs and discs will be disinfected in a 3% sodium hypochlorite solution for 10-minutes, rinsed in distilled water, and autoclaved before use. A final implant-supported prosthesis or restoration will be fabricated and inserted following completion of data collection. The patient will receive a full mouth clean (mechanical removal of plaque and calculus) with ultrasonic and airflow prior to start of each time point. Oral hygiene instructions (OHI) will also be given to the patient: toothbrushing technique and interdental care. Two discs will be inserted into the ISBC at each time point. Biofilm will be allowed to grow, and the ceramic disk will be removed atraumatically for microbiological analysis and replaced with a new disc at 1-hour, 24-hours, 2-days, 4-days, 7-days, and 14-days. Each disk insertion/removal visit will take 30 minutes. A total of 12 discs will be fabricated per participant (2 disks will be inserted into the ISBC for each timepoint). At each time point following disc removal, one disk will be used to analyse biofilm viability with confocal laser scanning microscopy (CLSM) while the other will be used to analyse bacterial composition with next generation sequencing.