Changes in Microbial Status From Dentate, Edentulous and After Dental Implant Placement

The introduction of dental implants has significantly changed the treatment approach for prosthetic rehabilitation of partially and edentulous patients. In the last decades an increasing number of patients have received implants for the replacement of missing teeth. Although dental implants have proved to be a very predictable treatment option, in the long term they are susceptible to biologic complications that may lead to implant loss. In particular, two major peri-implants conditions have been described: peri-implant mucositis and peri-implantitis. Peri-implant mucositis is an inflammatory condition of the peri-implant tissue without bone loss and is considered reversible once the biofilm is removed; Peri-implantitis is an inflammatory condition that affect the bone support of the implant and if untreated may lead to implant loss. The major etiologic factors involved in Peri-implantitis are: history of periodontitis, poor plaque control, and poor patient compliance. The high susceptibility to biologic complication of implants placed in partially edentulous patients with history of periodontitis has been demonstrated in several studies. Multiple studies demonstrated periodontal pathogens can transfer from teeth to implants. However, it is unclear whether the same occurs on implants placed in edentulous subjects that have lost their dentition due to periodontitis. Previous investigations have shown a significant reduction but not the complete elimination of putative periodontal pathogens following full mouth extractions. Most of the studies on microbial population around teeth and implants are based on assessing the presence or absence of putative pathogens. Limited information is available regarding the whole microbiome shift from dentate to edentulous status and the changes occurring around the implant crevice after implants are placed. The use of 16S RNA pyrosequencing has been recently introduced to study the oral microbiome in health and disease. More recently shotgun metagenomic sequencing was introduced which allows evaluation of all the genes in a microbial community thereby revealing information on community composition and also community functional capacity. Shotgun sequencing also allows tracking of strains using single nucleotide variants or gene-content assessments, allowing assessment of longitudinal changes in colonization. The purpose of this investigation is to assess the oral microbiome changes in subjects with terminal dentition due to periodontitis over the entire treatment period, including the shift from dentate status to edentulous and finally post-implant.

Patients diagnosed with terminal dentition due to periodontitis with the intention to replace the dentition with implant-supported/retained restorations will be invited to participate.

Visit 1 - Screening visit to evaluate patient qualification for the study. Inclusion-Exclusion criteria. Qualifying patients will be enrolled and will receive a full mouth examination including an assessment of PD, clinical attachment level (CAL), BoP, and furcation involvement.

Visit 2 - Baseline microbial sampling and Full mouth extractions. Pool microbial sampling will be performed before teeth extractions. An immediate denture may be delivered at this time.

Visit 3 - Diagnostics for Implant Placement 3-4 months after teeth extraction. Diagnostic appointments may include multiple visits for diagnostics setup, Cone-beam computed tomography (CBCT), and provisional denture adjustments prior to implant placement.