Microbial Principles of Peri-Implant Infections

Oral diseases are the most prevalent noncommunicable diseases in humans and are mostly attributed to polymicrobial biofilms that form onto the hard and soft oral tissue surfaces. Every so often, osseointegrated dental implants are surgically installed in the oral cavity of patients that have undergone reconstructive dental treatments. Part of their metallic surfaces are also exposed to the microbe-rich environment of the oral cavity, and thus are prone to microbial colonization. In early stages, peri-implant microbial communities display high abundances of commensals species resembling those of healthy gingival sulci, albeit with lower diversity. As peri-implant tissues are structurally more susceptible to endogenous infections, any occurring microbial shifts can rapidly lead to peri-implant inflammation and jeopardize implant functionality. Therefore, a firm grasp of the biofilms that underpin the etiology of peri-implant diseases is central to improving prevention, diagnosis, and therapeutic strategies. This chapter summarizes knowledge of the underlying peri-implant ecology, focusing on the latest community profiling and meta-transcriptomics. Overall, the peri-implant niche is indeed a unique ecosystem, selective for the establishment of distinct microbial communities. Shifts from peri-implant health to disease are commensurate with an increase in the diversity of species and an enrichment of long-known and newly discovered periodontopathogens.