The leakage of microorganisms and fluids to the inner parts of the implants is considerably increased by load application, which generates micro-movements and interfacial gaps. (Khraisat et al., 2006). Bacterial species harboring the internal surfaces of the implants and components is not surprising, since the size of oral bacterial species ranges in average from 1.1 to 1.5 μm in length and 2 to 6 μm in diameter. Smaller species like spirochetes (diameter of 0.1 to 0.5 μm) may also be found in the oral microbiota. (Jansen et al., 1997).

Micro gaps between implant and abutment are generally less than 10 um. Given access to the microgap, bacteria can easily penetrate even through the tightest implant-abutment fittings. Biofilms and bacterial colonization of dental implants. According to Quirynen et al. (2002), gaps in the implant-abutment interface may act as a trap for bacteria, favoring the development of biofilm with varying composition and impact on periodontal tissues. AA, T forsythia and P gingivalis, many times present in these biofilms, are pathogens intimately related to the development and maintenance of periodontitis and peri-implantitis. Considering the increased use of dental implants and recognizing the impact of bacterial leakage along the implant-abutment interface on the health of peri-implant tissues this study was planned.

ABOUT METAGENOMICS-The next culture-independent game changer

Recently, metagenomics was defined as "the application of modern genomics techniques to the study of communities of microbial organisms directly in their natural environments, bypassing the need for isolation and lab cultivation of individual species".