Journal of Periodontology; Copyright 2017 DOI: 10.1902/jop.2017.170123 1 Microbiome and Microbial Biofilm Profiles of Peri-Implantitis: A Systematic Review Gloria Inés Lafaurie*, María Alejandra Sabogal*, Diana Marcela Castillo*, María Victoria Rincón † , Luz Amparo Gómez † , Yamil Augusto Lesmes † , and Leandro Chambrone* ‡§ *Unit of Basic Oral Investigations-UIBO, School of Dentistry, El Bosque University, Bogotá, Colombia. † School of Dentistry, El Bosque University, Bogotá, Colombia. ‡ School of Dentistry, Ibirapuera University, Sao Paulo, SP, Brazil. § Department of Periodontics, School of Dentistry, The University of Iowa, Iowa City, USA. Background: This systematic review assesses the microbiological profiles of peri-implantitis, periodontitis and healthy implants based on studies that evaluated microbial biofilms and entire microbiomes to establish their similarities and differences. Methods: The Medical Literature Analysis and Retrieval System Online, via PubMed, EMBASE (Excerpta Medica Database) and Cochrane Central Register of Controlled Trials (CENTRAL) were searched without language restrictions through July 30, 2016. Observational studies that evaluated the microbial profiles or entire microbiomes of peri-implantitis compared with healthy implants or periodontitis were considered eligible for inclusion. A descriptive summary was created to determine the quantity of data and inter-study variations. Results: Of the 126 potentially eligible articles, 26 were included in this study; 21 of these articles evaluated the microbiological profile of peri-implantitis vs. healthy implants or periodontitis using conventional microbiological techniques and five articles evaluated the entire microbiome using genomic sequencing. Teeth with periodontitis, healthy implants, or implants with peri-implantitis were colonized by periodontal microorganisms. Porphyromonas gingivalis and especially Prevotella intermedius/nigrescens were often identified at peri-implantitis sites. Peri-implantitis sites were also colonized by uncultivable asaccharolytic anaerobic gram-positive rods and anaerobic gram-negative rods, which were not frequently identified in teeth with periodontitis or healthy implants. Opportunistic microorganisms were not found very frequently in peri-implantitis sites. Conclusions: Peri-implantitis represents a heterogeneous mixed infection that includes periodontopathic microorganisms, uncultivable asaccharolytic anaerobic gram-positive rods and other uncultivable gram-negative rods and, rarely, opportunistic microorganisms such as enteric rods and Staphylococcus aureus. Sequencing methods that evaluate the entire microbiome improve the identification of microorganisms associated with peri-implantitis. KEY WORDS (MESH TERMS): chronic periodontitis; peri-implantitis; dental implants; microbiota; microbial genome; gram- positive rods. Edentulism remains a public health problem worldwide. 1 Dental implants have improved oral rehabilitation in partial and complete edentulous patients, and their survival is reported with high rates of success. 2 Nevertheless, an increase in peri-implantitis has been reported with frequencies ranging between 14 and 30%. 3 A history of periodontitis, 4 current smoking and diabetes are the most important risk factors associated with peri-implantitis. 5 However, the importance of dental biofilms in the etiology of peri-implantitis has been extensively studied as well. 6 Peri-implantitis is characterized by an inflammatory process around the implants that includes both soft tissue inflammation and progressive bone loss. 7 However, peri-implantitis is associated with changes in the crestal bone level in conjunction with bleeding on probing with or