Since the introduction of osseointegrated implant treatment, odontology, and in particular the area of prosthodontic replacement of lost teeth, has evolved in an unimaginable way, to the extent that the age-old idea of ?restitutio ad integrum? has almost become possible. Implant treatment has a high success rate that has been rated as high as 95 to 99%, according to different casuists, but there is another group of cases in which implants fail, and in fact it is hard to know the causes of such failures. The microbiological component plays an important role in encouraging and facilitating implant infection during implant placement, and also later when the implant is in function in the mouth, which is a septic medium. In this paper we will study infections in implantology, classified according to the treatment phase: Infection prior to the implant; Peri-surgical infection; Severe post-surgical infection; Peri-implant disease.