In recent years, various risk factors and treatments for peri-implantitis, one of the most common complications after implant treatment, have been studied. Peri-implant mucositis or periimplantitis is defined as infection of the plaque biofilm according to the new classification of EFP and AAP published in 2018. In order to prevent the development of peri-implant diseases, we would like to compare natural teeth and peri-implant tissues, especially focusing on peri-implant soft tissues, and consider methods to prevent these diseases that can be applied today.