Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 10 4 2013 07 15 388 92 Amir Reza Rokn Associate Professor, Dental Implant Research Center, Department of Periodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran. Neda Sajedinejad Postgraduate Student of Periodontics. Tehran University of Medical Sciences, Tehran, Iran. Hosnieh Yousefyfakhr Postgraduate Student of Periodontics. Tehran University of Medical Sciences, Tehran, Iran. Samare Badri General Dentist, Private Practice, Tehran University of Medical Sciences, Tehran, Iran. 2015 10 16 Pre-implant disease is an inflammatory process that affects the surrounding tissues of a functional osseointegrated implant. It is usually the result of a disequilibrium between the micro-flora and the defense system. This case reports a 57-year-old man with unusual bone loss around dental implants. This was an unusual case of peri-implantitis that occurred only in the implants on one side of the mouth although they were all unloaded implants. https://fid.tums.ac.ir/index.php/fid/article/view/623 https://fid.tums.ac.ir/index.php/fid/article/download/623/598