Prevalence and treatment of retrograde peri-implantitis: a retrospective cohort study covering a 20-year period.

Bacteria from teeth with failed endodontic treatment or residual lesions might be reactivated by drilling for implant osteotomy, with subsequent colonization of the implant apex and possible failure before prosthetic loading. Therefore, it might be recommended to take a periapical x-ray at implant placement and after 6-8 weeks in order to intercept RPI before prostheses delivery.