Management and prevention of retrograde peri-implant infection from retained root tips: two case reports.

Fracture of root tips in the maxillary premolar region is not an uncommon finding because of the high incidence of bifid and root dilacerations. Therefore, a retained root tip may serve as a nidus of infection when a dental implant is placed. The likely result is the development of an implant periapical lesion. This case report shows the successful management of a rapidly developing implant periapical lesion caused by an undetected retained root tip. Initially, systemic antibiotics failed to subdue the infection. A retained root fragment was retrieved surgically, together with the implant, and a new wide-body implant was engaged with DFDBA mixed with tetracycline. A 5-month follow-up showed increased radiographic density, and clinical reentry revealed the formation of bone with a hard consistency. The second case demonstrates the management of a retained root tip via a guided bone regeneration technique when it is detected prior to or during implant placement. Finally, a systematic therapeutic approach is proposed based on 17 case reports on implant periapical lesion management.