What is the survival rate of dental implants placed at sites of failed implants?

Data sources OVID Medline, EMBASE, and SCOPUS databases from 1991 till 2018. Manual search of the reference lists of review and related articles.Study selection Prospective and retrospective clinical studies reporting survival rate of dental implants placed at sites of failed implants. The selection was limited to studies that comprised at least 15 partially edentulous patients and 20 dental implants. Only papers published in English language were included.Data extraction and synthesis The first and second authors independently reviewed the literature and agreed on abstracted data. The Newcastle-Ottawa scale for cohort studies was used to assess quality and risk of bias in the selected studies. The primary outcome was the survival rate of replacement dental implants. The survival rate of replacement implants in relation to surface design (smooth versus rough) and implant sites (anterior versus posterior) were considered as secondary outcomes.Results The mean survival rate of replacement dental implants was 86.3%. The follow-up period ranged from less than one year to more than five years. Rough-surfaced implants showed a significantly higher survival rate compared to smooth-surfaced implants (90% versus 68.7%). It was not possible to assess the impact of patient- or treatment-related factors on survival rate of replacement dental implants.Conclusions Replacement dental implants have a high survival rate but it is less than that for initial implant placement. In retreatment, a higher survival rate is associated with rough-surfaced implants. It seems that initial implant failures are mostly related to modifiable risk factors.