Evaluation of Late Implant Placement in Vertically Regenerated Sites: A Systematic Review

Few studies with long-term follow-up show evidence of implants placed late in vertically regenerated sites. This has not allowed for generalizing about the prognosis and outcome of implants in these conditions. The objective was to evaluate the available scientific literature on the behavior of late-placed dental implants in vertically regenerated sites on three primary clinical outcomes: survival rate, marginal bone loss, and complications. A systematic search was performed in MEDLINE through Pubmed, Ebsco, Cochrane and Lilacs. Cohort studies (CTs) and controlled clinical trials (RCTs) conducted in humans, with a follow-up of ≥ 1 year, published between 2008 and 2021, were included. The data extraction process was also independent in a matrix for the variables of interest: type of surgery, technique, follow-up time, number of implants, number of patients, implant placement, prosthetic load, type of graft, and type of membrane complications. Of 3229 initial records, after deduplication and screening, 6 studies fully met the selection criteria. The included articles added 442 late implants to vertical bone regeneration in 178 patients. There was a loss of 14 implants (3.16%), overall survival was 96.8%, overall mean bone loss was 0.95 mm in a follow-up time of 1 to 10 years, and the most frequent complication was post-infection. With a 10-year follow-up, late implants placed in vertically regenerated sites have a survival rate (of 96.8%) like those placed in native bone or simultaneous to regeneration, with an average marginal bone loss of 0.98 mm. The most common complication is infection.