Clinical Performance of Narrow-diameter Implants (NDIs) Supporting Fixed Prostheses in Stress-bearing Posterior Jaws: A Systematic Review

Abstract: Objectives: Narrow-diameter implants (NDIs) may serve as a feasible treatment alternative for the rehabilitation of specific cases. The aim of this review article was to assess the clinical outcomes of restoring stress-bearing posterior edentulous ridges with NDIs. Materials and Methods: An electronic search was conducted in MEDLINE/PubMed and Cochrane Library databases and enriched by hand search. Prospective and retrospective clinical studies, from January 2000 to November 2021, with at least 10 patients and a follow-up period of at least 1-year after functional loading, were included. Marginal bone level (MBL) and implant survival/success rate were set as primary outcome variables. Results: From the initially identified 2,401 articles, 17 clinical studies fulfilled the inclusion criteria and were included. Of the selected studies, mean MBL after loading was within 2 mm at different time intervals up to 10 years. Recorded implant survival rate was 92.6-100%, 95.3-100%, 95.3-100%, and 95.1-97.9% after 1-, 3-, 5-, and 10-year, respectively, while success rate was 92.6-100%, 95-100%, and 95% at 1, 3, and 10 years. Biological and prosthetic complications were observed. Conclusions: Within the limitation of the present study, it could be concluded that the use of NDIs for rehabilitation of posterior jaws is a viable treatment alternative, with comparable MBL and implant survival/success rate to standard-diameter implants (SDIs).