Root-analog dental implants: A systematic review of the available clinical evidence

Root-analog implants (RAIs) aim to replicate natural tooth root morphology, potentially enhancing the outcomes of immediate implant placement. However, clinical evidence on their survival, success, and long-term reliability is limited and varied.

This systematic review aimed to evaluate the clinical survival and success of RAIs fabricated using different biomaterials and digital fabrication methods.

A systematic search of the PubMed, Scopus, Web of Science, and Cochrane databases was conducted by following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Clinical trials, case series, and clinical reports on human RAIs were included. The risk of bias was assessed using the Cochrane Risk of Bias Tool (RoB 2), ROBINS-I, Newcastle-Ottawa Scale (NOS), and JBI tools. Primary outcomes were survival and success rates; secondary outcomes included marginal bone loss (MBL), esthetics, prosthetic performance, and patient satisfaction.

Twenty-eight studies (432 RAIs) were included. RAIs were made from titanium, zirconia, or hybrid titanium-zirconia materials using CNC milling, selective laser melting (SLM), or direct laser metal sintering (DLMS). Most studies reported survival rates ranging from 71% to 100% and success rates from 64.5% to 100%. Titanium and hybrid RAIs were more predictable than zirconia, which showed higher failure and fracture rates. RAIs demonstrated favorable esthetic and soft-tissue outcomes, as well as high patient satisfaction. Evidence was limited by small cohorts, heterogeneous protocols, and scarce long-term follow-up.

RAIs show promising short-term survival, stability, and esthetics, particularly with implants using titanium or combined titanium-zirconia materials. However, variability in outcomes highlights the need for well-designed multicenter trials with larger cohorts and longer follow-up to confirm long-term clinical reliability.