Surgical techniques used in the rehabilitation of partially edentulous patients with atrophic posterior mandibles: A systematic review and meta-analysis of randomized controlled clinical trials

Purpose Given the lack of general consensus in the literature regarding the best method to rehabilitate partially edentulous patients with extended atrophic edentulous sites in the posterior zone of the mandible, and with a residual ridge height less than 8 mm (with or without bone augmentation procedures), the aim of this systematic review was to analyze all the relevant randomized clinical trials (RCT), and, by means of a meta-analysis of the collected data, draw some conclusions regarding the best available treatments for the rehabilitation of posterior edentulism in partially dentate mandible. Materials and methods An electronic search was conducted in the MEDLINE and Cochrane Oral Health Group databases for studies published between January 2000 and September 2015 with the use of relevant keywords and hand-searching. All identified publications were screened by the authors according to the Cochrane Data Collection Form for Intervention Reviews. Collected outcomes such as biological complications, vertical ridge changes, implant and prosthetic failure were studied by subgroups analyses. Results An initial search yielded 81 potential articles, of which 12 studies were chosen for inclusion. Short implants seemed to be effective in limiting incidence of the biological complications (RR: 2.822; 95% CI: 1.809–4.403; p < 0.0001) and degree of ridge height reduction (difference in means of 0.052 mm; 95% CI: 0.026–0.079 mm; p < 0.0001) when compared with long implants placed in augmented bone. Implants placed in augmented areas with the use of onlay block grafts seemed to behave worse than implants placed in the augmented sites regardless of the augmentation procedures. However, this difference did not reach statistical significance. Conclusion Findings from subgroup analyses revealed that (1) short implants placed in the posterior atrophic areas of partially edentulous mandibles were associated with superior outcomes compared with long implants in augmented bone, such as lower rate of biological complications and of peri-implant bone loss; whereas (2), there was no evidence that onlay augmentation was inferior to any of the other augmentation techniques employed.