What Is the Most Effective Rehabilitation Method for Posterior Maxillas With 4 to 8 mm of Residual Alveolar Bone Height Below the Maxillary Sinus With Implant-Supported Prostheses? A Frequentist Network Meta-Analysis.

PURPOSE: The most effective rehabilitation method for patients with edentulous posterior maxillas with an intermediate (4 to 8 mm) residual bone height (RBH) below the maxillary sinus is unclear. Evidence derived from conventional meta-analysis is limited because of the lack of head-to-head studies. This network meta-analysis (NMA) was performed to identify the most effective method to treat patients with intermediate posterior RBH.

MATERIALS AND METHODS: An NMA of randomized controlled clinical trials (RCTs) was conducted to assess various rehabilitation methods using implant-supported prostheses for patients with intermediate posterior maxillary RBH (4 to 8 mm). Publications from 1970 through March 2018 in 3 major databases were searched. Parallel and split-mouth RCTs that reported the outcomes of interest with follow-up of at least 6 months from initial loading were included. Predictor variables were short implants (SIs; ≤8 mm) alone, SIs in conjunction with osteotome sinus floor elevation (OSFE) with or without bone grafting, long implants (LIs) in conjunction with OSFE with and without bone grafting, and LIs combined with lateral sinus floor elevation (LSFE) with bone grafting. Outcome variables were implant and prosthesis failure rates, marginal bone loss, and complications. Frequentist NMA was performed using STATA software.

RESULTS: Twenty RCTs involving 770 patients with intermediate posterior maxillary RBH and 837 concerned maxillary sinuses who received 1,486 implants using any of the 4 rehabilitation methods were included. There were no statistically significant differences among the 4 groups for implant and prosthesis failure rates and marginal bone loss at follow-up (range, 6 months to 5 years after loading). There was a marked decrease in complications for SIs alone compared with LIs combined with LSFE. For implant and prosthesis survival rates, SIs in conjunction with OSFE with or without bone grafting ranked first as the most effective option (77.1%) followed by LIs plus OSFE with or without bone grafting (62%), LIs plus LSFE with bone grafting (43.9%), and SIs alone (24.8%).

CONCLUSION: There is moderate-quality evidence derived from this NMA showing that OSFE combined with SI or LI placement with or without bone grafting or SI placement alone is superior to LI placement combined with LSFE and bone grafting when used for patients with intermediate maxillary RBH (4 to 8 mm). Furthermore, the results of this study show that LSFE for patients with intermediate RBH is not a suitable treatment option because of unjustified high cost and rate of complications.