Short versus standard implants associated with sinus floor elevation: An umbrella review of meta-analyses of multiple outcomes

Statement of problem. Bone loss in the edentulous posterior maxilla complicates dental implant placement. In spite of the evidence available, there is continued uncertainty about the benefit of short implants for different outcomes. Purpose. The purpose of this review was to evaluate the existing evidence for short and standard implants in association with sinus floor elevation regarding implant survival, marginal bone loss, and complications by using an umbrella review of the evidence across meta-analysis of interventional studies. Material and methods. Medline, Scopus, and Cochrane Library were searched to identify systematic reviews and meta-analyses comparing short implants and standard implants associated with sinus floor elevation. Data extraction and methodological quality (AMSTAR-2) was assessed by 2 authors independently. Outcomes were categorized and tabulated to assess effectiveness. Qualitative data were analyzed using thematic synthesis. The certainty of the evidence was evaluated with the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Results. From 2011 studies, 7 systematic reviews (66 studies) were included as per the eligibility criteria. There was no statistically significant difference between groups for implant survival (risk ratio=1.08; P=.79), and the qualitative analysis did not show differences for prosthetic outcomes. Standard implants were associated with fewer prosthetic complications in the quantitative analysis (risk ratio=3.27; P<.01), but no difference was found between the treatments in the qualitative analysis. Short implants showed reduced marginal bone loss (0.98 +/- 0.12 mm; mean difference=-0.22; P<.01) and better biologic outcomes (risk ratio=0.16; P<.01). Patient satisfaction was similar for both groups, whereas costs and time for the procedure favored short implants. The quality of the evidence was graded as "critically low" (57.1% of the reviews) and "low." There was a high certainty of evidence for implant survival, whereas marginal bone loss and complications had moderate certainty. Conclusions. Short implants had a better or equal performance compared with standard implants for all outcomes assessed. However, assumptions were based on reviews with low or critically low quality of the evidence, suggesting the development of high-quality systematic reviews in this field. (J Prosthet Dent 2021;126:503-11)