Lateral sinus floor elevation without grafting materials. Individual- and aggregate-data meta-analysis

Abstract

Purpose: To perform a systematic review and individual- and aggregate-data meta-analysis of observational studies to determine the success rate of the lateral sinus floor elevation with simultaneous implant placement and without grafting materials.

Material and methods: We included prospective and retrospective observational studies analyzing survival rate of implants in patients who underwent graftless lateral sinus floor elevation. Secondary outcomes included increase of bone height, marginal bone loss (MBL), implant stability, and adverse events such as sinus membrane perforation and signs of infection in the maxillary sinuses. Survival rate and proportion of adverse outcomes were calculated using the variance-stabilizing Freeman-Tukey double-arcsine transformation. Meta-analyses of bone gain and MBL were performed based on changes from baseline and sampling variance. Implant stability was analyzed at follow-up. Individual participant data were modeled using a one-step approach. The survival probability was determined using the Kaplan-Meier method, and the Cox proportional-hazards regression was applied to investigate the association between survival time of implants and covariates.

Results: 11 observational studies were included in the study. The meta-analysis based on 660 implants and 17 failures showed a pooled survival rate of 97.5% (CI 95% 95.8 to 98.9). Pooled analysis also showed an increase in mean bone height of 5.7 mm (CI 95% 4.78 to 6.56), MBL of 1.2 mm (CI 95% 0.84 to 1.51), and implant stability quotient of 70.5 (CI 95% 64.2 to 76.9). A pooled rate of 20.0% (CI 95% 10.9 to 30.6) and 3.0% (CI 95% 0.5 to 6.8), respectively, for membrane perforations and sinus infection was found. Individual-data meta-analysis showed an overall 5-year survival of 93.1% (SE 2.67%) with a mean survival time of 6.7 years (SE 0.08). Longer implants were associated with a decreased hazard ratio (0.64; CI 95% 0.41 to 0.99).

Conclusions: Current available evidence based on aggregate and individual patient data meta-analysis suggests that lateral maxillary sinus floor elevation without grafting, and simultaneous implant placement, is a safe and effective technique with high survival rates, especially for implants with more than 13 mm in length.

Keywords: Dental implants; Evidence-based dentistry; Sinus floor augmentation.