Stepwise Modified Transcrestal Sinus Floor Elevation in Sites With 3-5-mm Residual Bone Height: A Retrospective Study

This retrospective study compared the clinical and radiographic outcomes of a stepwise modified transcrestal sinus floor elevation (SM-TSFE) with the lateral sinus floor elevation (LSFE) for simultaneous implant placement in sites with 3-5 mm of residual bone height (RBH).

A total of 149 patients with 3-5-mm RBH underwent simultaneous implant placement using either SM-TSFE (n = 69) or LSFE (n = 80). The follow-up period ranged from 6 months to 8 years. Evaluated clinical outcomes included implant survival rates, sinus membrane perforation, and postoperative complications. Radiographic assessments included preoperative RBH, marginal bone loss (MBL), and vertical bone height changes.

Cumulative implant survival rates were comparable between SM-TSFE (91.30%) and LSFE (93.75%) groups (p = 0.537). However, the SM-TSFE group demonstrated a significantly lower sinus membrane perforation rate (7.24%) compared to the LSFE group (18.75%; p = 0.047). Multivariate analysis identified maxillary sinus septa as the strongest risk factor for perforation (p = 0.002). Regarding implant failure, TiUnite surface (p = 0.035) and membrane perforation (p = 0.039) were significant risk factors, while higher marginal bone height (MBH) was identified as a protective factor (p = 0.003). Both groups exhibited comparable MBL at 2 years post-loading (p > 0.05).

In sites with 3-5 mm of RBH, SM-TSFE provides implant survival rates comparable to LSFE over the observation period but offers a significant safety advantage due to a substantially lower rate of sinus membrane perforation.