Purpose: The objectives of this retrospective study were to describe a transcrestal sinus floor elevation technique combining the use of a hydraulic device and a nanohydroxylapatite paste and to report on 4-year clinical and radiographic outcomes.

Materials and methods: The sinus floor elevation procedure used a specially designed drill (SinusJet) to start sinus membrane unsticking and a nanohydroxylapatite paste (Ostim) for further sinus membrane elevation and bone augmentation. It was performed as a one-step procedure with immediate implant placement or a two-step procedure with delayed implant placement 9 months later. Implant survival rate, sinus membrane perforation, postoperative complications, and the level of intraoperative and postoperative patient comfort using a visual analog scale were analyzed retrospectively. A nonparametric Wilcoxon matched-pairs test and parametric paired t test were used to identify significant differences.

Results: One hundred thirty-six sinus floor elevations were performed in 110 patients at two dental clinics in Belgium with a mean follow-up period of 48 months. In the one-step procedure, the mean 6-month elevation was 8.5 ± 2.7 mm; 194 implants were placed. In the two-step procedure, the mean 9-month elevation was 9.5 ± 2.4 mm; 8 implants were placed. The osteotomy, sinus membrane elevation, and bone grafting typically took less than 3 minutes. Sinus membrane perforation was observed in 2.9% (n = 4/136). The 4-year implant survival rate was 97% (n = 196/202), with six early implant losses. 96.4% of patients reported either no or minimal discomfort.

Conclusion: This minimally invasive transcrestal sinus floor elevation procedure that combines a hydraulic device and nanohydroxylapatite paste appears to be safe and predictable. However, further randomized controlled studies are needed to validate the results of this retrospective observational study.