Three-dimensional changes and influencing factors of tent space following osteotome sinus floor elevation without grafting: A 48-month retrospective radiographic study

ObjectivesTo analyze the three-dimensional stability and morphologic changes of tent space after the osteotome sinus floor elevation (OSFE) procedures without bone grafts.Materials and MethodsForty-six implants placed using the OSFE technique with simultaneous implant placement without bone grafts were included in this retrospective study. Cone-beam computed tomography (CBCT) scans of the augmented sinuses were obtained pre- and postoperatively up to 48 months of follow-up. The maxillary sinus cavity profiles were outlined using three-dimensional virtual reconstruction and superimposition of CBCT scans. The three-dimensional changes in the tent space were measured. A generalized estimating equation (GEE) was used to explore potential factors.ResultsThe implant survival rate was 97.8%. The mean volume of remaining tent space immediately after surgery was 96.8 +/- 70.5 mm3, shrinking to 31.0 +/- 24.9 mm3 after 48 months, while the mean percentage of remaining tent space volume decreased to 29.1 +/- 20.7%. The tent space volume and the percentage of residual tent space volume only decreased significantly within 12 months after surgery (p = .008, .013). GEE results indicated positive correlations between the percentage of remaining tent space volume and implant protrusion length (p = .000) and apical height (p = .000), with a negative correlation between the sinus floor area immediately after surgery (p = .002) and the healing time (p = .022).ConclusionsThe volume of the tent space rapidly shrank after OSFE without bone grafts. Several factors might influence the tent space stability. Long-term clinical trials with larger sample sizes are necessary to further validate the results.