Dynamics and risk indicators of intrasinus elevation height following transalveolar sinus floor elevation with immediate implant placement: a longitudinal cohort study

Successful intrasinus graft consolidation is essential for the treatment outcome of transalveolar sinus floor elevation (SFE). This study was performed to examine the dynamics and risk indicators related to the elevation height after transalveolar SFE with grafting material and simultaneous implant placement. Fifty-two patients with 55 sites undergoing transalveolar SFE with immediate implant placement were enrolled retrospectively. Cone beam computed tomography (CBCT) images were collected and saved in DICOM format, at the following time-points: pre-surgery (T0), immediately post-surgery (T1), and 6 months post-surgery (T2). Voxel-based CBCT superimposition was performed to measure the sinus width, residual alveolar height, implant protrusion length, total elevation height, and apical graft height. The change in total elevation height from T1 to T2 was defined as the study outcome. Clinical and linear variables were analysed using linear regression. From T1 to T2, the total elevation height showed an average reduction of 1.0 ± 1.1 mm, while 10.9% sites showed an increased elevation height. Univariate regression analysis showed no significant correlation between tested clinical or linear variables and the study outcome. The results suggest that the change in elevation height was not influenced by the alveolar or sinus dimensions, graft materials, implant diameter, implant protrusion length, or the total elevation height at T1.