Purpose of the study. Comparative morphometric evaluation of the crestal bone condition in patients after open and closed sinus lifting using cone-beam computed tomography (CBCT). Material and methods. The study included 78 patients who underwent dental implantation with two types of sinus lifting: open (n = 40) and closed (n = 38). CBCT was performed with a slice thickness of 0.1 mm and voxel size of 0.15 mm. The following parameters were analyzed: crestal bone height, cortical plate thickness, bone density (HU), contour symmetry index (%), and frequency of microresorption (%). Statistical analysis was performed using the Student’s t-test (p < 0.05). Research results. Morphometric analysis revealed significantly better parameters of crestal bone after closed sinus lifting compared to the open technique: bone height - 3.42 ± 0.30 mm vs. 2.85 ± 0.35 mm (p < 0.01); cortical thickness - 0.96 ± 0.09 mm vs. 0.83 ± 0.08 mm (p < 0.05); density - 1015 ± 40 HU vs. 945 ± 45 HU (p < 0.01); and microresorption frequency - 8.1% vs. 17.5% (p < 0.05). Conclusions. Closed sinus lifting ensures greater preservation of the crestal bone, higher mineral density, and reduced microresorption rates compared to the open approach. The obtained results confirm the biomechanical and clinical advantages of the closed method in ensuring long-term implant stability and predictable osteointegration.