Aim The aim of this retrospective study was to quantify three-dimensional (3D) volumetric bone changes over a two-year period in maxillary sinuses augmented with a mineralized cortical bone allograft material (MCBA) material. Patients and Methods Eleven patients (6 males and 5 females) with mean of age of 51.6 (range: 46-61) years were treated to increase the vertical dimension of the alveolar crest by maxillary sinus floor augmentation procedure. Study data were collected from patient records and by analyzing preoperative radiographs and cone beam computed tomography (CBCT) scans taken within the first two weeks after maxillary sinus lift (T0), immediately before implant placement four months after grafting (T1), and after one year of implant loading (T2). All DICOMformatted images were rendered into volumetric images using software that automatically calculated the volume of the grafted material in cubic centimeters. Results Mean graft volume was 16.24 ± 1.54 cm 3 at T0, 14.48 ± 1.48 cm 3 at T1 and 13.06 ± 1.39 cm 3 at T2. Mean volume retraction resulted in 1.76 ± 0.34 cm 3 DV1 (T0-T1) and 1.42 ± 0.4 cm 3 DV2 (T1-T2) and was 10.83 % of the initial total volume at (T0-T1) and 9.8 % of the total volume (T1-T2). Conclusion The present retrospective investigation demonstrated a 20.63 % decrease in graft volume. Volumetric 3D assessment of CBCT scans with the selected software appeared to be a promising approach to quantifying longterm changes in the grafted area.