Purpose: The purpose of this prospective, randomized, clinical pilot study was to compare the threedimensional changes of grafted maxillary sinuses when deproteinized bovine bone (DBB) or cortical mineralized allogeneic bone (MAB) was used. Materials and Methods: Seventeen patients were randomly assigned to receive either DBB or MAB for lateral-approach maxillary sinus augmentation. Cone beam computed tomography (CBCT) scans were performed preoperatively (T0), immediately after (T1), and at approximately 6 months postoperatively (T2). Three-dimensional analysis of the radiographic volumetric changes was performed for DBB and MAB by measuring the difference in unoccupied sinus volumes at T1 and T2. Results: In the DBB group, a statistically significant increase in unoccupied sinus volume was found at T2 when compared to T1 (P = .001), representing a mean resorption rate of 23.8% ± 15.9%. Similarly in the MAB group, a statistically significant increase in unoccupied sinus volume was found at T2 when compared to T1 (P = .007); the mean resorption rate in the MAB group was 19.5% ± 10.1%. There was no statistically significant difference between the contraction of DBB (23.8%) and MAB (19.5%) (P = .52). Conclusion: Both DBB and MAB showed sufficient volume stability at T2 (mean: 6.3 ± 1.6 months) postoperatively for 10- to 13-mm-implant placement without the need for additional grafting. Keywords: bone remodeling, bone substitute, dental implants, maxillary sinus