Purpose: The aim of this study was to analyze the histologic quality and histomorphometric quantity of newly formed bone and the biologic properties after maxillary sinus floor augmentation with biphasic tricalcium phosphate (BCP) prior to dental implant placement. Materials and Methods: The selected alloplastic bone substitute, a blend of 60% hydroxyapatite and 40% β-tricalcium phosphate, was placed into the sinus cavity and covered with a bioresorbable membrane. Ten bone samples were harvested from the grafted sinuses of eight patients at 6 months postsurgery for histologic and histomorphometric analysis during implant placement at stage-two surgery. Results: Histologic analysis of the 10 biopsy specimens showed remaining BCP particles in intimate contact with the newly formed bone. Several areas of bone substitute resorption and new bone remodeling were observed. The mean composition of the bone samples harvested from the grafted sinuses was 26.1% ± 6.3% newly formed bone, 29.3% ± 9.1% remaining BCP particles, and 44.7% ± 7.7% connective tissue/bone marrow. Conclusion: BCP biomaterial was osteoconductive and biocompatible. This biomaterial scaffold promoted the formation of new bone, which was in intimate contact with the remaining bone substitute particles. Within the limits of this study, maxillary sinus floor augmentation using BCP bone substitute is a reliable procedure for dental implant placement. Keywords: beta-tricalcium phosphate, bone substitute, histology, histomorphometry, hydroxyapatite, sinus floor augmentation