This case report is focused on the histologic findings of bone tissue supplied with two different hydroxyapatites (HAs) used for maxillary sinus floor grafting in the same patient after various healing intervals. An insufficient unilateral sinus floor grafting with Bio-Oss biomaterial was followed by an additional grafting procedure with Algipore biomaterial performed 4 years later. Bone samples obtained during second-stage dental implantation contained the interesting combination of Bio-Oss, a bovine anorganic bone substitute, and Algipore, a porous algae-derived HA, in close vicinity, yet after different healing periods. Light microscopy exhibited satisfactory osseointegration of both grafting materials. However, Bio-Oss biomaterial showed no evidence of substantial remodeling after a healing period of 4.5 years. On the other hand, Algipore particles demonstrated signs of remodeling by being locally resorbed and partially replaced with newly formed bone already within 6 months.