Abstract : To compare PRF and PRF+BEGO-OSS® as bone augmentation materials in terms of bone level and bone quality. A split-mouth study on 12 patients to replace the missing upper first molar tooth. Twenty implants were inserted simultaneously with the sinus lift procedure. Augmentation was performed with PRF on one side, and PRF+ BEGO-OSS® on the other side. CBCT scans were taken for the included cases preoperatively and 4 months postoperatively. Both bone height and quality measurements were taken for the buccal, palatal, mesial, and distal sides of each implant. The level of bone gain was slightly higher on the PRF+ BEGO-OSS® side. However, the difference in bone gain between the treatment sides has not been statistically confirmed (P= 0.135). The bone quality increase was higher in both buccal and palatal areas in the PRF treatment sides. A bone quality decrease in mesial and distal surfaces was noticed on the PRF side. The difference in bone gain between the treatment sides has not been statistically confirmed (P= 0.135). Augmentation with (BEGO-OSS®) bone graft does not seem to add a significant value to the use of PRF in the maxillary sinus-lift procedure.