Failing implants lead to osseous defects. Guided tissue regeneration made of bioactive ceramics has been used to promote bone formation in osseous deformation. The aim of this study was to prepare and to characterize the fluorapatite/forsterite nanocomposite powder for treatment of oral bone defects. In this study, these composite powders with different contents of forsterite nanopowder were prepared via sol-gel process. Characterization of prepared nanocomposite powders and their cytotoxicity evaluation were done and compared with pure forsterite and fluorapatite powders. Results showed that nanocomposite powders with crystallite size of about 21–24 nm were fabricated successfully by gel calcination at 600°C. Besides the non-toxicity effects of powders, nanocomposite containing 20 wt% forsterite significantly increased cell viability compared with control groups. According to these results, these nanocomposite powders might be suitable as bioactive material for oral bone defect.