Research on the development of an ideal dental composite is still ongoing and is focused more on the filler content and polymerization. Silica is an important filler used in several commercial dental composites. At present the silica used in the fabrication of dental composites is synthesized by the classic sol-gel method, using toxic and expensive precursors and chemicals. Rice husk is an abundant source of silica and Malaysia is a major rice producing country. This study is aimed at extracting spherical nanosilica from rice husk using an environment friendly and inexpensive method, and its inclusion as fillers in dental nanocomposites. Spherical nanosilica was extracted from rice husk using a simple precipitation method employing non-toxic chemicals. The dental nanocomposite thus prepared was subjected to flexural strength and modulus tests, which are important tests for predicting the strength of materials. The flexural strength of the dental composite was 82 MPa and the modulus was 6.8 GPa. The results indicate that rice husk, which is an agricultural waste, is a good and inexpensive source of silica to be used as fillers for fabrication of dental nanocomposites with good mechanical properties.