Chewing food is a dynamic and continuous process. tooth is an important component which can not be neglected. Accordingly to WHO(world health organization) report nearly 100% people have decay once in life. Decay can be filled with gold, silver amalgam. Composites have advantages by providing natural colour of tooth, less tooth removal required to fill cavity and natural tooth structure can be maintained. The aim of this work is to present an analysis of the composites and furnish dentists with a basis that can provide criteria for choosing one or another to suit their treatment. The mechanical properties of composite resins are importantly depends upon filler content. Dental composites are using silica, quartz and alumina glass as filler for long time. Zirconia is the latest addition as filler. Chewing of food is a dynamic situation in which many forces are acting in all possible direction, the most important being the flexural force. Our aim is to optimise the flexural strength in Zirconia nanoclusters of the Bis-GMA & TEGDMA based dental composites. The aim of work is to find out best combination of composite material.