Resin-based dental composite materials also referred to as “dental composite” are widely used in dentistry to provide direct aesthetic tooth-resembling restorations. These materials are composed of two phases: an organic resin matrix and the inorganic/organic filler. Organic resin matrix phase is made from a mixture of multifunctional monomers and light-sensitive initiators while inorganic/organic filler phase contains micro/nano-sized fillers, which are mainly used as reinforcement. In situ polymerization of dental resin composite by light-irradiation forms a highly crosslinked polymer network that restores the missing tooth structure. One of the major draw back of composite is Polymerization shrinkage .It has 3 implications on the long-term stability of a composite resin. As a result of the polymerization process, the liquid or resin is converted into a solid, which results in a density change that reduces the overall volume. These phenomena can lead to internal stresses and stresses at the margins of the restoration. These stresses, over time, can lead to marginal leakage and secondary caries. B1.1 Discuss composition of dental composite ( 6 marks) B1.2 Explain any two methods to reduce polymerization shrinkage of dental composite (4marks)