A route to design a dental composite material with the optimum properties to maximize its clinical performance is identified. The structure of composite materials which consist of a particulate filler and fluid binder are analyzed. Composites are shown to have two main matrix structres. The two parameters which govern the structure of a composite are the proportions of fluid and filler and the natural voidage of the latter. A methodology is evolved to develop a composite with a desired matrix structure which includes mathematical model to predict voidage of particulate size distribtions in random mixtures.