Packable composites were developed to be used in posterior situations. Unlike flowable composite, they exhibit a higher viscosity thereby necessitating greater force upon application to 'pack' the material into the prepared cavity. Their handling characteristics is more similar to dental amalgam, in that greater force is required to condense the material into the cavity. Therefore, they can be thought of as 'tooth-coloured amalgam'. The increased viscosity is achieved by a higher filler content (>60% by volume) – thereby making the material stiffer and more resistant to fracture, two properties that are ideal for materials to be used in the posterior region of the mouth. The disadvantage of the associated increased filler content is the potential risk of introducing voids along the cavity walls and between each layer of material. In order to seal any marginal deficiencies, the use of a single layer of flowable composite at the base of a cavity has been advocated when undertaking Class II posterior composite restorations when using packable composite.