Radiographic inhomogeneity of posterior composites

A radiographic technique has been devised for determining the structural inhomogeneity between successive specimens fabricated from any given dental composite. This has been applied to nineteen composites currently recommended for the restoration of Class I and Class II cavities. The inhomogeneity data fell within clearly defined bands, with some light-cured posterior composites exhibiting an inhomogeneity parameter of zero. Other hands had average inhomogeneities of 1.5%, 2.5%, 3.8% and 6.8%. The level of inhomogeneity exhibited by a composite system may be an important factor in material selection and in long-term clinical performance.