Comparative study between the radiopacity levels of high viscosity and of flowable composite resins, using digital imaging - Vasconcellos, Beatriz Tholt de; Thompson, JY; Macedo, M. R. de Paula; Maia, J. M. de Oliveira; Oda, Margareth; Garone Netto, Narciso (The european journal of esthetic dentistry, 2013)