Effect of biological degradation on surface hardness and roughness of esthetical restorative materials - Puppin-Rontani, R.M.; Oliveira-Junior, C.C.; Naufel, F.S.; Padovani, G.C.; Paula, A.B.; Araujo, G.S.A.; Correr-Sobinho, L.; Ambrosano, G.M.B. (Dental Materials, 2012)