Effect of Preheating on the Microhardness of Nanohybrid Resin-based Composites - Jafarzadeh-Kashi, Tahereh-S; Fereidouni, Farinaz; Khoshroo, Kimia; Heidari, Soolmaz; Masaeli, Reza; Mohammadian, Manijeh (Frontiers in Biomedical Technologies, 2015)