Endodontic surgical procedures involve the use of a root-end filling material to provide an apical seal and to facilitate the repair and regeneration of periradicular tissues. Whereas earlier studies typically evaluated the cytotoxicity of these materials, contemporary research has focused on their capacity to support a favourable cellular response. In vitro tissue culture techniques have demonstrated interactions at the cell surface that may be conducive to periapical healing. Recent research with osteoblasts has confirmed their affinity for novel endodontic mineral trioxide aggregate (MTA) materials, with evidence of cell attachment and synthesis of bone matrix. This article reviews the current state of knowledge about MTA as a root-end filling material, with particular emphasis on cellular response to MTA materials.