In these endodontic case reports we present a root canal preparation protocol using the Mtwo Ni-Ti rotary files according to the 'simultaneous technique' which is a'crown-down' approach, where every instrument in the sequence is used to the full working length. A hybrid Microseal/PacMac obturation (consisting of three stages: master cone compaction, backfill with pre-plasticized guttapercha and vertical compaction) is proposed in order to: maintain the obturation length control associated with the Microseal system; use preheated gutta-percha to backfill the canal rapidly with the PacMac condensor; and to reduce potential voids in the obturation material with the final vertical compaction. The'simultaneous technique'followed by apical preparation using Mtwo apical files allows obturation using the proposed hybrid Microseal/Pacmac method, aiming to overcome some of the shortcomings of the Microseal and Pacmac obturation methods, such as length control difficulty and sealer pooling.