Direct post-core pattern fabrication (subgroups ZN and ZW)
Post spaces were irrigated with 2.5% NaoCl, normal saline and 70% alcohol then partially dried with air/water syringe then completely dried using endodontic paper points. Plastic posts were firstly inserted into specimens’ canals to check its fitting passively, each plastic post was marked to the predetermined length; 10 mm length, then was inserted back to confirm the proper seating [Light-cured universal modelling acrylic resin of gel-consistency (Sedradent, TDV Co. Pomerode, Santa Catarina, Brazil)was injected into each prepared canal around the plastic post, slight bumping motion was done without any excessive pressure, to the predetermined length. Light-curing of the material was done for 20 seconds and 1500 mW/cmThe core was built with the same material; light-cured universal modelling acrylic resin of paste-consistency (Sedradent, TDV Co. Pomerode, Santa Catarina, Brazil) with the same dimensions of core of GN and GW subgroups. After obtaining the proper dimensions, the core was finished and polished using composite finishing and polishing burs [