In this study, ninety extracted endodontically treated mandibular molars were mounted in acrylic resin blocks. Five groups of eighteen extracted teeth were prepared by two different techniques. A peripheral shelf 2 mm deep and 1.4 mm wide was prepared as a first technique, while TMS pins were used in the second group. The teeth were then restored with five different core materials: silver-reinforced glass-ionomer, resin-modified glass-ionomer, self-cured glass-ionomer, polyacid-modified composite resin, and titanium-reinforced composite resin. An Instron testing machine was used to apply shear force at a crosshead speed of 2 mm/min until fracture occurred. The results were obtained statistically using analysis of variance and least significant difference tests. According to the results of this study, Ti-core and composite resin were the strongest core materials when subjected to shear forces, and the most retentive preparation design was the vertical-pin design. The fractures of these materials with a vertical-pin design were mostly seen at the core and the tooth.