What is the minimum recommended ferrule height for adequate crown retention and fracture resistance of an endodontically treated tooth?

The literature consistently recommends a minimum ferrule height of 2.0 mm (360 degrees around the tooth preparation) to provide adequate fracture resistance and retention for crowns on endodontically treated teeth. The ferrule effect involves the metal collar of the crown encircling sound tooth structure above the crown margin, counteracting the wedging forces of the post and resisting fracture under occlusal loading. A 1.5 mm ferrule provides some benefit but is considered the absolute minimum; 2.0 mm is the standard clinical recommendation per Carranza's and multiple biomechanical studies.