Distortion and breakage of Liberator, EndoSequence, and ProFile systems in severely curved roots of molars.

Introduction: The aim of this study was to investigate the incidence of endodontic file distortion and breakage when the Liberator (Miltex Inc, York, PA), EndoSequence (Brasseler USA, Savannah, GA), and ProFile (Tulsa Dental Products, Tulsa, OK) systems were used to instrument severely curved root canals of extracted human molars.

Methods: Eighty-four roots of extracted human molars with curvatures measuring 40 degrees to 80 degrees were used. The roots were randomly assigned into four groups based on the rotary instrumentation system: group 1, ProFile (.