Bertrand, M F Curved molar root canal preparations using Hero 642 rotary nickel-titanium instruments. [electronic resource] - International endodontic journal Dec 2001 - 631-6 p. digital Publication Type: Evaluation Study; Journal Article ISSN: 0143-2885 Standard No.: 10.1046/j.1365-2591.2001.00440.x doi Subjects--Topical Terms: AdultDental Instruments--standardsHumansMolarNickelRoot Canal Preparation--instrumentationStainless SteelTitanium