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Rationale for the use of low‐torque endodontic motors in root canal instrumentation
Author(s) -
Gambarini G.
Publication year - 2000
Publication title -
dental traumatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 81
eISSN - 1600-9657
pISSN - 1600-4469
DOI - 10.1034/j.1600-9657.2000.016003095.x
Subject(s) - torque , instrumentation (computer programming) , root canal , fracture (geology) , nickel titanium , materials science , orthodontics , computer science , medicine , metallurgy , physics , composite material , shape memory alloy , thermodynamics , operating system
Abstract – Fracture of nickel‐titanium rotary files is an iatrogenic error which can seriously jeopardize root canal therapy. If a high‐torque motor is used, the instrument‐specific limit‐torque (fracture limit) is often exceeded, thus increasing the risk of intracanal failure. A possible solution to this problem is to use a low‐torque endodontic motor which operates below these values. If the torque is set just below the limit of elasticity for each instrument, the risk of fracture is likely to be markedly reduced. The purpose of this paper was to discuss mechanical properties of NiTi rotary instruments, the rationale for selecting low torque values, and to use clinically a new endodontic motor (step‐motor) which operates below the limit of elasticity of each rotary file. The step‐motor was found to be helpful in reducing the risk of instrument fracture. Irreversible material damage (plastic deformation) and instrument fracture were rarely seen. Low‐torque instrumentation also increased tactile sense and, consequently, mental awareness of rotary instrumentation.