Removal of a Separated Nickel-titanium Instrument from a Three-rooted Mandibular First Molar

Abstract

Permanent mandibular first molars usually have a mesial root and a distal root and three root canals, but variations in the number of roots and in canal morphology are not uncommon. The additional third root in permanent mandibular first molar variants that have three roots is typically distributed lingually. Herein, we report on a 20-year-old Chinese female who presented with a separated K3 nickel-titanium instrument in the distolingual root canal of her left mandibular first molar. We removed the nickel-titanium fragment using several ultrasonic tips under a dental operating microscope. The root canals were cleaned and shaped thoroughly and then obturated by a warmed gutta-percha compaction method. At 4-month follow-up, the patient was free of symptoms.