LIBS analysis of the cleaning performed by a Nd:Yag laser on used Nickel Titanium instruments

Abstract

Introduction: used endodontic instruments retain dentin debris which represents a biological risk that affects their sterilization. Objective: to assess the cleaning of NiTi endodontic instruments treated with an Nd:Yag laser using the laser-induced plasma spectroscopy (LIBS) technique. Materials and methods: ProTaper Next X2 instruments (Dentsply Maillefer®, Ballaigues, Switzerland) and WaveOne Gold Primary (Dentsply Maillefer®, Ballaigues, Switzerland) were evaluated under a stereoscopic microscope (20X) in 2 stages: 1) used instruments, 2) instruments cleaned with ultrasonics or Nd:Yag laser. In both stages, the presence and extent of dentin debris stained with Van Gieson solution were recorded. Subsequently, the elements contained in the dentin debris found in used NiTi instruments and treated with different cleaning methods were analyzed with the LIBS technique. Results: the Nd:Yag laser technique presented more cleaning capacity (p < 0.0001). The LIBS analysis did not show spectra of elements contained in the biological debris in the instruments treated with both methods. Conclusions: the Nd:Yag laser is an effective method for cleaning NiTi instruments by removing the elements contained in the dentin debris from its surface.