title: Effectiveness of the GentleWave System in Removing Separated Instruments.
abstract: BACKGROUND
  A separated instrument in a root canal system has the potential of severely affecting the outcome of endodontic therapy. This study evaluated the effectiveness of the minimally invasive GentleWave System (Sonendo Inc, Laguna Hills, CA) in removing separated stainless steel endodontic files from the apical and midroot regions of molar root canals.
  
  
  METHODS
  Thirty-six extracted human molars were accessed, and the glide path was confirmed to the apex. ISO #10, #15, and #20 K-file fragments of 2.5-mm length were separated at the apical (n = 18) or midroot (n = 18) region of the molars by engaging a weakened file with downward pressure. During analysis, the teeth were divided into 2 curved groups based on the curvature of the root (<30° and >30°). The success rate of instrument removal and the treatment time were noted. Statistical comparison was done with the Fisher exact test and independent 2-sample t test (P < .05).
  
  
  RESULTS
  The overall success rate of instrument removal when the separated files were engaged in the apical region was 61%, and for the midroot region, it was 83%. Less curved canals (<30°) showed a 91% success rate (n = 24), whereas canals with an angle of curvature greater than 30° showed a 42% success rate (n = 12). The median treatment time for instrument retrieval was 10 minutes 44 seconds.
  
  
  CONCLUSIONS
  The results revealed that the GentleWave System is effective in retrieving separated instruments while conserving the dentinal structure.
authors.affiliation: Department of Endodontics, New York University College of Dentistry, New York, New York.
authors.forename: Pierre
authors.initials: P
authors.lastname: Wohlgemuth
authors.affiliation: Department of Endodontics, New York University College of Dentistry, New York, New York.
authors.forename: Davide
authors.initials: D
authors.lastname: Cuocolo
authors.affiliation: Sonendo Inc, Laguna Hills, California.
authors.forename: Prashanthi
authors.initials: P
authors.lastname: Vandrangi
authors.affiliation: Department of Endodontics, New York University College of Dentistry, New York, New York. Electronic address: asgeir.sigurdsson@nyu.edu.
authors.forename: Asgeir
authors.initials: A
authors.lastname: Sigurdsson
mesh_terms: D003748:Dental Equipment; D003762:Dental Instruments / Q000009:adverse effects*; D005547:Foreign Bodies / Q000628:therapy*; D006801:Humans; D003765:Models, Dental; D008963:Molar / Q000473:pathology; D023861:Photography, Dental; D018915:Root Canal Preparation / Q000295:instrumentation*; D013010:Sonication / Q000379:methods*; D016896:Treatment Outcome
keywords: File separation; GentleWave System; Multisonics Ultracleaning; steel hand files