title: The efficacy of gutta-percha removal using ProFiles.
abstract: OBJECTIVE
  The purpose of this study was to compare the efficacy in vitro of gutta-percha removal from obturated root canals using ProFiles.
  
  
  METHODS
  Forty-eight human root canals with curvatures ranging between 25 and 45 degrees were instrumented by a standardized method to an apical ISO size 30 and 0.04 taper. They were obturated with vertically condensed gutta-percha. Retreatment was performed with the following techniques: K-Flexofiles with chloroform; Hedstrom files with chloroform; ProFiles 0.04 taper with chloroform; ProFiles 0.04 taper alone. The time for each method was measured. A microfocal macroradiographic technique was used to evaluate the amount of debris remaining within the root canals after the retreatment procedure. Roots were divided into apical, middle and coronal parts and scored on a scale of 0 (no debris) to 3 (> 50% of walls covered with debris) by trained observers on two separate occasions.
  
  
  RESULTS
  The scores for debris remaining within root canals for K-Flexofiles with chloroform and ProFiles with chloroform were the lowest and not significantly different at all three levels of the roots examined (P > 0.05), and Hedstrom files with chloroform and ProFiles with chloroform were not significantly different in the apical part. In general, coronal parts were cleaner than apical parts. The difference in scores at the three levels between ProFiles with chloroform and ProFiles alone were each significant (P < 0.01). Instrumentation using ProFiles with chloroform (mean 6.42 min) was significantly faster than using hand files (mean 11.67 min) (P < 0.01).
  
  
  CONCLUSIONS
  The results indicated that ProFiles or hand files with chloroform produced similarly clean canals, but that ProFiles were faster.
authors.affiliation: Department of Conservative Dentistry, Guy's, King's and St. Thomas' Dental Institute, Kings College, London, UK.
authors.forename: J J
authors.initials: JJ
authors.lastname: Ferreira
authors.forename: J S
authors.initials: JS
authors.lastname: Rhodes
authors.forename: T R
authors.initials: TR
authors.lastname: Ford
mesh_terms: D002725:Chloroform / Q000737:chemistry; D003722:Dental Alloys; D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging / Q000648:ultrastructure; D004867:Equipment Design; D006171:Gutta-Percha / Q000737:chemistry; D006801:Humans; D015588:Observer Variation; D011859:Radiography; D012387:Root Canal Filling Materials / Q000737:chemistry; D012389:Root Canal Obturation; D018915:Root Canal Preparation / Q000295:instrumentation*; D012997:Solvents / Q000737:chemistry; D013223:Statistics as Topic; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013997:Time Factors; D019227:Tooth Apex / Q000000981:diagnostic imaging / Q000648:ultrastructure
chemical_list: D003722:Dental Alloys; D012387:Root Canal Filling Materials; D012997:Solvents; D002725:Chloroform; D006171:Gutta-Percha