title: Cleaning efficacy of two apical preparation regimens following shaping with hand files of greater taper.
abstract: OBJECTIVE
  The aim of this investigation was to assess canal cleaning following shaping with hand files of greater taper.
  
  
  METHODS
  Thirty mesial canals and 30 distal canals in mandibular molars were prepared with .08 and .10 hand files of greater taper, respectively. Following initial preparation, 0.02 instruments were used incrementally shorter in a stepback manner. In half the canals instrumentation was performed to size 35 1 mm short of the canal terminus. In the other half the series was continued through to size 60 using stepback increments of half to one millimetre as appropriate (foramen size was maintained at size 20 in all groups). Sodium hypochlorite (4.5%) and REDTA (17%) were used as irrigants for all groups. Cleaning efficacy was evaluated by scoring the amount of remaining debris using a light microscope (x50) and calibrated eyepiece micrometer (range 0-3).
  
  
  RESULTS
  Canals stepped back through to a size 60 were significantly cleaner than those instrumented to a size 35 only (Mann-Whitney P < 0.05).
  
  
  CONCLUSIONS
  Refining the apical region of canal preparation by stepping back through to a size 60 reduced remaining debris following shaping with files of greater taper.
authors: School of Dentistry, Birmingham, UK.
authors: P J
authors: PJ
authors: Lumley
mesh_terms: D003762:Dental Instruments; D004867:Equipment Design; D006801:Humans; D009532:Nickel; D011897:Random Allocation; D012388:Root Canal Irrigants; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods*; D018709:Statistics, Nonparametric; D014025:Titanium; D019227:Tooth Apex / Q000033:anatomy & histology
chemical_list: D012388:Root Canal Irrigants; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium