title: A comparison of spreader penetration depth and load required during lateral condensation in teeth prepared using various root canal preparation techniques.
abstract: OBJECTIVE
  To compare the influence of various root canal preparation techniques on spreader penetration depth and load required during lateral condensation with gutta-percha and sealer.
  
  
  METHODS
  Eighty extracted human teeth with single and straight canals were used. Twenty teeth were instrumented using one of four root canal preparation techniques. The four preparation techniques were: step-back technique without Gates-Glidden drills, step-back technique with Gates-Glidden drills, crown-down pressureless technique and hybrid technique (step-down/step-back). After root canal preparation had been completed a simulated periodontal ligament was fabricated from a uniform layer of silicone impression material. The roots were then mounted in an acrylic resin to simulate the physical condition found in tooth socket. A standardized stainless steel hand spreader of the same size as the master apical file was mounted in an Instron testing machine and lateral compaction with gutta-percha and sealer was performed. The load value was recorded from the Instron testing machine. The spreader penetration depths were measured with an endodontic ruler. The data obtained were analysed statistically using anova and Student's t-tests.
  
  
  RESULTS
  No significant difference in initial spreader load needed to condense the master cone was found amongst the four canal preparation techniques (P > 0.05). The step-back technique with Gates-Glidden drills and the hybrid technique demonstrated the least difference between the initial spreader penetration and the working length (mean 1.925 and 2.25 mm, respectively). The step-back technique without Gates-Glidden drills and the crown-down pressureless technique had the greatest difference between initial spreader penetration and the working length (mean 4.425 and 4.75 mm, respectively).
  
  
  CONCLUSIONS
  The flare created by canal preparation affected spreader penetration depth, but had no effect on the spreader load.
authors: Dental Technologies Department, College of Health and Medical Technologies, Foundation of Technical Education, Baghdad, Iraq. sf_dulaimi@yahoo.com
authors: S F
authors: SF
authors: Dulaimi
authors: M K
authors: MK
authors: Wali Al-Hashimi
mesh_terms: D003786:Dental Pulp Cavity / Q000033:anatomy & histology* / Q000502:physiology; D003799:Dental Stress Analysis / Q000295:instrumentation; D004867:Equipment Design; D006171:Gutta-Percha / Q000737:chemistry; D006801:Humans; D008953:Models, Anatomic; D010513:Periodontal Ligament / Q000033:anatomy & histology; D012387:Root Canal Filling Materials / Q000737:chemistry*; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D013193:Stainless Steel; D013314:Stress, Mechanical; D020390:Tooth Socket / Q000033:anatomy & histology
chemical_list: D012387:Root Canal Filling Materials; D013193:Stainless Steel; D006171:Gutta-Percha