title: Evaluation of three instrumentation techniques at the precision of apical stop and apical sealing of obturation.
abstract: OBJECTIVE
  The aim of this study was to investigate the ability of two NiTi rotary apical preparation techniques used with an electronic apex locator-integrated endodontic motor and a manual technique to create an apical stop at a predetermined level (0.5 mm short of the apical foramen) in teeth with disrupted apical constriction, and to evaluate microleakage following obturation in such prepared teeth.
  
  
  METHODS
  85 intact human mandibular permanent incisors with single root canal were accessed and the apical constriction was disrupted using a #25 K-file. The teeth were embedded in alginate and instrumented to #40 using rotary Lightspeed or S-Apex techniques or stainless-steel K-files. Distance between the apical foramen and the created apical stop was measured to an accuracy of 0.01 mm. In another set of instrumented teeth, root canals were obturated using gutta-percha and sealer, and leakage was tested at 1 week and 3 months using a fluid filtration device.
  
  
  RESULTS
  All techniques performed slightly short of the predetermined level. Closest preparation to the predetermined level was with the manual technique and the farthest was with S-Apex. A significant difference was found between the performances of these two techniques (p<0.05). Lightspeed ranked in between. Leakage was similar for all techniques at either period. However, all groups leaked significantly more at 3 months compared to 1 week (p<0.05).
  
  
  CONCLUSIONS
  Despite statistically significant differences found among the techniques, deviations from the predetermined level were small and clinically acceptable for all techniques. Leakage following obturation was comparable in all groups.
authors.affiliation: Department of Restorative Dentistry and Endodontics, Faculty of Dentistry, Yüzüncü Yıl University, Van, Turkey.
authors.forename: Özgür
authors.initials: Ö
authors.lastname: Genç
authors.forename: Tayfun
authors.initials: T
authors.lastname: Alaçam
authors.forename: Guven
authors.initials: G
authors.lastname: Kayaoglu
mesh_terms: D003722:Dental Alloys; D003762:Dental Instruments; D003763:Dental Leakage; D004867:Equipment Design; D006801:Humans; D008422:Materials Testing; D009532:Nickel; D009811:Odontometry / Q000295:instrumentation*; D015203:Reproducibility of Results; D012387:Root Canal Filling Materials / Q000737:chemistry; D012389:Root Canal Obturation / Q000295:instrumentation* / Q000379:methods; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D013193:Stainless Steel; D013997:Time Factors; D014025:Titanium; D019227:Tooth Apex / Q000033:anatomy & histology*
chemical_list: D003722:Dental Alloys; D012387:Root Canal Filling Materials; C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium