title: Evaluation of morphological changes produced by orifice opener systems using computerized tomography (CT).
abstract: OBJECTIVE
  To evaluate modifications in root canal morphology following instrumentation with orifice openers using Computerized Tomography (CT).
  
  
  METHODS
  Experimental in vitro study. A preoperative CT was performed on 49 molars to measure the root canal cross-sections. After preparing the canals with 6 different nickel-titanium (Ni-Ti) rotary system orifice opener type instruments and Gates Glidden burs, a further CT was made and compared with the preoperative one. Kruskal-Wallis and ANOVA statistical analysis were used.
  
  
  RESULTS
  Gates Glidden burs were significantly more aggressive in the coronal portion of the canals, although all the instruments removed more dental tissue in the most coronal of the sections studied. Bucco-lingual diameters were modified more than the mesio-distal ones. The stainless steel instruments used lead to greater modifications being required in the canals than those made of nickel-titanium. The ProFile system instruments were observed to be those that caused the least amount of change.
  
  
  CONCLUSIONS
  Stainless steel burs are more aggressive than new orifice openers without significant differences observed between Ni-Ti instruments.
authors.affiliation: Universidad CEU - Cardenal Herrera, Moncada, Spain.
authors.forename: Adela
authors.initials: A
authors.lastname: Hervás
authors.forename: Leopoldo
authors.initials: L
authors.lastname: Forner
authors.forename: Carmen
authors.initials: C
authors.lastname: Llena
authors.forename: Eduardo
authors.initials: E
authors.lastname: Zaragoza
mesh_terms: D003786:Dental Pulp Cavity / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D006801:Humans; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods; D014057:Tomography, X-Ray Computed