title: Assessment of canal walls after biomechanical preparation of root canals instrumented with Protaper Universal rotary system.
abstract: OBJECTIVE
  The aim of this study was to examine the instrumented walls of root canals prepared with the ProTaper Universal rotary system.
  
  
  METHODS
  Twenty mesiobuccal canals of human first mandibular molars were divided into 2 groups of 10 specimens each and embedded in a muffle system. The root canals were transversely sectioned 3 mm short of the apex before preparation and remounted in their molds. All root canals were prepared with ProTaper Universal rotary system or with Nitiflex files. The pre and postoperative images of the apical thirds viewed with a stereoscopic magnifier (X45) were captured digitally for further analysis. Data were analyzed statistically by Fisher's exact test and Chi-square test at 5% significance level.
  
  
  RESULTS
  The differences observed between the instrumented and the noninstrumented walls were not statistically significant (p<0.05).
  
  
  CONCLUSIONS
  The Nitiflex files and the ProTaper Universal rotary system failed to instrument all the root canal walls.
authors.affiliation: Department of Prosthodontics and Oral and Facial Surgery, Federal University of Pernambuco, Recife, PE, Brazil. cmaguiar.ufpe@yahoo.com.br
authors.forename: Carlos Menezes
authors.initials: CM
authors.lastname: Aguiar
authors.forename: Daniela de Andrade
authors.initials: Dde A
authors.lastname: Mendes
authors.forename: Andréa Cruz
authors.initials: AC
authors.lastname: Câmara
authors.forename: Antonio Poli de
authors.initials: AP
authors.lastname: Figueiredo
mesh_terms: D001696:Biomechanical Phenomena; D003722:Dental Alloys / Q000737:chemistry; D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D004492:Edetic Acid / Q000627:therapeutic use; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008422:Materials Testing; D008963:Molar / Q000473:pathology; D009532:Nickel / Q000737:chemistry; D012388:Root Canal Irrigants / Q000627:therapeutic use; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D012399:Rotation; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry; D019227:Tooth Apex / Q000473:pathology
chemical_list: D003722:Dental Alloys; D012388:Root Canal Irrigants; C040654:titanium nickelide; D009532:Nickel; D004492:Edetic Acid; D014025:Titanium; D012973:Sodium Hypochlorite