title: Geometric analysis of maxillary first premolar prepared by two nickel-titanium rotary instruments.
abstract: OBJECTIVE
  The present study was conducted with the aim of evaluating and comparing the shaping ability of two Nickel-titanium rotary instruments, with two disparate design features, on root canal geometry of extracted human maxillary first premolars using microcomputed tomography.
  
  
  METHODS
  Twenty four bifurcated maxillary first premolars were divided into two groups and embedded in a rubber-based impression material. Both groups were submitted to micro-computed tomography before and after canal preparation (buccal and palatal) with either ProFile Vortex or Revo-S rotary instruments. Images were reconstructed and cross-sections corresponding to a distance 1, 2, 3, 4, 5, 6, and 7 mm from the anatomical apex were selected for canal transportation analysis. Volume changes were also measured.
  
  
  RESULTS
  The degree and direction of canal transportation were non-significant for both instruments. Statistically significant differences were observed only between levels in the buccal canal in both groups. There was no significant difference between the two rotary systems in regards to the volume of dentin removed.
  
  
  CONCLUSIONS
  Our findings showed that ProFile Vortex and Revo-S instruments respected the original root canal anatomy and behaved similarly. ProFile Vortex rotary systems produced with innovative process were concluded to shape the upper maxillary premolar by leading minimal canal transportation, similar to Revo-S, rotary systems produced from traditional process.
authors.affiliation: Associate Professor and Consultant, Endodontic Division, Department of Restorative Dental Sciences, College of Dentistry, King Saud University, Saudi Arabia.
authors.forename: Dina
authors.initials: D
authors.lastname: Al-Sudani
authors.affiliation: Endodontist, Department of Dentistry, King Fahd Military Medical Complex Dhahran, Saudi Arabia.
authors.forename: Majed
authors.initials: M
authors.lastname: Almalki
authors.affiliation: Endodontist, Department of Dentistry, Armed Forces Hospital, Dhahran Saudi Arabia.
authors.forename: Saad
authors.initials: S
authors.lastname: Al-Shahrani
authors.affiliation: Associate Professor, Department of Dental Medicine, Cariology and Endodontology Division, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Michael
authors.initials: M
authors.lastname: Ahlquist
mesh_terms: D019412:Anatomy, Cross-Sectional; D001641:Bicuspid / Q000033:anatomy & histology*; D003722:Dental Alloys / Q000737:chemistry*; D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D003804:Dentin / Q000033:anatomy & histology; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008422:Materials Testing; D008433:Mathematics; D008437:Maxilla; D009532:Nickel / Q000737:chemistry*; D018915:Root Canal Preparation / Q000295:instrumentation*; D012399:Rotation; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D019227:Tooth Apex / Q000033:anatomy & histology; D055114:X-Ray Microtomography / Q000379:methods
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium