title: Changes in diameter, cross-sectional area, and extent of canal-wall touching on using 3 instrumentation techniques in long-oval canals.
abstract: OBJECTIVE
  The objective of this study was to compare the shaping ability of manual H-files, rotary nickel-titanium ProTaper system, and reciprocating SafeSiders in long oval-shaped root canals.
  
  
  METHODS
  The roots of 45 human premolars were sectioned at 2 levels in the middle third and reassembled using a 3-piece metal mold. Pre- and postinstrumentation cross-sectional images were superimposed and evaluated in terms of change in buccolingual-to-mesiodistal canal ratio, maximum buccolingual and mesiodistal canal dimensions, and cross-sectional areas. Ratios of touched canal wall and canal outline with more than 200 μm dentin removal to the original canal perimeter were also calculated.
  
  
  RESULTS
  The buccolingual-to-mesiodistal ratio decreased after instrumentation with no difference among techniques (P > .05). The change in the buccolingual dimension was significantly less for SafeSiders compared with H-files and ProTaper (P < .05). The change in mesiodistal dimension was significantly less with SafeSiders compared with H-files only (P < .05). The change in area, in descending order, was as follows: H-files > ProTaper > SafeSiders (P < .05). The ratio of touched canal outline was highest with H-files, compared with ProTaper and SafeSiders (P < .05), and H-files recorded the highest ratio of canal outline with more than 200 μm of dentin thickness removal (P < .05).
  
  
  CONCLUSIONS
  None of the 3 instrumentation techniques completely prepared the oval root canal. Manual and rotary NiTi instrumentation may perform better than reciprocating SafeSider instrumentation in shaping oval canals.
authors.affiliation: Department of Endodontics, Faculty of Oral and Dental Medicine, Cairo University, Cairo, Egypt.
authors.forename: Ghada El
authors.initials: GE
authors.lastname: Hilaly Eid
authors.forename: Suzan Abdul
authors.initials: SA
authors.lastname: Wanees Amin
mesh_terms: D000704:Analysis of Variance; D019412:Anatomy, Cross-Sectional; D001641:Bicuspid; D003646:Debridement / Q000295:instrumentation* / Q000379:methods; D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000033:anatomy & histology* / Q000601:surgery; D006801:Humans; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods*; D016369:Smear Layer; D018709:Statistics, Nonparametric