Preparation of Oval-shaped Root Canals in Mandibular Molars Using Nickel-Titanium Rotary Instruments: A Micro-computed Tomography Study

By Paqué F, Balmer M, Attin T, Peters OA

Date: 01/2010
Journal: JOE


Purpose: to evaluate the prepared surface areas of oval-shaped root canals in mandibular molars using different instrumentation techniques.

N= 48 mandibular molars (12/group)


  • Inclusion criteria: 1formaina in D root, canal ratio of more than 2, curvature less than 20.
  • Teeth were scanned by micro CT. instrumentation done by 1 operator.
  • H/CF: circumferential filing by hedstrom files to #40. (each file was moved at least twice).
  • 3 other groups used protaper universal to F4. PT/1:instrumented as 1 canal, PT/2: as 2 canals. PT/CH: circumferential. Post micro CT was taken and superimposed on the previous one.
  • After that PT/1: circumferential filling was done using hedstrom #30,#40.
  • After canal shaping was completed, canals were irrigated with a final sequence of 2.5% NaOCl, 17% EDTA, and 2.5% NaOCl (5 mL each).

Most highlighted Results:

  • There was no difference in volume after preparation among groups.
  • Unprepared area PT/1 (80%), PT/2 (60%)
  • No significant difference in the amount of unprepared root surface in the apical 4 mm.
  • Additional circumferential filing with hedstrom files in PT/1 decreased the fraction of unprepared to 69% .

Clinical Significance:

Well designed study, that showed that instrumenting the D canal as 2 canals would reduce the % of unprepared area.