Comparison of centering ability of three different endodontic instruments using cone-beam computed tomography: An in vitro study

Aim: Centering ability of an instrument is the ability of the instrument to act centrally inside the canal without deflections. This property is of significance in assessment of any endodontic file because endodontic accidents due to instrumentation, commonly apical transportation can be avoided in case of a perfectly centered instrument. Therefore, the aim of the present study was to compare three different endodontic files, K File, Hand ProTaper, and Rotary ProTaper for their centering ability using cone-beam computed tomography (CBCT). Materials and methods: On 30 extracted mandibular premolars, 3 reference lines were created from the apex. Preoperative CBCT images were made and analyzed. D₁ and D₂ are the centering ratios measured buccolingually and mesiodistally, following which the samples were randomly allotted to one of the three groups (K File, Hand ProTaper, and Rotary ProTaper) for instrumentation. Postoperative images were obtained and canal dimensions were assessed. The differences were calculated and the centering ability was determined using the centering ratio formula. Comparison was done using ANOVA test. Results: The mean working length of all the samples was 20.8 mm. The average preoperative D₁ and D₂ values obtained were 0.0067 and 0.0117, respectively. Following instrumentation, the obtained D₁ and D₂ values in group I, group II, and group III were 0.0048 and 1.07, 0.783 and 1.24, and 0.785 and 0.96, respectively. Intergroup comparison showed insignificant p value (p > 0.05). Conclusion: K File, Hand ProTaper, and Rotary ProTaper were equally efficient to act centrally in straight canals. Clinical significance: Centering ability of an instrument is of significance in avoiding accidents such as canal transportation. K File, Hand ProTaper, and Rotary ProTaper were found to be equally efficient to act centrally in straight canals.