Micro-CT Study of Shaping Behavior of ProTaper Ultimate, TruNatomy and Reciprocating WaveOne Gold in Severely Curved...

To analyze the canal transportation and centering ability of rotary, ProTaper Ultimate (PTU) and TruNatomy (TRN), and reciprocating WaveOne Gold (WOG) instrumentation systems in curved root canals.

Forty-two upper human molars with curved mesiobuccal canals (30°-40°) were selected. The samples were assigned into 3 groups based on the instruments used: Group 1. PTU up to F2, 25/08; Group 2. TRN Primary file 26/04; Group 3. WOG Primary file 25/07. For irrigation, 3% sodium hypochlorite (NaOCl) was used throughout the instrumentation. Final irrigation protocol included 3% NaOCl, followed by 15% ethylenediaminetetraacetic acid and NaOCl. Each sample was scanned by micro-computed tomography (μCT) before and after the chemomechanical instrumentation. On μCT scans, the canal transportation and centring ability of the instrumentation systems were calculated at the levels of 3, 5, and 7 mm from the apex. Analysis of variance with Bonferroni test were used for the statistical analysis with the P value set at 0.05.

There were no significant differences between the instrumentation systems regarding their centering ability and transportation (P > .05). PTU showed significantly better centering in the coronal third (mean 0.595 mm) compared with WOG (mean 0.329 mm; P = .035). Regarding canal transportation at different canal levels, no significant difference between the groups was found (P > .05).

All tested instrumentation systems showed similar canal transportation, with one exception; PTU showed better centring ability in the coronal third. The study confirmed that different manufacturing and design features, if properly combined, may all result in valid operative sequence and proper shaping.