Correlation between tug-back and cone fitness in curved root canals prepared with reciprocating files

Abstract

Objectives. The purpose of this study was to compare the gutta-percha-occupied area (GPOA) of two gutta-percha cones with different size and taper using micro-computed tomographic (micro-CT) imaging and to evaluate the relationship between GPOA and tug-back in curved root canals instrumented with reciprocating files. Methods. Twenty curved roots from extracted human maxillary and mandibular molars were divided into two groups. In group R (n = 10), root canals were prepared with Reciproc R25 files (VDW, Munich, Germany) and in group W (n = 10), root canals were prepared using WaveOne Primary files (Dentsply Maillefer, Ballaigues, Switzerland). The presence or absence of tug-back was decided for both of #25/.08 and #30/.06 gutta-percha cones in every root canal. Micro-CT imaging was used to analyze cone fitness by calculating the percentage of GPOA at 1-, 2-, and 3-mm levels from the working length. The correlation between the sum of the GPOA from all three levels and the presence of tug-back was also investigated. The data were analyzed statistically. The level of significance was set at 5%.

Results. Tug-back was present in 45% and 100% root canals for #25/.08 and #30/.06 cones, respectively, with a significant difference (P < .05). At the 2- and 3-mm levels, #30/.06 cones produced significantly higher GPOA in both group R and W (P < .05). The sum of the GPOA score was significantly higher in the samples with tug-back than in those without tug-back (88.12% ± 12.17% vs. 75.35% ± 13.42%

P < .05)

however, there was no significant difference between the two cone types for this correlation (P > .05).

Conclusion. Under the conditions of this study, tug-back can be a definitive determinant for indicating higher cone fitness in the curved root canal prepared with reciprocating files regardless of the cone type.