RESUMO
Aims The aim of this study was to evaluate the degree of tug-back after root canal preparation with respect to the gutta-percha-occupied area (GPOA). Materials and Methods Roots of 50 mandibular premolar teeth were prepared till size 35/0.04, then gutta-percha (GP) cones of same size and taper were adapted to root canals, and the degree of tug-back sensation was scored as loose, slight, adequate and strong. Root canals were filled with GP and AH26 sealer, and then sectioned horizontally 1 mm from the apical end at three levels. GPOA and its sum from the three levels sum of GPOA (sGPOA%) were calculated using stereomicroscope. Statistical Analysis At each sectioned level, GPOA% was compared with the score of tug-back sensation using one-way ANOVA [Analysis of variance] at a 5% significance level. Multiple pair wise comparisons were performed using Tukey test. Results Tug-back sensation was present in all canals, described as slight, adequate and strong in 4, 8 and 8 canals, respectively. Among the tug-back scores, quantitative analyses of GPOA% showed significant differences at 1-and 2-mm levels. The strong tug-back with sGPOA of 76.5 ± 11.1% was significantly higher than that of slight tug-back. Conclusions Under the conditions of this study, the tug-back scoring system can be applied to determine the amount of GP adaptation inside the root canal.