Influence of different obturation techniques on the bond strength of the filling material to the root canal dentin and the quality of the final obturation

Aim: This study aimed to evaluate the influence of different obturation techniques on the bond strength (BS) of the filling material to the root canal dentin and the quality of the final obturation. Methodology: Forty mandibular premolars extracted from human had their root canals prepared, irrigated, dried, and distributed into four groups, according to the obturation technique performed (n=10): Lateral compaction (G(LC)); Single-cone (G(SC)); Tagger's hybrid (G(TH)); and Continuous wave condensation (G(CW)). Radiographic images were obtained and assessed before and after the obturation procedures. Afterward, roots were transversally sectioned in 1-mm slices and analyzed regarding the obturation quality, followed by push-out test and failure mode analysis. Data were statistically analyzed by 2-way ANOVA and post-hoc Tukey test; and by Kruskal-Wallis and post-hoc Games-Howell and Sidak tests. Results: All groups presented highest BS mean values in the apical third (p<0.05). Regardless of the root third, G(CW) had the lowest BS values (p<0.05). Radiographically, G(LC) presented higher number of failures compared to G(TH) and G(CW) (p<0.05); and G(TH) showed higher values of overfilling (p<0.05). For the stereomicroscope analysis, G(TH) had the largest filled area, while G(LC) (p=0.001) presented the smallest sealed area. Conclusions: The different obturation techniques of the root canal influenced the quality and BS of the filling material to the root dentin. Tagger's hybrid technique showed the best filling quality, with a larger filling area, however it presented a greater amount of overfilling. The continuous wave condensation technique provided less adhesion between the filling material and the root canal dentin.