Influence of Single Cone Techniques and Continuous Wave of Obturation on the resistance of Endodontic Cements union to Radicular Dentin

Endodontic obturation has the purpose to fill three-dimensional root canal system. The search for this objective resulted in the emergence of different techniques. The study proposed to evaluate, in vitro, the influence of Single Cone and Continuous Wave techniques on the adhesion of EndoSequence BC (Brasseler USA, Savannah, USA), Pulp Canal Sealer EWT (SybronEndo, Orange USA) and AH Plus (Dentsply , USA) to the dentinal walls of the root canals of extracted human teeth. Seventy-two human premolars were divided into 6 experimental groups (n = 12). The teeth were instrumented and obturated in a standardized way by means of the single cone technique or the continuous wave technique according to the specification of each group: a) EBC-OC Group: EndoSequence BC + Continuous Wave; B) PC-OC Group: Pulp Canal Sealer EWT + Continuous Wave; C) AH-OC Group: AH Plus + Continuous Wave; D) EBC-CU Group: EndoSequence BC + Single Cone; E) PC-CU Group: Pulp Canal Sealer EWT + Single Cone; F) AH-CU Group: AH Plus + Single Cone. The teeth were sectioned into approximately 1.0mm thick slices and the adhesion of the sealer to the dentin walls was measured using the push-out shear test. The failure mode was observed by visual inspection of a 12,5X magnification optics microscope. Data on union resistance by the group push-out test were submitted to statistical analysis by two-way ANOVA, post hoc and Mann-Whitney tests. There were no significant differences between the sealers when the Continuous Wave technique was employed (p=0,783); in the Single Cone technique the EndoSequence BC sealer had the highest bond strength, which was limited to the apical third, while the lowest bond strength values were attributed to the Pulp Canal Sealer EWT. The chi-square test revealed that the EndoSequence BC sealer showed an adhesive failure mode at the sealer/gutta percha interface in a proportion significantly higher than the Pulp Canal Sealer EWT, which, on the other hand, showed a predominance of adhesive failure mode at the dentin/sealer interface (p <0.05). The single cone technique showed better adhesion of the EndoSequence and AH Plus sealers when compared to the continuous wave technique.