Evaluation of the interaction between sodium hypochlorite and several formulations containing chlorhexidine and its effect on the radicular dentin—SEM and push‐out bond strength analysis

Abstract

The aim of the current study was to evaluate the presence of debris and smear layer after endodontic irrigation with different formulations of 2% chlorhexidine gluconate (CHX) and its effects on the push-out bond strength of an epoxy-based sealer on the radicular dentin. One hundred extracted human canines were prepared to F5 instrument and irrigated with 2.5% sodium hypochlorite and 17% ethylenediaminetetraacetic acid. Fifty teeth were divided into five groups (n = 10), according to the final irrigation protocol with different 2% CHX formulations: G1 (control, no final rinse irrigation), G2 (CHX solution), G3 (CHX gel), G4 (Concepsis), and G5 (CHX Plus). In sequence, the specimens were submitted to scanning electron microscopy (SEM) analysis, in the cervical-medium and medium-apical segments, to evaluate the presence of debris and smear layer. The other 50 teeth were treated equally to a SEM study, but with the root canals filled with an epoxy-based endodontic sealer and submitted to a push-out bond strength test, in the cervical, middle, and apical thirds. G2, G3, G4, and G5 provided higher precipitation of the debris and smear layer than G1 (P < 0.05), but these groups were similar to each other (P > 0.05), in both segments. The values obtained in the push out test did not differ between groups, independent of the radicular third (P > 0.05). The CHXs formulations caused precipitation of the debris and smear layer on the radicular dentin, but these residues did not interfere in the push-out bond strength of the epoxy-based sealer.

Effectiveness of several solutions to prevent the formation of precipitate due to the interaction between sodium hypochlorite and chlorhexidine and its effect on bond strength of an epoxy‐based sealer

“…, Graziele Magro et al . ). However, the chemical composition of this precipitate is questionable because through nuclear magnetic resonance spectroscopy analysis, it has been observed that a mixture of NaOCl and chlorhexidine acetate does not produce PCA (Thomas & Sem ).…”

Consequences of chemical residue formation during potentiation of final irrigation

“…The length was standardized at 15 mm using an Isomet cutting machine (Isomet 1000, Buehler Ltd, Lake Bluff, IL, USA) with a diamond disc at 250 revolutions per minute (rpm), under irrigation, reducing the height of the tooth crown and gaining access to the canal 18 . The patency was performed by inserting a # 15 K file (Dentsply, Maillefer, Ballaigues, Switzerland) until the tip of the instrument was seen juxtaposed to the apical foramen 19,20 . Soon after, 1mm was subtracted from this measurement, obtaining a working length of 14mm.…”

“…The root apex of each specimen was closed with pink wax # 7, avoiding the extrusion of irrigants 20,21 . The specimens were inserted into a sterile metallic device and adjusted until they were firm.…”

Dentin Bond Strength Evaluation of Three Root Canal Sealers with Cold Gutta-Percha Lateral Obturation Technique: Push-Out Test Study

“…All specimens were kept moist by keeping them in gauze moistened with sterile saline solution, and were incubated for 7 days at 37 o C with 100% humidity (12) .…”