Effect of graphene-based intracanal medicament on push-out bond strength of different endodontic sealers in root canal dentin - an in vitro study.

Abstract

Introduction: Graphene-based hydrogels incorporating antimicrobial agents, such as allicin and silver nanoparticles, offer potential therapeutic benefits. This study aimed to evaluate the effect of an allicin-incorporated graphene oxide-silver nanoparticle hydrogel on the push-out bond strength of endodontic sealers and the influence of different removal protocols.

Materials and methods: A total of 60 extracted human single-rooted teeth were prepared to F3 size protaper and irrigated with 3% sodium hypochlorite and 17% Ethylenediaminetetraacetic Acid (EDTA) The experimental hydrogel (allicin + graphene oxide + silver nanoparticles in 2% sodium alginate base) was placed in all canals and incubated for 7 days. Specimens were randomised by sealer type (AH Plus, Mineral Trioxide Aggregate (MTA) Fillapex, Sealapex) and removal protocol: syringe irrigation, passive ultrasonic irrigation (PUI), or XP-Endo Finisher activation. Push-out bond strength was measured using a universal testing machine. A subset of specimens (n = 3 per protocol) underwent Scanning Electron Microscopy (SEM)/Energy Dispersive X-ray Spectroscopy (EDX) analysis to evaluate residual medicament. Data were statistically analysed.

Results: Push-out bond strength was significantly influenced by both sealer type and removal protocol (p < 0.05). AH Plus exhibited the highest bond strength (mean ± standard deviation [SD]: 5.2 ± 1.4 MPa), followed by Sealapex (1.9 ± 0.3 MPa) and MTA Fillapex (1.5 ± 0.4 MPa). Activation-assisted protocols (PUI: 4.8 ± 1.2 MPa; XP-Endo Finisher: 5.0 ± 1.3 MPa) significantly increased bond strength compared to syringe irrigation alone (3.1 ± 1.0 MPa; p < 0.05). SEM/EDX analysis revealed minimal residual hydrogel after activation, without adversely affecting sealer adhesion. Bond strength was highest in the cervical third and lowest in the apical third (p < 0.05).

Conclusion: The allicin-incorporated graphene oxide-silver nanoparticle hydrogel did not compromise the push-out bond strength of the evaluated endodontic sealers when appropriate medicament removal protocols were employed. PUI and XP-Endo Finisher activation effectively facilitated hydrogel removal and maintained sealer adhesion, supporting the potential use of this material as an intracanal medicament.