Effect of allicin-incorporated graphene oxide hydrogel on dentin microhardness

The success of root canal treatment and regenerative endodontics relies on thorough disinfection and dentin integrity preservation to ensure long-term tooth survival. This study evaluates the pH stability, material characteristics, microhardness and antimicrobial effects of an allicin-incorporated GO-AgNP hydrogel compared to conventional intracanal medicaments.

An allicin-incorporated GO-AgNP hydrogel was synthesized using allicin extract, GO-AgNPs, and sodium alginate. Characterization was performed via FTIR, SEM, and EDX. pH stability of AllGOAgNP, CaOH, CHX, and TAP was assessed at 5 min, 24 h, and 7 days using a digital pH meter. A total of 120 extracted human premolars were randomly assigned to four groups: (1) Control, (2) CaOH, (3) TAP, and (4) AllGOAgNP. Medicaments were applied and incubated at 37 °C with 100% humidity for 1 week, 1 month, and 3 months. Dentin microhardness was evaluated using a Vickers microhardness tester before and after treatment across the coronal, middle, and apical thirds. Additionally, antimicrobial efficacy against E. faecalis and C. albicans was assessed using the disc diffusion method, with inhibition zones measured for each medicament. Statistical analysis was performed using one-way ANOVA and Tukey's post-hoc test (p < 0.05).

FTIR analysis confirmed the successful incorporation of allicin, GO, AgNPs, and sodium alginate. SEM images showed a uniform nanoparticle distribution in the hydrogel, and EDX confirmed the presence of key elements, including silver and sulfur. The Allicin-GO-AgNP hydrogel maintained a near-neutral pH (mean 7.083), while CaOH (mean 12.297) and TAP (mean 12.683) exhibited highly alkaline pH levels. ANOVA results demonstrated significant differences in microhardness across groups and regions (p < 0.05). The Allicin-GO-AgNP hydrogel exhibited significantly higher microhardness than CaOH and TAP across all regions (p < 0.001), with no significant difference from the control in the coronal and middle thirds (p > 0.05). SEM-EDX analysis of treated dentin confirmed minimal structural alterations in the Allicin-GO-AgNP hydrogel group compared to the control. In antimicrobial testing, the hydrogel demonstrated moderate efficacy with inhibition zones of 20 mm against E. faecalis and 13 mm against C. albicans, outperforming calcium hydroxide after 24 h.

The Allicin-GO-AgNP hydrogel demonstrated superior dentin preservation compared to conventional intracanal medicaments. Its near-neutral pH, structural stability, and microhardness retention make it a promising alternative for endodontic applications, particularly in regenerative endodontics. Future studies should focus on its long-term biocompatibility and antimicrobial effectiveness in clinical settings.

The Allicin-GO-AgNP hydrogel preserves dentin integrity better than conventional medicaments, reducing the risk of structural weakening. Its near-neutral pH minimizes collagen degradation, making it a promising option for regenerative endodontics. This novel hydrogel offers a biocompatible alternative with potential long-term clinical benefits.