Cannabinoid-Functionalized Glass Ionomer Cements: Structural Stability, Fluoride Release, and Antibiofilm Activity against Cariogenic Bacteria

Abstract

Dental caries is strongly associated with biofilm-forming bacteria such as Streptococcus mutans and Lactobacillus acidophilus, and improving the antimicrobial performance of restorative materials remains a major challenge in preventive dentistry. Glass ionomer cements (GICs) exhibit favorable properties including chemical adhesion and fluoride release, yet their intrinsic antibacterial activity remains limited. This study investigated the incorporation of four cannabinoid-rich fractions (F1, F2, F3, and F4) into glass ionomer cements and evaluated their structural, antimicrobial, and biological properties. Cannabinoid fractions isolated from hemp flowers were incorporated into Ketac Cem Radiopaque and Ketac Molar Easymix formulations at 1 wt %. Data were analyzed using one-way ANOVA, Tukey’s post hoc test, and Kruskal–Wallis analysis (p < 0.05). Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and X-ray diffraction (XRD) analyses demonstrated structural compatibility between the cannabinoid fractions and the glass ionomer matrix, indicating preservation of the original phase composition and the absence of disruption in the acid–base setting reaction. The modified cements exhibited strain-dependent antibacterial and antibiofilm activity, with KCR-F4 showing the strongest reduction in S. mutans viability (47.35%) and KME-F1 demonstrating the greatest activity against L. acidophilus (14.77%). Significant differences were observed among GIC types and cannabinoid fractions for antimicrobial activity, fluoride release, and cytotoxicity. Scanning electron microscopy (SEM) imaging further confirmed decreased bacterial adhesion and disrupted surface colonization on cannabinoid-modified cement surfaces. Fluoride-release behavior was largely preserved following cannabinoid incorporation. However, cytotoxicity analysis revealed increased LDH release at the tested concentration, indicating a cytotoxicity trade-off associated with enhanced antimicrobial activity. It is concluded that cannabinoid extract is promising as an additive to formulate bioactive glass-ionomer cements, although further optimization is required to balance antimicrobial efficacy with cytocompatibility.