A non-discoloring bioactive hydrogel for caries management: an in vitro study
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Updated: May 16, 2026
Development of Amelogenin-chitosan Hydrogel for In Vitro Enamel Regrowth with a Dense Interface
Published on: July 10, 2014
Iris Xiaoxue Yin1, Veronica Ruiyu Ma1, Chun Hung Chu1
1Faculty of Dentistry, University of Hong Kong, 34 Hospital Road, Hong Kong Special Administrative Regions of China.
Objective:
To develop a novel anti-caries hydrogel with non-discolouring, antibacterial and mineralising properties.
Method:
The fCS/nSPS hydrogel was developed by incorporating nano strontium phosphosilicate (nSPS) into a functionalised chitosan (fCS) matrix, followed by ultraviolet-induced photocrosslinking. The hydrogel's phase formation and composition were identified by X-ray Diffraction spectroscopy (XRD), whereas its functional groups were detected by Fourier Transform Infrared spectroscopy (FTIR). Surface morphology was observed by Scanning Electron Microscopy (SEM). Antibacterial effects of fCS/nSPS were evaluated using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Mineralising properties were studied using SEM and XRD on fCS/nSPS-treated dentine blocks after cariogenic challenge. Cytocompatibility of fCS/nSPS-treated dentine was tested towards human gingival fibroblasts (HGF-1). Dentine discolouration after intervention (ΔE) was quantified using colour spectrophotometry. Silver diamine fluoride (SDF) and deionised water were used as controls.
Results:
NMR, XRD, FTIR, and SEM confirmed the synthesis of fCS/nSPS. The MIC/MBC values (mean±SD) of fCS/nSPS against Streptococcus mutans, Actinomyces naeslundii, and Lactobacillus acidophilus are 87±20/200±35, 129±38/373±80, and 110±36/253±53 µg/mL, respectively. SEM revealed a smooth mineralised surface on fCS/nSPS-treated dentine. XRD confirmed deposition of strontium phosphosilicate. HGF-1 viability (mean ± SD) of fCS/nSPS, SDF and Water group were 135.7±4.9 %, 0.5±0.1 % and 131.7±3.5 % (p < 0.001, SDF
Conclusion:
The developed fCS/nSPS hydrogel did not cause significant tooth discolouration, exhibited antibacterial activity, promoted dentine's surface mineral deposition, and was cytocompatible. These properties support further investigation of this material for non‑restorative caries management.
