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Updated: Jun 29, 2026

Development of Amelogenin-chitosan Hydrogel for In Vitro Enamel Regrowth with a Dense Interface
Published on: July 10, 2014
Remineralising enamel caries with a novel peptide: An in vitro study
John Yun Niu1, Olivia Lili Zhang2, Iris Xiaoxue Yin2
1Faculty of Dentistry, The University of Hong Kong, Hong Kong, China; School of Dental Sciences, Newcastle University, Newcastle, UK.
Objective:
To evaluate the antibacterial and remineralising effects of GAPI peptide on artificial enamel caries.
Methods:
Human enamel blocks were exposed to Streptococcus mutans biofilm to create artificial carious lesions. The blocks were randomly assigned to either the GAPI treatment group or the deionised water control group, treated twice daily for 21 days. The viability, growth kinetics, and morphology of S. mutans biofilms were assessed using confocal laser scanning microscopy (CLSM), colony-forming unit (CFU) counting, and scanning electron microscopy (SEM). Lesion depth, mineral loss, calcium-to-phosphorus ratio, Knoop hardness, enamel surface morphology, and crystal characteristics of enamel lesions were determined using micro-computed tomography (Micro-CT), SEM-energy dispersive spectroscopy (EDS), a microhardness tester, SEM, and X-ray diffraction (XRD).
Results:
CLSM showed that the dead-to-live ratio of S. mutans was 0.8 ± 0.1 in the GAPI group and 0.4 ± 0.1 in the control group (p < 0.001). The Log CFUs were 6.9 ± 0.7 in the GAPI group and 8.1 ± 0.5 in the control group (p = 0.002). SEM revealed confluent growth of S. mutans in the control group but not in the GAPI group, which also exhibited cell damage. Micro-CT showed that the lesion depth (µm) was 142 ± 11 in the GAPI group and 178 ± 20 in the control group (p < 0.001), with mineral loss (gcm⁻³) of 1.1 ± 0.1 and 1.5 ± 0.1, respectively (p < 0.001). SEM-EDS indicated that the calcium-to-phosphorus ratio was 1.71 ± 0.02 in the GAPI group and 1.67 ± 0.03 in the control group (p = 0.006). Additionally, Knoop hardness was 302 ± 22 in the GAPI group and 242 ± 17 in the control group (p < 0.001). SEM revealed an orderly pattern of enamel rods in the GAPI group, and XRD showed better crystallisation of hydroxyapatite in the GAPI group compared to the control group.
Conclusion:
GAPI exhibits antibacterial and remineralising properties against artificial enamel caries.
Clinical Significance:
If the anti-caries properties of GAPI are confirmed in clinical studies, it could be used for caries prevention.
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