Enamel prism-like tissue regeneration using enamel matrix derivative

Abstract

BackgroundsEnamel matrix derivative (EMD) has been shown to promote periodontal regeneration, but its effect on biomimetic mineralisation of enamel is not reported. ObjectivesThis in vitro study aimed to investigate the effect of commercially available EMD on promoting biomimetic mineralisation in demineralised enamel using an agarose hydrogel model. MethodsHuman enamel slices were demineralised with 37% phosphoric acid for 1min. They were covered with a 2-mm-thick EMD-calcium chloride (CaCl2) agarose hydrogel. Another 2-mm-thick ion-free agarose hydrogel was added on top of the EMD-CaCl2 hydrogel. They were incubated in a phosphate solution containing fluoride at 37°C for 96h. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) were used to evaluate the crystals formed on the demineralised enamel surface. A nano-indenter was used to evaluate the elastic modulus and nanohardness on the surface of the enamel slices. ResultsSEM observed enamel prism-like crystals formed on the enamel. They had typical apatite hexagonal structures, which corroborated the enamel's microstructure. EDX revealed that the elements were predominantly calcium, phosphorus, and fluorine. XRD confirmed that they were fluorinated hydroxyapatite. The mean elastic modulus before and after remineralisation was 59.1GPa and 78.5GPa (p<0.001), respectively; the mean nanohardness was 1.1GPa and 2.2GPa, respectively (p<0.001). ConclusionsEMD promoted in vitro biomimetic mineralisation and facilitated enamel prism-like tissue formation on demineralised human enamel. Clinical significanceThis study is the first to report on using EMD in biomimetic mineralisation, which may serve as a biomaterial for enamel repair.