title: Enamel prism-like tissue regeneration using enamel matrix derivative.
abstract: BACKGROUND
  Enamel matrix derivative (EMD) has been shown to promote periodontal regeneration, but its effect on biomimetic mineralisation of enamel is not reported.
  
  
  OBJECTIVE
  This in vitro study aimed to investigate the effect of commercially available EMD on promoting biomimetic mineralisation in demineralised enamel using an agarose hydrogel model.
  
  
  METHODS
  Human enamel slices were demineralised with 37% phosphoric acid for 1 min. 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 96 h. 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.
  
  
  RESULTS
  SEM 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).
  
  
  CONCLUSIONS
  EMD promoted in vitro biomimetic mineralisation and facilitated enamel prism-like tissue formation on demineralised human enamel.
  
  
  CONCLUSIONS
  This study is the first to report on using EMD in biomimetic mineralisation, which may serve as a biomaterial for enamel repair.
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Hong Kong, China; Stomatologic Hospital & College, Anhui Medical University, Key Lab. of Oral Diseases Research of Anhui Province, Hefei, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Hong Kong, China.
authors.forename: May Lei
authors.initials: ML
authors.lastname: Mei
authors.affiliation: Stomatologic Hospital & College, Anhui Medical University, Key Lab. of Oral Diseases Research of Anhui Province, Hefei, China.
authors.forename: Quan-Li
authors.initials: QL
authors.lastname: Li
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Hong Kong, China.
authors.forename: Edward Chin Man
authors.initials: EC
authors.lastname: Lo
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Hong Kong, China. Electronic address: chchu@hku.hk.
authors.forename: Chun Hung
authors.initials: CH
authors.lastname: Chu
mesh_terms: D001031:Apatites / Q000032:analysis; D040761:Biomimetic Materials / Q000494:pharmacology*; D002122:Calcium Chloride / Q000737:chemistry; D003461:Crystallography; D003743:Dental Enamel / Q000737:chemistry / Q000187:drug effects* / Q000648:ultrastructure; D003746:Dental Enamel Proteins / Q000494:pharmacology*; D055119:Elastic Modulus; D005459:Fluorides / Q000737:chemistry; D006244:Hardness; D006801:Humans; D020100:Hydrogels / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010756:Phosphoric Acids / Q000009:adverse effects; D012038:Regeneration / Q000187:drug effects; D012685:Sepharose / Q000737:chemistry; D013052:Spectrometry, X-Ray Emission; D013696:Temperature; D013997:Time Factors; D017001:Tooth Demineralization / Q000139:chemically induced / Q000473:pathology; D014089:Tooth Remineralization / Q000379:methods*; D014961:X-Ray Diffraction
chemical_list: D001031:Apatites; D003746:Dental Enamel Proteins; D020100:Hydrogels; D010756:Phosphoric Acids; C109069:enamel matrix proteins; D012685:Sepharose; C030242:phosphoric acid; C025105:fluorapatite; D002122:Calcium Chloride; D005459:Fluorides
keywords: Biomimetic mineralisation; Emdogain; Enamel matrix derivative; Hydroxyapatite; Regeneration