title: Combined effects of nano-hydroxyapatite and Galla chinensis on remineralisation of initial enamel lesion in vitro.
abstract: OBJECTIVE
  The aim of the present study was to investigate the combined effects of nano-hydroxyapatite and Galla chinensis on remineralisation of initial enamel lesion.
  
  
  METHODS
  Bovine enamel blocks with in vitro produced initial lesion were used. The lesions were subjected to a pH-cycling regime for 12 days. Each daily cycle includes 4 x 3 min application with one of five treatments: NaF (positive control), deionised water (negative control), crude aqueous extract of G. chinensis (GCE), nano-hydroxyapatite (nano-HA) and GCE with nano-HA. The samples were subsequently evaluated using a microhardness tester, polarised light microscopy (PLM), X-ray diffraction (XRD) and scanning electron microscopy (SEM).
  
  
  RESULTS
  Surface hardness measurements and integrated mineral recovery value obtained from cross-sectional microhardness test (CSMH) revealed that all the treatment groups had significantly greater effect on enhancing remineralisation than that of the negative control group. Detailed investigation of both CSMH and PLM indicated that nano-HA would only help mineral deposition predominate in the outer layer of lesion and had limited capacity to reduce the lesion depth significantly. In GCE-nano-HA combined treatment group, more mineral deposition occurred in the lesion body and lesion depth was reduced significantly. Meanwhile, significantly greater mineral deposition in the outer portion of the lesion was also observed in comparison with GCE group. The results of XRD and SEM also showed that GCE could influence the deposition and adsorption of nano-HA.
  
  
  CONCLUSIONS
  There was a significant synergistic effect of combined GCE and nano-HA treatment on promoting the remineralisation of initial enamel lesion.
authors.affiliation: State Key Laboratory of Oral Diseases, Chengdu 610041, People's Republic of China.
authors.forename: Shengbin
authors.initials: S
authors.lastname: Huang
authors.forename: Shanshan
authors.initials: S
authors.lastname: Gao
authors.forename: Lei
authors.initials: L
authors.lastname: Cheng
authors.forename: Haiyang
authors.initials: H
authors.lastname: Yu
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000008:administration & dosage / Q000627:therapeutic use*; D002327:Cariostatic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D002417:Cattle; D003743:Dental Enamel / Q000187:drug effects* / Q000473:pathology; D004338:Drug Combinations; D004357:Drug Synergism; D004365:Drugs, Chinese Herbal / Q000008:administration & dosage / Q000627:therapeutic use*; D017886:Durapatite / Q000008:administration & dosage / Q000627:therapeutic use*; D006244:Hardness; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D008859:Microscopy, Polarization; D008903:Minerals / Q000032:analysis; D049329:Nanostructures / Q000008:administration & dosage / Q000627:therapeutic use*; D010936:Plant Extracts / Q000627:therapeutic use; D011897:Random Allocation; D012969:Sodium Fluoride / Q000627:therapeutic use; D013997:Time Factors; D017001:Tooth Demineralization / Q000473:pathology / Q000517:prevention & control*; D014089:Tooth Remineralization / Q000379:methods*; D014867:Water; D014961:X-Ray Diffraction
chemical_list: D001672:Biocompatible Materials; D002327:Cariostatic Agents; D004338:Drug Combinations; D004365:Drugs, Chinese Herbal; D008903:Minerals; D010936:Plant Extracts; D014867:Water; D012969:Sodium Fluoride; D017886:Durapatite