title: Effects of gallic acid on the morphology and growth of hydroxyapatite crystals.
abstract: OBJECTIVE
  This study was designed to explore the effect of gallic acid (GA, one of the ingredients of chemical compounds from galla chinensis) on the morphology and growth of hydroxyapatite crystals.
  
  
  METHODS
  The crystals was produced by mixing CaCl2 and KH2PO4 with or without GA (4g/L) at room temperature for 3, 12, 24h and 3, 7, 14 days. Subsequently, the micro-structure, morphology and composition of the crystals were investigated via SEM, XRD, ATR-FTIR and fluorescence microscopy.
  
  
  RESULTS
  The mineral phase was hydroxyapatite in both groups after 14 days, but their processes and the morphology were completely different. The crystals from groups utilizing GA for 14 days were urchin-like, while loose needle-like crystals were observed in groups without GA. XRD results indicated that GA might limit the growth of the crystals, mainly on the 002 direction. The results of ATR-FTIR and fluorescence microscopy revealed that the unique structures might caused by the participation of GA during crystals formation.
  
  
  CONCLUSIONS
  GA might affect and participate into the formation of the hydroxyapatite, and regulate the morphology and structure of the crystals, to enhance the remineralization process.
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Endodontics and Operative Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
authors.forename: Bei
authors.initials: B
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Endodontics and Operative Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
authors.forename: He
authors.initials: H
authors.lastname: Yuan
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Endodontics and Operative Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Endodontics and Operative Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
authors.forename: Xuedong
authors.initials: X
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Endodontics and Operative Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
authors.forename: Xuelian
authors.initials: X
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Endodontics and Operative Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China. Electronic address: tang_bei@hotmail.com.
authors.forename: Jiyao
authors.initials: J
authors.lastname: Li
mesh_terms: D003460:Crystallization; D003743:Dental Enamel / Q000187:drug effects; D004365:Drugs, Chinese Herbal / Q000737:chemistry; D017886:Durapatite / Q000737:chemistry*; D005707:Gallic Acid / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared; D014089:Tooth Remineralization / Q000379:methods; D014961:X-Ray Diffraction
chemical_list: D004365:Drugs, Chinese Herbal; D005707:Gallic Acid; D017886:Durapatite
keywords: Auto-fluorescence; Gallic acid; Hydroxyapatite crystal; Morphology