title: Disruption of enamel crystal formation quantified by synchrotron microdiffraction.
abstract: OBJECTIVE
  To understand the pathology of the ultrastructure of enamel affected by systemic disorders which disrupt enamel tissue formation in order to give insight into the precise mechanisms of matrix-mediated biomineralization in dental enamel in health and disease.
  
  
  METHODS
  Two-dimensional synchrotron X-ray diffraction has been utilized as a sophisticated and useful technique to spatially quantify preferred orientation in mineralized healthy deciduous dental enamel, and the disrupted crystallite organization in enamel affected by a systemic disease affecting bone and dental mineralization (mucopolysaccharidosis Type IVA and Type II are used as examples). The lattice spacing of the hydroxyapatite phase, the crystallite size and aspect ratio, and the quantified preferred orientation of crystallites across whole intact tooth sections, have been determined using synchrotron microdiffraction.
  
  
  RESULTS
  Significant differences in mineral crystallite orientation distribution of affected enamel have been observed compared to healthy mineralized tissue. The gradation of enamel crystal orientation seen in healthy tissue is absent in the affected enamel, indicating a continual disruption in the crystallite alignment during mineral formation.
  
  
  CONCLUSIONS
  This state of the art technique has the potential to provide a unique insight into the mechanisms leading to deranged enamel formation in a wide range of disease states.
  
  
  CONCLUSIONS
  Characterising crystal orientation patterns and geometry in health and following disruption can be a powerful tool in advancing our overall understanding of mechanisms leading to the tissue phenotypes seen clinically. Findings can be used to inform the appropriate dental management of these tissues and/or to investigate the influence of therapeutic interventions or external stressors which may impact on amelogenesis.
authors.affiliation: Queen Mary University London, Barts and the London School of Medicine and Dentistry, Institute of Dentistry, London E1 4NS, UK. m.al-jawad@qmul.ac.uk
authors.forename: Maisoon
authors.initials: M
authors.lastname: Al-Jawad
authors.forename: Owen
authors.initials: O
authors.lastname: Addison
authors.forename: Malik Arshman
authors.initials: MA
authors.lastname: Khan
authors.forename: Alison
authors.initials: A
authors.lastname: James
authors.forename: Christian J
authors.initials: CJ
authors.lastname: Hendriksz
mesh_terms: D000465:Algorithms; D016880:Anisotropy; D018360:Crystallography, X-Ray / Q000379:methods; D003743:Dental Enamel / Q000737:chemistry / Q000648:ultrastructure*; D003804:Dentin / Q000737:chemistry / Q000648:ultrastructure; D017886:Durapatite / Q000737:chemistry; D006801:Humans; D007180:Incisor / Q000737:chemistry / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D016532:Mucopolysaccharidosis II / Q000378:metabolism / Q000473:pathology; D009085:Mucopolysaccharidosis IV / Q000378:metabolism / Q000473:pathology; D053838:Scattering, Small Angle; D017356:Synchrotrons; D014074:Tooth Calcification; D014094:Tooth, Deciduous / Q000737:chemistry / Q000648:ultrastructure*
chemical_list: D017886:Durapatite