title: Enamel diffusion modulated by Er:YAG laser (Part 2). Organic matrix.
abstract: Organic matrix (OM) has been hypothesized as a key player in the laser-induced retardation of enamel diffusion (LRED).
  
  
  OBJECTIVE
  Therefore, this study was aimed to quantify the contribution of OM in LRED.
  
  
  METHODS
  Four groups of enamel sections (n=10) were assigned to 'normal', 'laser treated', 'OM extracted' and 'laser+OM extraction' groups for measurement of diffusion coefficient (DC) using fluorescence recovery after photobleaching (FRAP) and fluorophores transport study (FTS). Er:YAG laser treatment and OM extraction were performed on respective groups. Sections were characterized with stereomicroscopy and polarized light microscopy. Treatment effects were statistically assessed with a factorial ANOVA.
  
  
  RESULTS
  DC measured by FRAP and FTS coupled with confocal microscopy revealed the significant effect of OM (p=0.001) and laser treatment (p<0.01). After OM extraction, the laser effect on diffusion decreased about 34-75%, confirming the significant role of OM in LRED.
  
  
  CONCLUSIONS
  Both FRAP and FTS may be promising tools to quantify enamel DC.
authors.affiliation: Department of Preventive Dentistry, Faculty of Dentistry, 5 Lower Kent Ridge Road, National University of Singapore, Singapore 119074.
authors.forename: N L
authors.initials: NL
authors.lastname: Maung
authors.forename: T
authors.initials: T
authors.lastname: Wohland
authors.forename: C-Y S
authors.initials: CY
authors.lastname: Hsu
mesh_terms: D000465:Algorithms; D000704:Analysis of Variance; D003743:Dental Enamel / Q000737:chemistry / Q000528:radiation effects* / Q000648:ultrastructure; D005453:Fluorescence; D006801:Humans; D053685:Laser Therapy / Q000379:methods*; D053844:Lasers, Solid-State / Q000627:therapeutic use*