title: Physical and chemical characterization of dentin surface following treatment with NovaMin technology.
abstract: OBJECTIVE
  The aim of this study was to characterize, in vitro, the mode of action of calcium sodium phosphosilicate (NovaMin) in occluding dentin tubules for the purpose of treating dentin hypersensitivity.
  
  
  METHODS
  Calcium sodium phosphosilicate (CSPS) was combined with artificial saliva on surfaces of prepared dentin discs. The layer formed was initially examined by a scanning electron microscope (SEM). Focused ion beam (FIB) milling was used to make bulk cross-sections and thin film lamellae. Low kV scanning transmission electron microscopy (STEM), energy dispersive x-ray spectroscopy (EDS), and selected area electron diffraction were then used to characterize, chemically and structurally, the layer formed and the material occluding the tubules. Experiments were also performed to assess the suitability of using an environmental scanning electron microscope (ESEM) in wet mode to follow the transition from CSPS to hydroxyapatite.
  
  
  RESULTS
  SEM imaging showed that a layer was formed on the treated dentin samples, and that this layer occluded tubules. Chemical and structural analysis of this material showed that it was hydroxyapatite-like. The wet mode ESEM experiments demonstrated that this technique has the potential to follow the transition from CSPS to the crystalline hydroxyapatite material.
  
  
  CONCLUSIONS
  The use of modern imaging and analysis techniques has demonstrated, in vitro, the reaction of CSPS from an amorphous material to a crystalline hydroxyapatite-like material. These experiments confirmed an occlusion mode of action for CSPS for the treatment of dentin hypersensitivity.
authors: GlaxoSmithKline, Consumer Healthcare Weybridge, Surrey, UK. jonathan.s.earl@gsk.com
authors: J S
authors: JS
authors: Earl
authors: R K
authors: RK
authors: Leary
authors: K H
authors: KH
authors: Muller
authors: R M
authors: RM
authors: Langford
authors: D C
authors: DC
authors: Greenspan
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D002130:Calcium Phosphates / Q000737:chemistry / Q000494:pharmacology; D019343:Citric Acid / Q000737:chemistry; D003461:Crystallography; D003804:Dentin / Q000737:chemistry / Q000187:drug effects* / Q000648:ultrastructure; D057133:Dentin Desensitizing Agents / Q000737:chemistry / Q000494:pharmacology*; D003807:Dentin Sensitivity / Q000188:drug therapy*; D017886:Durapatite / Q000737:chemistry; D005898:Glass / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D017348:Microscopy, Electron, Scanning Transmission; D010316:Particle Size; D012464:Saliva, Artificial / Q000737:chemistry; D017640:Silicates / Q000737:chemistry / Q000494:pharmacology; D013052:Spectrometry, X-Ray Emission; D013997:Time Factors
chemical_list: D002130:Calcium Phosphates; D057133:Dentin Desensitizing Agents; C510984:NovaMin; D012464:Saliva, Artificial; D017640:Silicates; D019343:Citric Acid; C076375:rhenanite; D017886:Durapatite