title: The deposition and imaging of silica sub-micron particles in dentine.
abstract: OBJECTIVE
  Sub-micron particles may assist in the delivery of compounds into dentine tubules. The surface interactions of the particles with dentine may prevent them from entering the tubules. The aim of this study is to investigate whether silica particles, treated with surfactants improves dentine tubules occlusion using both artificial and human tooth models
  
  
  METHODS
  Spherical silica particles (size 130-810nm) bearing an encapsulated ruthenium luminescent complex were coated with the following surfactants: Zonyl(®) FSA, Triton(®) X-100 and Tween20(®). The particles were prepared as 0.004% w/v and 0.04% w/v solutions with deionized water and were applied to the surface of; (1) in vitro model of PET ThinCert™ cell culture inserts; (2) 0.1mm thick sections of human molar teeth.
  
  
  RESULTS
  Scanning electron and confocal fluorescence microscopy images show that particles without any coating and with TritonX-100 coating had the highest aggregation. Particles with Tween-20 are less aggregated on the surface and show inclusion in the tubules. Particles coated with fluorosurfactant Zonyl show a preference for aggregation at the tubule. With the ThinCert™ membranes high aggregation within the artificial tubules was increased by particle concentration.
  
  
  CONCLUSIONS
  The use of silica sub-micron particles on hard dental tissues is dependent on the modification of the surface chemistry of both the particle and the dentine and the employment of the fluorοsurfactant may improve tubule occlusion. The use of ThinCerts™ membrane is useful in vitro model to mimic dentinal tubules and observe the ability of particles to occlude small channels.
  
  
  CONCLUSIONS
  The use of silica sub-micron particles on hard dentine tissues is dependent on the modification of the surface coating of the particles. This may influence how particles are incorporated in potential delivery vehicles applied to the dentine surface with the employment of a fluorosurfactant showing promise.
authors.affiliation: Physical Sciences of Imaging in the Biological Sciences, University of Birmingham, Birmingham B15 2TT, United Kingdom.
authors.forename: Sunil
authors.initials: S
authors.lastname: Claire
authors.affiliation: School of Dentistry, University of Birmingham, Birmingham, B15 2TT, United Kingdom. Electronic address: a.d.walmsley@bham.ac.uk.
authors.forename: Anthony Damien
authors.initials: AD
authors.lastname: Walmsley
authors.affiliation: Physical Sciences of Imaging in the Biological Sciences, University of Birmingham, Birmingham B15 2TT, United Kingdom.
authors.forename: Sophie
authors.initials: S
authors.lastname: Glinton
authors.affiliation: Physical Sciences of Imaging in the Biological Sciences, University of Birmingham, Birmingham B15 2TT, United Kingdom.
authors.forename: Hayley
authors.initials: H
authors.lastname: Floyd
authors.affiliation: School of Dentistry, University of Birmingham, Birmingham, B15 2TT, United Kingdom.
authors.forename: Rachel
authors.initials: R
authors.lastname: Sammons
authors.affiliation: School of Chemistry, University of Birmingham, Birmingham, B15 2TT, United Kingdom.
authors.forename: Zoe
authors.initials: Z
authors.lastname: Pikramenou
mesh_terms: D001696:Biomechanical Phenomena; D002478:Cells, Cultured; D003766:Dental Occlusion; D003804:Dentin / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D008963:Molar / Q000166:cytology; D009930:Organic Chemicals / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry; D014092:Tooth Root / Q000187:drug effects / Q000648:ultrastructure; D014867:Water / Q000737:chemistry
chemical_list: D009930:Organic Chemicals; D013501:Surface-Active Agents; D014867:Water; C038646:Zonyl; D012822:Silicon Dioxide
keywords: Dentinal tubules; Dentine; Microscopy; Sub-micron particles; Surface coating; Surfactants