title: Influence of tooth-surface hydration conditions on optical coherence-tomography imaging.
abstract: OBJECTIVE
  This study examined the influence of tooth-surface hydration conditions on optical coherence tomography (OCT) imaging.
  
  
  METHODS
  Emitted light was coupled in a single-mode fibre-optic Michelson interferometer, and delivered to a sample and a reference mirror mounted on a linearly translating galvanometer driven by a triangular voltage waveform at a fringe-modulation frequency of 1kHz. Backscattered light from the sample was coupled back to the system, digitised and used to create two-dimensional images together with beam scanning. OCT imaging of the occlusal surfaces of 10 extracted human teeth was performed soon after mounting ('wet' condition), immediately after air blowing for 10s ('air-blow' condition), and at intervals thereafter ('1-min', '5-min' and '10-min' conditions, respectively).
  
  
  RESULTS
  For the wet condition, three distinct peaks indicated the water surface, tooth surface and dentino-enamel junction. Backscattered light was detected at levels above noise, possibly causing grainy OCT images. By contrast, two distinct peaks indicating the tooth surface and dentino-enamel junction were observed for the air-blow and 10-min conditions, with greater signal intensities for the latter. The intensity was lower for the air-blow condition than the wet condition. The signal intensities decreased during storage in air at room temperature.
  
  
  CONCLUSIONS
  Tooth-substrate hydration conditions thus appeared to influence time domain-OCT imaging.
authors: Department of Operative Dentistry, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-Ku, Tokyo 101-8310, Japan.
authors: Yutaka
authors: Y
authors: Shimamura
authors: Ryosuke
authors: R
authors: Murayama
authors: Hiroyasu
authors: H
authors: Kurokawa
authors: Masashi
authors: M
authors: Miyazaki
authors: Yukinori
authors: Y
authors: Mihata
authors: Shohei
authors: S
authors: Kmaguchi
mesh_terms: D000388:Air; D001718:Birefringence; D003743:Dental Enamel / Q000033:anatomy & histology; D003804:Dentin / Q000033:anatomy & histology; D003890:Desiccation; D004553:Electric Conductivity; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007368:Interferometry / Q000295:instrumentation; D008027:Light; D055100:Optical Fibers; D012542:Scattering, Radiation; D059629:Signal-To-Noise Ratio; D013696:Temperature; D013997:Time Factors; D041623:Tomography, Optical Coherence / Q000379:methods*; D014070:Tooth / Q000033:anatomy & histology*; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water