title: Laser light transmission in teeth: a study of the patterns in different species.
abstract: OBJECTIVE
  The aim of this study was to investigate the pattern of light transmission through teeth of different species and to examine laser light propagation within enamel from various animal sources.
  
  
  METHODS
  Sectioned teeth from five species--pig, horse, sheep, cat and rat--were evaluated. Samples were illuminated individually by a helium-neon laser light from the buccal surface using a probe 0.5 mm in diameter placed at varying angles between 60 and 120 degrees C. The pattern of light transmission was observed macroscopically. Further evaluation of laser light transmission in enamel was achieved using confocal microscopy.
  
  
  RESULTS
  In each species, light was transmitted through the tooth to the pulp, but in the cat and the rat, light was also transmitted to the far side of the tooth. Despite the different patterns of enamel in the species, light was transmitted through enamel to dentine.
  
  
  CONCLUSIONS
  Light from a laser Doppler probe appeared to reach the dental pulp in all the species: however, in the mammals with smaller teeth, light may also have been able to reach the periodontium and thus the reflected signal may not be entirely of pulpal origin.
authors.affiliation: Department of Conservative Dentistry, GKT School of Dentistry, King's College, London, UK.
authors.forename: T M
authors.initials: TM
authors.lastname: Odor
authors.forename: N P
authors.initials: NP
authors.lastname: Chandler
authors.forename: T F
authors.initials: TF
authors.lastname: Watson
authors.forename: T R
authors.initials: TR
authors.lastname: Ford
authors.forename: F
authors.initials: F
authors.lastname: McDonald
mesh_terms: D000818:Animals; D002415:Cats; D003743:Dental Enamel / Q000033:anatomy & histology*; D003804:Dentin / Q000033:anatomy & histology; D006736:Horses; D017078:Laser-Doppler Flowmetry; D007834:Lasers; D018613:Microscopy, Confocal; D051381:Rats; D012756:Sheep; D013045:Species Specificity; D013552:Swine; D014172:Transillumination