title: LED light attenuation through human dentin: a first step toward pulp photobiomodulation after cavity preparation.
abstract: OBJECTIVE
  To evaluate the transdentinal light attenuation of LED at three wavelengths through different dentin thicknesses, simulating cavity preparations of different depths.
  
  
  METHODS
  Forty-two dentin discs of three thicknesses (0.2, 0.5 and 1 mm; n = 14) were prepared from the coronal dentin of extracted sound human molars. The discs were illuminated with a LED light at three wavelengths (450+/-10 nm, 630 +/-10 nm and 850 +/-10 nm) to determine light attenuation. Light transmittance was also measured by spectrophotometry.
  
  
  RESULTS
  In terms of minimum (0.2 mm) and maximum (1.0 mm) dentin thicknesses, the percentage of light attenuation varied from 49.3% to 69.9% for blue light, 42.9% to 58.5% for red light and 39.3% to 46.8% for infrared. For transmittance values, an increase was observed for all thicknesses according to greater wavelengths, and the largest variation occurred for the 0.2 mm thickness. All three wavelengths were able to pass through the dentin barrier at different thicknesses. Furthermore, the LED power loss and transmittance showed wide variations, depending on dentin thickness and wavelength.
authors.forename: Ana Paula S
authors.initials: AP
authors.lastname: Turrioni
authors.forename: Juliana R L
authors.initials: JR
authors.lastname: Alonso
authors.forename: Fernanda G
authors.initials: FG
authors.lastname: Basso
authors.forename: Lilian T
authors.initials: LT
authors.lastname: Moriyama
authors.forename: Josimeri
authors.initials: J
authors.lastname: Hebling
authors.forename: Vanderlei S
authors.initials: VS
authors.lastname: Bagnato
authors.forename: Costa Carlos A
authors.initials: CC
authors.lastname: De Souza
mesh_terms: D003737:Dental Cavity Preparation; D003782:Dental Pulp / Q000473:pathology / Q000528:radiation effects*; D003804:Dentin / Q000473:pathology / Q000528:radiation effects*; D006801:Humans; D007259:Infrared Rays; D008027:Light; D010789:Phototherapy / Q000379:methods; D011829:Radiation Dosage; D013053:Spectrophotometry; D013997:Time Factors