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For this research the spectral optical characteristics (diffuse spectral reflectance and transmittance) for a number of human teeth were measured in the 250 to 1500 nm region of the electromagnetic spectrum. From the reflectance and transmittance of the dental enamel the spectral absorptance and thus the attenuation coefficient can be determined. The optical characteristics of the human incisor/molar samples were measured with a Hitachi U3400 spectrophotometer and 60 mm (Phi) integrating sphere (IS) attachment, using a photomultiplier tube and PbS detectors. The characteristics of the IS attachment restricted the effective range of wavelengths that could be used to 250 - 1500 nm, which is also the wavelength range of interest. It is clear from the reflectance and transmittance characteristics of dental enamel that absorption is significantly higher in the UV and NIR regions than in the visible, with the attenuation coefficient the highest in the UV region from 250 to approximately 400 nm. The UV wavelengths may therefore prove to be extremely beneficial for laser dental procedures as a result of (1) better absorption, (2) simpler delivery systems than for CO2, (3) possible germicidal effects at approximately equals 250 nm, (4) higher optical resolution attainable, and (5) reduced stray reflections from the tooth surfaces.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. |
