title: Laser ultrasonic surface wave dispersion technique for non-destructive evaluation of human dental enamel.
abstract: This paper describes a novel optical system for clinical diagnosis of dental enamel based on its elasticity. Current examination techniques are typically destructive, and frequently impractical for in-vivo inspection. This paper describes the first application of a laser ultrasonic non-destructive evaluation (NDE) method for clinical dental diagnosis. It performs remote elasticity evaluation on small dimension samples. A focused laser line-source generates broadband surface acoustic wave (SAW) impulses which are detected with a simplified optical fibre interferometer. The measured SAW velocity dispersion spectrum was in turn used to characterise the elasticity of the specimen. Different metal structures were measured to verify the system performance. The results agree well with theoretical values and confirm the reliability and accuracy of the laser NDE system. This technique was then applied to evaluate the surface of sound natural human dental enamel. The measured dispersion spectra match theoretical expectations and the influences of both the enamel and the underlying dentin on the surface wave propagation were observed. This is the first time, to the best of our knowledge, that a laser based SAW velocity dispersion technique has been successfully applied on human dental enamel. As a remote, non-destructive technique it is applicable in-vivo and opens the way for early diagnosis of dental caries.
authors.affiliation: Institue of Photonics and Optical Science, School of Physics, University of Sydney, NSW 2006, Australia. david.wang@usyd.edu.au
authors.forename: Hsiao-Chuan
authors.initials: HC
authors.lastname: Wang
authors.forename: Simon
authors.initials: S
authors.lastname: Fleming
authors.forename: Yung-Chun
authors.initials: YC
authors.lastname: Lee
authors.forename: Sue
authors.initials: S
authors.lastname: Law
authors.forename: Michael
authors.initials: M
authors.lastname: Swain
authors.forename: Jing
authors.initials: J
authors.lastname: Xue
mesh_terms: D003198:Computer Simulation; D003743:Dental Enamel / Q000000981:diagnostic imaging* / Q000502:physiology*; D055119:Elastic Modulus / Q000502:physiology; D054459:Elasticity Imaging Techniques / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008954:Models, Biological