J. Phys. IV France 125 (2005) 721-723
DOI: 10.1051/jp4:2005125165

Photothermal radiometric quantitative detection of the different degrees of demineralization of dental enamel by acid etching

R.J. Jeon¹, T.D.T. Phan², A. Wu¹, G. Kulkarni², S.H. Abrams³ and A. Mandelis<sup>1

1</sup>  Center for Advanced Diffusion Wave Technologies, Dept. of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario, Canada M5S 3G8, Canada
²  Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
³  Four Cell Consulting, 748 Briar Hill Ave., Toronto, Ontario, Canada M6B 1L3, Canada

Abstract
Photothermal radiometric (FD-PTR or PTR) signals from human teeth have been used toward detecting an artificial surface demineralization. The aim of the study is to characterize PTR signals by using controlled mineral loss from human enamel to mimic surface and subsurface dental caries. At a fixed modulation frequency, an Ar⁺ ion laser was used as a light source to scan across the tooth surface, and an MCT infrared detector was used for measuring the PTR signals. Several human molar teeth were etched using 37% phosphoric acid etching gel and scanned across the etched region at 30 Hz. PTR amplitude from the etched region shows that the signal decreases with increasing etching time. The PTR phase also shows the same behavior with the amplitude and better contrast between different etching times. The PTR technique could thus be used to detect early surface demineralization and may give the examiner quantitative information of the degree of demineralization in dental caries.

© EDP Sciences 2005