Ti:sapphire femtosecond laser interaction with human dental dentine

This paper reports an investigation of the characteristics of human dentine ablated by a femtosecond laser of 800 nm wavelength for potential pain free dental restoration applications. The work has shown that precise femtosecond laser ablation with clear boundaries and without cracks and debris can be obtained. The transmittance of the dentine tissue was ∼2·7%, and the absorption coefficient was ∼3·19 cm-1 at 800 nm. The laser processed dentine morphology was investigated over a wide range of laser fluences and pulse numbers. The fluence threshold of dentine was determined as 0·45 J cm-2 according to the experimental dependence of the ablated depth versus laser fluence. The thermal energy conduction effects of dentine tubules were analysed. The SEM-EDX and Raman mapping analysis of phosphate indicate that the chemical components of the dentine remained intact before and after ablation. © 2011 Institute of Materials, Minerals and Mining.