Three-dimensional microstructure characteristics and evolution on dentin surface induced by ultraviolet laser irradiation

In texturing dentin surface by KrF laser with the fluences of 200–800 mJ/cm2, it is observed the irradiated surface topography has different characteristics with that irradiated under high fluence above 1000 mJ/cm2 reported in previous studies. The formation threshold fluence of the microstructure consisted of erected microcylinders was determined at 400 mJ/cm2. By scanning electron microscopy including fine examination of a single microstructure unit under high magnification, the microstructure formation and evolution tending to the fashion of high fluence were given. Analysis of the ablation details captured by high-speed photography confirmed the development mechanism of the texturing microstructure. Raman analysis showed the composition of the laser textured dentin underwent changes. Although the texturing is related to the characteristics of the dentin tissue, laser parameters play a decisive role in the controlling of the shape and the height of the three-dimensional microstructure. The combination of our work and the previous work by Sivakumar et al. [J. Laser Appl. 18(4), 330–333 (2006) and Lasers Med. Sci. 21, 160–164 (2006)] demonstrates laser fabrication of the three-dimensional microstructure with different topography features on dentin surface is controllable.