Imaging of Dental Hard Tissue Surfaces Prepared by an Ultrashort Pulsed Laser System (USPL)

Abstract

AbstractThe aim of this study was to compare surface structures of laser-irradiated dental hard tissues using confocal (CFM), atomic force (AFM), and scanning electron microscopy (SEM). The general potential of the AFM in analyzing laser-irradiated surfaces was determined in this context. Specimens of human enamel and dentin were irradiated using an 8.6 W Nd:YVO4laser with a pulse duration of 8 ps,λCenter=1,064 nm, and a pulse repetition rate of 500 kHz. Surface topology of irradiated areas (1 mm2) was investigated using AFM, CFM, and SEM. Surface roughnessRzwas measured only with the AFM and the CFM. For non-irradiated enamel and dentin surfaces, roughnesses for CFM and AFM are in the nanometer range. However, major differences in roughness were determined for laser-prepared surfaces. For enamel,Rz(CFM)=2.33μm is much higher compared withRz(AFM)=0.09μm; in the case of dentin,Rz(CFM)=5.35μm is also much higher compared withRz(AFM)=0.093μm. Information regarding structural properties of surfaces needs real dimensions, particularly for use in dentistry. In this respect, AFM technology provides no additional results that lead to a significant improvement.