Detection of dental rough surface shift using laser speckle photography technique

Abstract

The use of coherent light for imaging through highly scattering media, including biological tissues, is an active area for medical research. Scattered coherent wavelets from human tissue lead to deformation of the bio speckle fingerprint of tissue. Laser speckle phenomenon has been extensively explored; in particular, speckle analysis has been used in several optical surface roughness techniques. The technique of laser speckle formed by scattered coherent wavelets of teeth rough surface is presented to correlate between teeth surface roughness and laser bio speckle pattern contrast. This thesis presents a novel method to measure the shift in tooth rough surface as a result of applying different loads by using laser speckle photography technique. Two lasers were used (He-Ne LASER with power = 5 mW and wavelength = 632.8 nm and LASER diode with power = 3 mW and wavelength = 375 nm). Two groups of teeth were used, each of them consists of eight premolar teeth mounted in acrylic cylindrical blocks parallel to their long axis. They were held by a custom jig at 45° angle in a specially constructed device to apply different loads (100 g to 3 kg). Amount of teeth rough surface shift was measured. The tooth rough surface shift varied between 1.000001 and 70.00006 pixel.