الفهرس 
INTRODUCTION AND LITERATURE REVIEWOnly 14 pages are availabe for public view
 |  | from | 111 |  |  |
| | | from | 111 | | |
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.
Abstract
xi
The linear relation between the shift and load was directly
proportional. The empirical formula between the shifts of the tooth due
to an external load applied to it (simulating shewing process) has been
obtained.
Achieved results revealed that there is no significant statistically
difference between the mean value of surface shift measured by laser
speckle photography and that calculated by finite element analysis as the
correlation coefficient (r) between them was = 1. Also there is no
statistically significant difference between measurements obtained with
He-Ne LASER and LASER diode.