Determination of Spectroscopic Changes in Caries Teeth Using Laser Induce Breakdown Spectroscopy (LIBS)

Abstract

Dedication To the spirit of my father . To my family ( mother, sisters and my brother). To all my great teachers. To all colleagues , friends and anyone who helped me to finish this research . . ii Acknowledgement I would like to thank God firstly for helping me and giving me life, he a lth and time to accomplish this work .Thanks to Sudan University of Science and Technology - Institute of Laser for giving me the opportunity to present this work. I extend my gr atitude to my supervisor Prof. Nafie A. Al muslet who gave me much useful advice and support which has encouraged me throughout this whole process . I would like to thank Dr. Maria for her helping me in the experimental part of this work . Many thanks to Mr Ali Moh a med Ahmed Taha the General m a nage r of Anglo Tr a ding that support me financially and morally. I would like to extend my gratefulness and thanks to all my colleagues in the Institute of Laser a nd in Sudan academy For science and to everyone who have helped me with his valuable advices and efforts . To All the people in my life , thanks a lot for help and encouragement. iii Abstract The objective of this research was the utilization of laser induced breakdown spectroscopy (LIBS) technique to determine the spectroscopic changes in caries teet h. Q - Switched Nd:YAG laser with 10 ns pulse duration, 100 mj energy per pulse, 2 Hz repetition rate was used. Five caries teeth were used as samples. Each tooth has been divided into three region s for irradiation; the first region is the health, the second is the region of caries and the third region is the edge between the health region and the caries region. Each region was irradiated with the same parameters. The laser beam was focused on the sample to achieve high power density leads to very high tempe rature in the focal volume and then undergo a number of reactions result ing in formation of plasma of the sample. This plasma emits discrete emission lines which represent the fingerprint of the sample. A spectrometer connected to PC was used to collect a nd record the emission spectra of the samples plasma. The recorded spectra were processed by subtracting : the dark current, the pumping flashlamp and the background radiation . The elements in the emission spectra were id entified after referring to the ato mic spectra database. A comparison was done betw een the sample contents i n order to determine the spectral differences between the health part and caries part of each tooth . The results showed that certain elements were found in all the five samples with different amounts while some elements were no t found in all the five teethه