Gwangju,KoreaDecember,2010ApprovedbyProfessorKimByung-OckMajorAdvisor BySeokSangDongAdvisor:Prof.KimByung-Ock,D.D.s.,M.S.D.,Ph.D.DepartmentofDentistryGraduateschoolofChosunUniversityAthesissubmittedoftheChosunUniversityinpartialfulfillmentoftherequirement