1. Pusan National University, School of Dentistry, Department of Conservative Dentistry, Yangsan 50612, Republic of Korea
2. Kookmin University, Department of Electrical Engineering, Seoul 02707, Republic of Korea
3. University of North Carolina, School of Dentistry, Department of Orthodontics, Chapel Hill, North Carolina 27599, United States
4. Pusan National University, School of Dentistry, Department of Dental Materials, Yangsan 50612, Republic of Korea