1. Department of Mechanical and Materials Engineering, Tatung University, Taipei 104-327, Taiwan
2. Research Center of Digital Oral Science and Technology, College of Oral Medicine, Taipei Medical University, Taipei 110-301, Taiwan
3. Graduate Institute of Manufacturing Technology, National Taipei University of Technology, Taipei 106-344, Taiwan
4. School of Dental Technology, College of Oral Medicine, Taipei Medical University, Taipei 110-301, Taiwan