1. Department of Prosthodontics, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea.
2. Department of Polymer Science & Engineering, School of Applied Chemical Engineering, Kyungpook National University, Daegu, Republic of Korea.
3. Department of Dental Biomaterials, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea.