1. School of Materials Science & Engineering, Chonnam National University, Gwangju 61186, Republic of Korea
2. Powder Materials Division, Korea Institute of Materials Science, 51508 Changwon, South Korea
3. Department of Prosthodontics, School of Dentistry, Chonnam National University, Gwangju 61186, Republic of Korea
4. Gachon Pain Center and Department of Physiology, College of Medicine, Gachon University, Incheon 21999, Republic of Korea