1. Department of Oral and Maxillofacial Surgery, School of Dentistry, Kyung Hee University, Seoul 02447, Republic of Korea
2. Department of Dental Hygiene, Division of Health Science, Baekseok University, Cheonan 31065, Republic of Korea
3. School of Mechanical Engineering, Korea University, Seoul 02841, Republic of Korea
4. Department of Dental Hygiene, Konyang University, Daejeon 35365, Republic of Korea