1. Department of Periodontology, Daejeon Dental Hospital, Wonkwang University College of Dentistry, Daejeon 35233, Republic of Korea
2. Department of Health Insurance Research, Ilsan Hospital, National Health Insurance Service, Goyang 10444, Republic of Korea
3. Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul 03722, Republic of Korea