1. Department of Dentistry and Oral Surgery, Hakujikai Memorial General Hospital, 5-11-1 Shikahama, Adachi-ku, Tokyo 123-0864, Japan
2. Department of Oral and Maxillofacial Surgery, School of Dental Medicine, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, Kanagawa 230-8501, Japan
3. Division of Community Based Comprehensive Dentistry, Department of Special Needs Dentistry, School of Dentistry, Showa University, 2-1-1 Kitasenzoku, Ota-ku, Tokyo 145-8515, Japan
4. Department of Dentistry and Oral Surgery, Jinkokai Hospital, 3-8-11 Nakamachi, Atsugi, Kanagawa 243-0018, Japan