1. Department of Orthodontics, Nihon University Graduate School of Dentistry at Matsudo, Chiba, Japan
2. Department of Orthodontics, Nihon University School of Dentistry at Matsudo, Chiba, Japan
3. Graduate School of Information Science, Hiroshima City University, Hiroshima, Japan
4. Department of Mathematical Science, Nihon University School of Dentistry at Matsudo, Chiba, Japan