Evaluation of periodontitis-related tooth loss according to the new 2018 classification of periodontitis oleh Masahide Takedachi, Yoshio Shimabukuro, Keigo Sawada, Mami Koshimizu, Kazuko Shinada, Harumi Asai, Ayumi Mizoguchi, Yuko Hayashi, Akina Tsukamoto, Midori Miyago, Fuuka Nishihara, Takako Nishihata, Michiyo Shimabukuro, Hiroyuki Kurakami, Tomoharu Sato, Yayoi Hamazaki, Tomoaki Iwayama, Chiharu Fujihara, Shinya Murakami