[1] Cheongju Univ, Coll Hlth Sci, Dept Dent Hyg, Cheongju, South Korea
[2] Iwate Med Univ, Sch Dent, Dept Prevent Dent, Morioka, Iwate, Japan
[3] Yonsei Univ, Coll Dent, Oral Sci Res Inst, Dept Prevent Dent & Publ Oral Hlth,PLUS Project B, Seoul, South Korea
[4] Yonsei Univ, Coll Dent, Dept Orofacial Pain & Oral Med, Seoul 120749, South Korea