[1] Seoul Natl Univ, Dept Comprehens Treatment Ctr, Dent Hosp, Seoul 03080, South Korea
[2] Seoul Natl Univ, Sch Dent, Dent Res Inst, Dept Oral Microbiol & Immunol, Seoul 08826, South Korea
[3] Seoul Natl Univ, Plus Program BK21, Seoul 08826, South Korea
[4] Univ Western Ontario, Schulich Sch Med & Dent, London, ON N6A 5C1, Canada
[5] Seoul Natl Univ, Sch Dent, Dent Res Inst, Dept Conservat Dent,Dent Hosp, Seoul 03080, South Korea
[6] Seoul Natl Univ, Dent Hosp, Sch Dent, Plus Program BK21, Seoul 03080, South Korea
[7] Seoul Natl Univ, Natl Dent Care Ctr Persons Special Needs, Dent Hosp Persons Special Needs, Seoul 03080, South Korea