title: Prevalence and distribution of anomalies of permanent dentition in 9584 Japanese high school students.
abstract: This study investigated the prevalence and distribution of anomalies of permanent dentition in the current Japanese population by examining an unbiased sample. We conducted a survey of dental anomalies by mass dental screening at eight high schools in 2012. Participants were all students with permanent dentition. Dental anomalies were classified as hypodontia, supernumerary teeth, peg-shaped teeth, fused teeth, and talon cusps. Students with one or more dental anomalies on oral examination were given a differential diagnosis by three specialists. The final sample comprised 9584 participants (5062 boys, 4522 girls). Hypodontia was present in 372 students (3.88 %) with no significant sex difference (191 boys, 181 girls). Frequent sites were the right or left mandibular second premolar, right or left maxillary second premolar, and right or left maxillary lateral incisor. Supernumerary teeth were observed in three boys (0.06 %) and one girl (0.02 %). Peg-shaped teeth were observed in 74 students (0.77 %; 27 boys, 47 girls), differing significantly between sexes; they were most prevalent among maxillary lateral incisors. Of affected students, 18 students (0.19 %) also had hypodontia (3 boys, 15 girls). Fused teeth were present in two boys (0.04 %) and three girls (0.07 %) (gemination in one boy and fusion in the remaining four students). Sites were limited to maxillary and mandibular central and lateral incisors. Talon cusps were observed in two boys (0.04 %) and four girls (0.09 %). The present survey of a large unbiased sample can be considered to reflect the prevalence and distribution of anomalies of permanent dentition in the current Japanese population.
authors.affiliation: Department of Fixed Prosthodontics, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo, 101-8310, Japan. hagiwara.yoshiyuki@nihon-u.ac.jp.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Hagiwara
authors.affiliation: Department of Community Dentistry, Nihon University School of Dentistry, Tokyo, Japan.
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Uehara
authors.affiliation: Department of Complete Denture Prosthodontics, Nihon University School of Dentistry, Tokyo, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Narita
authors.affiliation: Department of Legal Medicine, Nihon University School of Dentistry, Tokyo, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Tsutsumi
authors.affiliation: Department of Partial Denture Prosthodontics, Nihon University School of Dentistry, Tokyo, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Nakabayashi
authors.affiliation: Department of Oral and Maxillofacial Radiology, Nihon University School of Dentistry, Tokyo, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Araki
mesh_terms: D000293:Adolescent; D019229:Dentition, Permanent; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008403:Mass Screening; D015995:Prevalence; D014071:Tooth Abnormalities / Q000453:epidemiology*
keywords: Dental anomalies; Hypodontia; Permanent dentition; Prevalence