title: Two cases with supernumerary teeth in lower incisor region.
abstract: Abnormalities in number of teeth are occasionally noted in clinical cases. Many theories have been proposed as regards the causes of the occurrence of supernumerary teeth, including atavism theory, mechanical tooth germ separation theory, tissue induction theory, and dental laminar morphological disturbance theory. However, none of these theories alone offers a sufficient explanation for this phenomenon. The incidence of supernumerary permanent teeth is approximately 1-3%. These are the maxillary anterior teeth, the maxillary molars, and the maxillo-mandibular premolars in terms of descending order of site of occurrence. On the other hand, incidence in the mandibular anterior tooth area, of which there have been few detailed reports, is about 0.01%, a markedly low value. In this paper, we report two rare cases of supernumerary teeth in the mandibular incisor area. We discuss their etiology and orthodontic treatment, and detail a differential diagnosis between the normal and supernumerary teeth. We found that it was difficult to establish a clear etiology and differentiation between the normal and supernumerary teeth.
authors.affiliation: Department of Orthodontics, Tokyo Dental College, Chiba, Japan. yokose@tdc.ac.jp
authors.forename: Taishi
authors.initials: T
authors.lastname: Yokose
authors.forename: Teruo
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Kenji
authors.initials: K
authors.lastname: Sueishi
authors.forename: Kenichi
authors.initials: K
authors.lastname: Yatabe
authors.forename: Keiichirou
authors.initials: K
authors.lastname: Tsujino
authors.forename: Shuhei
authors.initials: S
authors.lastname: Kubo
authors.forename: Masashi
authors.initials: M
authors.lastname: Yakushiji
authors.forename: Hideharu
authors.initials: H
authors.lastname: Yamaguchi
mesh_terms: D000293:Adolescent; D003937:Diagnosis, Differential; D005260:Female; D005671:Fused Teeth / Q000150:complications / Q000601:surgery; D006801:Humans; D007180:Incisor / Q000002:abnormalities*; D008297:Male; D008310:Malocclusion / Q000150:complications / Q000628:therapy; D008334:Mandible; D009971:Orthodontics, Corrective; D011862:Radiography, Panoramic; D014081:Tooth Extraction; D014096:Tooth, Supernumerary / Q000150:complications / Q000601:surgery