title: Patterns of non-syndromic permanent tooth agenesis in a large orthodontic population.
abstract: OBJECTIVE
  The aim of this study is to explore patterns of non-syndromic permanent tooth agenesis in a large orthodontic patient group.
  
  
  METHODS
  A record review was performed in various orthodontic clinics to identify white patients with non-syndromic permanent tooth agenesis, excluding 3rd molars. Four hundred and fourteen subjects fulfilled the inclusion criteria.
  
  
  RESULTS
  In the 414 subjects with tooth agenesis, approximately 70% presented 1-2 missing teeth. Symmetric agenesis patterns were often observed in the sample (by jaw, by side, or crossed quadrants), with prevalence approaching 30% for cases with contralateral tooth agenesis within a jaw. In cases with 1 or 2 missing teeth, from the total number of potential tooth agenesis patterns in the sample, a certain part was evident, limiting the variation to 27.8% (44/158). In the entire sample, both in the maxilla and the mandible a certain incisor/premolar agenesis phenotype was observed in 59.0% of cases in isolated form.
  
  
  CONCLUSIONS
  Although there was variation in the tooth agenesis patterns, our findings suggest the involvement of particular genetic, epigenetic, and/or environmental factors in the formation of the entire dentition, which often lead to specific tooth agenesis phenotypes in cases where this process is disrupted. The present study provides a comprehensive categorization of orthodontic cases with tooth agenesis and can assist in planning future epidemiological and genetic studies.
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Freiburgstrasse 7, CH-3010, Bern, Switzerland. Electronic address: nikolaos.gkantidis@zmk.unibe.ch.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Gkantidis
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Freiburgstrasse 7, CH-3010, Bern, Switzerland.
authors.forename: Hattan
authors.initials: H
authors.lastname: Katib
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Freiburgstrasse 7, CH-3010, Bern, Switzerland.
authors.forename: Elias
authors.initials: E
authors.lastname: Oeschger
authors.affiliation: Department of Orthodontics, School of Dentistry, University of Athens, 2 Thivon Str, 115 27, Goudi, Athens, Greece.
authors.forename: Marina
authors.initials: M
authors.lastname: Karamolegkou
authors.affiliation: Department of Orthodontics, Aristotle University of Thessaloniki, University Campus, 54 124, Thessaloniki, Greece.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Topouzelis
authors.affiliation: Department of Orthodontics, Tufts University School of Dental Medicine, 1 Kneeland Street, MA 02111, Boston, USA.
authors.forename: Georgios
authors.initials: G
authors.lastname: Kanavakis
mesh_terms: D000293:Adolescent; D000328:Adult; D000848:Anodontia / Q000000981:diagnostic imaging / Q000453:epidemiology*; D001641:Bicuspid / Q000002:abnormalities; D002648:Child; D005260:Female; D006801:Humans; D007180:Incisor / Q000002:abnormalities; D008297:Male; D008334:Mandible; D008437:Maxilla; D008964:Molar, Third / Q000002:abnormalities; D009970:Orthodontics; D015995:Prevalence; D011862:Radiography, Panoramic; D013557:Switzerland / Q000453:epidemiology; D016388:Tooth Loss; D055815:Young Adult
keywords: Non-syndromic; Orthodontic patients; Permanent dentition; Tooth agenesis