title: Prevalence of teeth number anomalies in orthodontic patients.
abstract: OBJECTIVE
  The purpose of this study was to determine if the prevalence of teeth number anomalies (TNA) is more frequent in orthodontic patients than in common population and what is TNA clinical manifestation.
  
  
  METHODS
  The records of 824 orthodontic patients (average age 15.22 years) from Orthodontic Clinic of Lithuanian University of Health Sciences were analyzed. The radiographs were analyzed by trained observer who followed a pre-established protocol: general observation of the teeth including third molar, followed by a systematic analysis of the erupted and unerupted teeth number in each quadrant. Descriptive statistics were performed for the study variables. A chi-square test was used to determine the difference in the prevalence of hypodontia between the genders. A value of P<0.05 was considered significant.
  
  
  RESULTS
  The prevalence of hypodontia was 17.11 percent with no statistically significant difference between the genders (P>0.05). More frequently teeth were missing in the lower jaw: in the upper jaw - 10.3%, in the lower - 12.5% without statisticaly significant diference. Unilateral occurrence of dental agenesis was 1.5 times more common than bilateral occurrence. If more than one tooth was missing, usually other missing tooth was in the same group and in the same jaw. The upper and lower third molars were the most frequently missing teeth, followed by the mandibular second premolar. The prevalence of hyperdontia was 0.85 percent. Mesiodens was the most frequently found supernumerary tooth.
  
  
  CONCLUSIONS
  It was found, that 17.96% of orthodontic patients had teeth number anomalies. The upper and lower third molars were the most frequently missing teeth, followed by the mandibular second premolar. Hypodontia occurred more frequently than hyperdontia. Mesiodens was the most frequently found supernumerary tooth. The results confirm that TNA are more often found in orthodontic patients and these patients should be treated with multidisciplinary approach.
authors.affiliation: Clinic of Orthodontics, Lithuanian University of Health Sciences, Lukšos-Daumanto 6, LT-50106, Kaunas, Lithuania. gyd_trakiniene@yahoo.com.
authors.forename: Giedrė
authors.initials: G
authors.lastname: Trakinienė
authors.forename: Monika
authors.initials: M
authors.lastname: Ryliškytė
authors.forename: Aurelija
authors.initials: A
authors.lastname: Kiaušaitė
mesh_terms: D000293:Adolescent; D000848:Anodontia / Q000150:complications / Q000453:epidemiology*; D002648:Child; D005260:Female; D006801:Humans; D008097:Lithuania / Q000453:epidemiology; D008297:Male; D008310:Malocclusion / Q000150:complications; D009971:Orthodontics, Corrective; D015995:Prevalence; D012189:Retrospective Studies; D012737:Sex Factors; D014096:Tooth, Supernumerary / Q000150:complications / Q000453:epidemiology; D055815:Young Adult