title: Is there an association between skeletal asymmetry and tooth absence?
abstract: BACKGROUND
  Facial skeletal asymmetry is commonly found in humans and its main characteristic is menton deviation. The literature suggests that occlusal and masticatory problems arising from tooth absence could be related to the development of such asymmetries.
  
  
  OBJECTIVE
  The aim of this cross-sectional study was to estimate the prevalence of mandibular skeletal asymmetries and to investigate its association with posterior tooth absences.
  
  
  METHODS
  Tomographic images of 952 individuals aged from 18 to 75 years old were used. Asymmetry was the analyzed outcome, and it was categorized into three groups according to gnathion displacement in relation to the midsagittal plane (relative symmetry, moderate asymmetry, and severe asymmetry). Patients were sorted by the presence of all posterior teeth, unilateral posterior tooth absence, or bilateral posterior tooth absence. Chi-square test with a significance level of 5% was used to verify the association between posterior tooth absence and asymmetry.
  
  
  RESULTS
  Results show relative symmetry present in 55.3% of the sample, as well as the prevalence of 27.3% for moderate mandibular asymmetry and 17.4% for severe asymmetry. Moderate and severe mandibular asymmetries occurred in a higher proportion in patients with unilateral posterior tooth absence. However, there was no statistically significant difference between the analyzed groups (p = 0.691).
  
  
  CONCLUSIONS
  In this study, mandibular asymmetries did not present any association with the absence of teeth on the posterior area of the arch.
authors.affiliation: Professor of Orthodontics, Universidade do Sul de Santa Catarina (UNISUL), Florianópolis, Santa Catarina, Brazil.
authors.forename: Guilherme
authors.initials: G
authors.lastname: Thiesen
authors.affiliation: MSc, Pontifícia Universidade Católica de Minas Gerais (PUC-MG), Belo Horizonte, MG, Brazil.
authors.forename: Bruno Frazão
authors.initials: BF
authors.lastname: Gribel
authors.affiliation: Professor of Epidemiology, Universidade do Sul de Santa Catarina (UNISUL), Florianópolis, SC, Brazil.
authors.forename: Keila Cristina Rausch
authors.initials: KC
authors.lastname: Pereira
authors.affiliation: Professor of Orthodontics, Universidade Luterana do Brasil (ULBRA), Canoas, RS, Brazil.
authors.forename: Maria Perpetua Mota
authors.initials: MP
authors.lastname: Freitas
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005146:Facial Asymmetry / Q000150:complications* / Q000000981:diagnostic imaging / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008409:Mastication; D008875:Middle Aged; D015995:Prevalence; D019252:Radiography, Dental, Digital; D016388:Tooth Loss / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D055815:Young Adult