title: Association analysis of clinical aspects and vitamin D receptor gene polymorphism with external apical root resorption in orthodontic patients.
abstract: BACKGROUND
  Vitamin D is responsible for the regulation of certain genes at the transcription level, via interaction with the vitamin D receptor, and influences host immune responses and aspects of bone development, growth, and homeostasis. Our aim was to investigate the association of TaqI vitamin D receptor gene polymorphism with external apical root resorption during orthodontic treatment.
  
  
  METHODS
  Our subjects were 377 patients with Class II Division 1 malocclusion, divided into 3 groups: (1) 160 with external apical root resorption ≤1.43 mm, (2) 179 with external apical root resorption >1.43 mm), and (3) 38 untreated subjects. External apical root resorption of the maxillary incisors was evaluated on periapical radiographs taken before and after 6 months of treatment. After DNA collection and purification, vitamin D receptor TaqI polymorphism analysis was performed by polymerase chain reaction-restriction fragment length polymorphism. Univariate and multivariate analyses were performed to verify the association of clinical and genetic variables with external apical root resorption (P <0.05).
  
  
  RESULTS
  There was a higher proportion of external apical root resorption in orthodontically treated patients compared with the untreated subjects. In patients orthodontically treated, age higher than 14 years old, initial size of the maxillary incisor root superior to 30 mm, and premolar extraction were associated with increased external apical root resorption. Genotypes containing the C allele were weakly associated with protection against external apical root resorption (CC + CT × TT [odds ratio, 0.29; 95% confidence interval, 0.07-1.23; P = 0.091]) when treated orthodontic patients were compared to untreated individuals.
  
  
  CONCLUSIONS
  Clinical factors and vitamin D receptor TaqI polymorphism were associated with external apical root resorption in orthodontic patients.
authors.affiliation: School of Health and Biosciences, Pontifícia Universidade Católica do Paraná, Curitiba-PR, Brazil.
authors.forename: Maria Luiza S Simas Netta
authors.initials: ML
authors.lastname: Fontana
authors.forename: Cleber Machado
authors.initials: CM
authors.lastname: de Souza
authors.forename: José Fabio
authors.initials: JF
authors.lastname: Bernardino
authors.forename: Felix
authors.initials: F
authors.lastname: Hoette
authors.forename: Maura Levi
authors.initials: ML
authors.lastname: Hoette
authors.forename: Lotario
authors.initials: L
authors.lastname: Thum
authors.forename: Terumi O
authors.initials: TO
authors.lastname: Ozawa
authors.forename: Leopoldino
authors.initials: L
authors.lastname: Capelozza Filho
authors.forename: Marcia
authors.initials: M
authors.lastname: Olandoski
authors.forename: Paula Cristina
authors.initials: PC
authors.lastname: Trevilatto
mesh_terms: D000293:Adolescent; D016009:Chi-Square Distribution; D002648:Child; D003562:Cytidine / Q000235:genetics; D003799:Dental Stress Analysis; D005260:Female; D006801:Humans; D007180:Incisor / Q000033:anatomy & histology; D016015:Logistic Models; D008297:Male; D008312:Malocclusion, Angle Class II / Q000628:therapy; D009811:Odontometry; D009967:Orthodontic Appliances / Q000009:adverse effects*; D012150:Polymorphism, Restriction Fragment Length; D020641:Polymorphism, Single Nucleotide; D018167:Receptors, Calcitriol / Q000235:genetics*; D012391:Root Resorption / Q000209:etiology / Q000235:genetics*; D014092:Tooth Root / Q000033:anatomy & histology; D055815:Young Adult
chemical_list: D018167:Receptors, Calcitriol; D003562:Cytidine