title: Nickel-free vs conventional braces for patients allergic to nickel: Gingival and blood parameters during and after treatment.
abstract: BACKGROUND
  Allergic and inflammatory reactions have commonly been associated with the release of metal ions during orthodontic treatment. Our objective was to evaluate prospectively gingival and blood status in patients allergic to nickel.
  
  
  METHODS
  Allergy to nickel was diagnosed using a patch test. Two groups were established: conventional braces (n = 21) and nickel-free braces (n = 21). The gingival index was used to determine gingival status before treatment, periodically for 12 months (evaluations every 3 months), and 1 month after the removal of the braces. Blood status was evaluated with a complete blood count, including the quantification of nickel and immunoglobin E before treatment, during treatment, and 1 month after removal of the braces. The data were analyzed using Mann-Whitney, Student t, Wilcoxon, repeated measures analysis of variance, Friedman, and chi-square tests. Either the Pearson or the Spearman correlation coefficients were calculated, when appropriate.
  
  
  RESULTS
  The number of basophils increased significantly among the evaluations in both groups (conventional, P = 0.002; nickel-free, P = 0.001), whereas the number of eosinophils and the immunoglobin E levels decreased significantly in the conventional group (P = 0.004). Plasma nickel levels were increased before and during treatment, and decreased 1 month after removing the braces in both groups, but the differences were significant only in the nickel-free group (P = 0.002). No correlations were found between the concentrations of nickel and immunoglobin E, basophils, or eosinophils, or between the gingival index and either bands or segmented neutrophils (P ≥ 0.05).
  
  
  CONCLUSIONS
  Patients treated with nickel-free braces had better gingival health and smaller blood changes than did those treated with conventional braces. All abnormalities tended to be eliminated after the removal of the braces.
authors.affiliation: Postgraduate student, Department of Pediatric Dentistry and Orthodontics, Faculty of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil. Electronic address: camilapazzini@hotmail.com.
authors.forename: Camila Alessandra
authors.initials: CA
authors.lastname: Pazzini
authors.affiliation: Professor, Department of Health Sciences, Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil.
authors.forename: Luciano José
authors.initials: LJ
authors.lastname: Pereira
authors.affiliation: Professor, Department of Pediatric Dentistry and Orthodontics, Faculty of Dentistry, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, Minas Gerais, Brazil.
authors.forename: Leandro Silva
authors.initials: LS
authors.lastname: Marques
authors.affiliation: Professor, Department of Pediatric Dentistry and Orthodontics, Faculty of Dentistry, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, Minas Gerais, Brazil.
authors.forename: Joana
authors.initials: J
authors.lastname: Ramos-Jorge
authors.affiliation: Professor, Department of Oral Surgery and Pathology, Faculty of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Tarcília
authors.initials: T
authors.lastname: Aparecida da Silva
authors.affiliation: Professor, Department of Pediatric Dentistry and Orthodontics, Faculty of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Saul Martins
authors.initials: SM
authors.lastname: Paiva
mesh_terms: D000293:Adolescent; D000328:Adult; D001491:Basophils; D002648:Child; D004804:Eosinophils; D005260:Female; D005881:Gingiva / Q000187:drug effects* / Q000473:pathology; D006801:Humans; D006967:Hypersensitivity / Q000097:blood / Q000209:etiology* / Q000473:pathology / Q000517:prevention & control; D007073:Immunoglobulin E / Q000097:blood; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D009532:Nickel / Q000009:adverse effects*; D016910:Orthodontic Brackets / Q000009:adverse effects*; D010512:Periodontal Index; D055815:Young Adult
chemical_list: D007073:Immunoglobulin E; D009532:Nickel