title: Effects of accentuated and reversed curve of Spee on apical root resorption.
abstract: BACKGROUND
  In this study, we evaluated the influence of intrusion mechanics with accentuated and reversed curve of Spee on root resorption of the maxillary and mandibular incisors.
  
  
  METHODS
  A sample of 60 patients with Class I and Class II Division 1 malocclusions having nonextraction treatment was divided into 2 groups with the following characteristics: group 1 comprised 30 deepbite patients, treated with accentuated and reversed curve of Spee intrusion mechanics, with an initial mean age of 12.8 +/- 1.23 years (range, 10.01-15.32 years), and group 2 comprised 30 patients with normal overbite treated without intrusion mechanics, with an initial mean age of 12.87 +/- 1.43 years (range, 10.02-15.36 years). Pretreatment and posttreatment periapical radiographs were used to evaluate root resorption. The groups were compared by using the Mann-Whitney U test. Correlation between root resorption and tooth movement was investigated with the Spearman correlation coefficient.
  
  
  RESULTS
  The deepbite group treated with accentuated and reversed curve of Spee had statistically greater root resorption (1.87) than the normal overbite group (1.54), at P = .017. Changes in overbite and vertical displacements of the maxillary central incisor apices had significant correlations to root resorption (r = 0.30, P = .019; r = 0.27, P = .037, respectively).
  
  
  CONCLUSIONS
  Accentuating and reversing the curve of Spee in the archwires to correct deep overbite causes more root resorption than nonintrusive mechanics.
authors.affiliation: Department of Orthodontics, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil. kellychiqueto@yahoo.com.br
authors.forename: Kelly
authors.initials: K
authors.lastname: Chiqueto
authors.forename: Décio Rodrigues
authors.initials: DR
authors.lastname: Martins
authors.forename: Guilherme
authors.initials: G
authors.lastname: Janson
mesh_terms: D000293:Adolescent; D002508:Cephalometry; D002648:Child; D003724:Dental Arch; D005260:Female; D006801:Humans; D007180:Incisor / Q000473:pathology*; D008297:Male; D008310:Malocclusion / Q000628:therapy*; D009969:Orthodontic Wires / Q000009:adverse effects*; D009971:Orthodontics, Corrective / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D018024:Peer Review, Health Care; D012189:Retrospective Studies; D012391:Root Resorption / Q000209:etiology*; D018709:Statistics, Nonparametric; D014716:Vertical Dimension