title: Metal and ceramic bracket effects on human buccal mucosa epithelial cells.
abstract: OBJECTIVE
  To test the null hypothesis that metal and ceramic brackets have no effect on the epithelial cells of the buccal mucosa.
  
  
  METHODS
  Two metal and two ceramic brackets were bonded in 21 individuals of both sexes. With the use of liquid-based exfoliative cytology, morphometric and morphologic changes in buccal mucosa cells adjacent to these brackets were determined and were compared at three time points: baseline (T0), 60 days after placement (T1), and 30 days after removal of the brackets (T2).
  
  
  RESULTS
  A decrease in nuclear area and an increase in cytoplasmic area occurred in the buccal mucosa cells adjacent to the brackets at T1 (P < .01). At T2, this altered morphometry persisted only in cells adjacent to the metal brackets, although to a lesser degree than at T1 (P < .01). A greater decrease in nuclear area was noted in cells adjacent to the metal brackets than in those next to the ceramic brackets (P < .01). At T0, the proportions of surface and subsurface cells were similar, but at T1, a predominance of surface cells was observed (P < .05). At all time points, smears of cells appeared normal or normal with some inflammatory changes.
  
  
  CONCLUSIONS
  The hypothesis is rejected. Placement of metal and ceramic brackets in the buccal cavity induces cellular alterations. These alterations do not suggest malignancy.
authors.affiliation: Pontifical Catholic University of Parana, Curitiba, Brazil.
authors.forename: Betina R
authors.initials: BR
authors.lastname: Pereira
authors.forename: Orlando M
authors.initials: OM
authors.lastname: Tanaka
authors.forename: Antônio A S
authors.initials: AA
authors.lastname: Lima
authors.forename: Odilon
authors.initials: O
authors.lastname: Guariza-Filho
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Maruo
authors.forename: Elisa S
authors.initials: ES
authors.lastname: Camargo
mesh_terms: D000293:Adolescent; D000328:Adult; D001641:Bicuspid; D002467:Cell Nucleus / Q000473:pathology; D048430:Cell Shape; D002516:Ceramics / Q000737:chemistry*; D002648:Child; D004396:Coloring Agents; D003581:Cytodiagnosis; D003593:Cytoplasm / Q000473:pathology; D003722:Dental Alloys / Q000737:chemistry*; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry*; D004847:Epithelial Cells / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008422:Materials Testing; D008437:Maxilla; D008875:Middle Aged; D008963:Molar; D009061:Mouth Mucosa / Q000473:pathology*; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D019279:Resin Cements / Q000737:chemistry; D013280:Stomatitis / Q000473:pathology; D014094:Tooth, Deciduous; D055815:Young Adult
chemical_list: D004396:Coloring Agents; D003722:Dental Alloys; D003764:Dental Materials; D019279:Resin Cements; C477790:Transbond XT