title: Demineralization properties of newly erupted and mature premolars around orthodontic brackets: an in-vivo study.
abstract: BACKGROUND
  The aims of this study were to evaluate the in-vivo reaction of newly erupted enamel to demineralization around orthodontic brackets and to compare it with that of mature enamel.
  
  
  METHODS
  Thirteen orthodontic patients scheduled to have 4 first premolars extracted for orthodontic reasons were divided into 2 groups. Group 1 included 7 younger patients with newly erupted teeth (4 boys, 3 girls; mean age, 11.21 +/- 1.12 years; range, 11-13 years). Group 2 contained 6 adults with mature teeth (5 men, 1 woman; mean age, 34.64 +/- 4.01 years; range, 25-41 years). Brackets were placed, and, 30 days later, the teeth were extracted. These teeth were longitudinally sectioned, and demineralization was assessed by cross-sectional microhardness. Determinations were made at the bracket-edge composite limits and at occlusal and cervical points 100 mum away. Evaluations under the brackets and at the lingual surfaces were made as controls. In all these positions, 6 indentations were made at depths from 10 to 90 mum from the enamel surface. Analysis of variance (ANOVA) and Tukey tests were used for statistical evaluation at the P <0.05 level.
  
  
  RESULTS
  ANOVA showed statistically significant differences for tooth type, position, depth, and their interactions (P <0.05), except the tooth type and position interaction. The multiple comparison test showed less demineralization in the enamel around orthodontic brackets bonded to mature teeth campared with newly erupted teeth (P <0.05).
  
  
  CONCLUSIONS
  During the 30-day study period, the tooth enamel in the adult orthodontic patients was more resistant to demineralization than that of the younger patients.
authors.affiliation: Department of Orthodontics, Faculty of Dentistry, Erciyes University, Kayseri, Turkey; visiting professor, King Saud University, Riyadh, Saudi Arabia. tancanuysal@yahoo.com
authors.forename: Tancan
authors.initials: T
authors.lastname: Uysal
authors.forename: Mihri
authors.initials: M
authors.lastname: Amasyali
authors.forename: Suat
authors.initials: S
authors.lastname: Ozcan
authors.forename: Deniz
authors.initials: D
authors.lastname: Sagdic
mesh_terms: D000134:Acid Etching, Dental; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001641:Bicuspid / Q000473:pathology* / Q000503:physiopathology; D002648:Child; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003743:Dental Enamel / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D006244:Hardness; D006801:Humans; D008297:Male; D016910:Orthodontic Brackets; D019279:Resin Cements / Q000737:chemistry; D016037:Single-Blind Method; D019237:Tooth Cervix / Q000473:pathology; D019228:Tooth Crown / Q000473:pathology; D017001:Tooth Demineralization / Q000473:pathology* / Q000503:physiopathology; D014078:Tooth Eruption / Q000502:physiology*
chemical_list: D003188:Composite Resins; D019279:Resin Cements; C477790:Transbond XT; C516047:Transbond XT Light Cure Adhesive Primer