title: Osteocalcin and N-telopeptides of type I collagen marker levels in gingival crevicular fluid during different stages of orthodontic tooth movement.
abstract: BACKGROUND
  The aim of the study was to quantitatively and qualitatively analyze changes in the gingival crevicular fluid (GCF) during orthodontic movement by assessing the levels of cross-linked N-telopeptides of type I collagen marker (NTx) and osteocalcin (OC) activity.
  
  
  METHODS
  Twenty patients requiring all first premolars to be extracted were selected and treated with conventional straight-wire mechanotherapy. The canines were retracted with closed-coil springs. The maxillary canine on one side acted as the experimental site, and the contralateral canine was the control. GCF was collected from around the canines before retraction, and 1 hour, 1 day, 7 days, 14 days, and 21 days after retraction. GCF NTx and OC levels were estimated and compared with the control side.
  
  
  RESULTS
  The results showed statistically significant changes in NTx and OC levels on days 7, 14, and 21 when we compared the experimental and control sides. The peak in all activity of the variables occurred on day 14 after retraction.
  
  
  CONCLUSIONS
  The study showed that NTx and OC levels can be successfully estimated in the GCF, and its increased levels might indicate the active tooth movement phase in orthodontic therapy.
authors.affiliation: Department of Pediatric Dentistry and Orthodontics, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Alfaqeeh
authors.forename: Sukumaran
authors.initials: S
authors.lastname: Anil
mesh_terms: D000293:Adolescent; D000328:Adult; D001641:Bicuspid / Q000601:surgery; D024042:Collagen Type I / Q000032:analysis*; D003481:Cuspid / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D005883:Gingival Crevicular Fluid / Q000737:chemistry*; D006801:Humans; D008297:Male; D008311:Malocclusion, Angle Class I / Q000628:therapy; D008437:Maxilla; D052280:Orthodontic Anchorage Procedures; D019516:Orthodontic Space Closure; D009969:Orthodontic Wires; D015675:Osteocalcin / Q000032:analysis*; D010455:Peptides / Q000032:analysis*; D012690:Serial Extraction; D014087:Tooth Movement Techniques / Q000145:classification*; D055815:Young Adult
chemical_list: D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin