title: Tooth movement and cytokines in gingival crevicular fluid and whole blood in growing and adult subjects.
abstract: BACKGROUND
  Tooth movement has been studied largely with respect to the force required for tipping when pressure distribution varies along the length of the periodontal ligament. But important factors for effective canine translation include the nature and magnitude of applied stress and the patient's cell biology. The purpose of this research was to test 3 hypotheses: (1) the velocity of tooth translation (v(t)) is related to applied stress and growth status, (2) a threshold of stress accounts for the lag phase, and (3) v(t) is correlated with the ratio (AI) of 2 cytokines (IL-1beta, IL-1RA) measured in gingival crevicular fluid (GCF) and stimulated whole blood (SWB).
  
  
  METHODS
  Continuous maxillary canine retraction stresses of 13 kPa and 4, 26, or 52 kPa were applied bilaterally in 6 growing and 4 adult subjects for 84 days. Dental models and GCF samples were collected at 1- to 14-day intervals. Cytokines were measured in GCF and SWB cell cultures.
  
  
  RESULTS
  V(t) was positively related to stress and was higher in growing subjects (P = .001). It was also related to AI(GCF) in growers (R2= 0.56) and nongrowers (R2= 0.72). Canines moved with 52 kPa showed a lag phase, and postlag phase AI(GCF) was twice that of lag phase AI(GCF). Mean v(t) and associated AI(GCF) during the postlag phase were nearly double the values for canines moved with 13 and 26 kPa. SWB production of cytokines was dose-dependent. For growing subjects, SWB IL-1RA was correlated with v(t) (R = 0.70-0.72), and AI(SWB) and IL-1beta concentrations were correlated with AI(GCF) (R = 0.73-0.78).
  
  
  CONCLUSIONS
  V(t) varied with growth status and stresses < or = 52 kPa; stresses of < 52 kPa showed no lag phase; and equivalent stresses yielded subject-dependent differences in v(t), which correlated with cytokines in GCF and SWB.
authors.affiliation: Department of Oral Biology and Department of Growth and Development, University of Nebraska Medical Center, College of Dentistry, Lincoln, NE 68583-0755, USA. liwasaki@unmc.edu
authors.forename: Laura R
authors.initials: LR
authors.lastname: Iwasaki
authors.forename: Larry D
authors.initials: LD
authors.lastname: Crouch
authors.forename: Albert
authors.initials: A
authors.lastname: Tutor
authors.forename: Scott
authors.initials: S
authors.lastname: Gibson
authors.forename: Navin
authors.initials: N
authors.lastname: Hukmani
authors.forename: David B
authors.initials: DB
authors.lastname: Marx
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Nickel
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003481:Cuspid / Q000502:physiology*; D016207:Cytokines / Q000097:blood / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D005883:Gingival Crevicular Fluid / Q000502:physiology*; D006801:Humans; D008297:Male; D008437:Maxilla / Q000254:growth & development; D008445:Maxillofacial Development / Q000502:physiology*; D013314:Stress, Mechanical; D014087:Tooth Movement Techniques / Q000379:methods*
chemical_list: D016207:Cytokines