title: Effect of fluoride on root resorption following heavy and light orthodontic force application for 4 weeks and 12 weeks of retention.
abstract: OBJECTIVE
  To evaluate the null hypothesis that fluoride intake via drinking water has no effect on orthodontic root resorption in humans after orthodontic force application for 4 weeks and 12 weeks of retention.
  
  
  METHODS
  Forty-eight patients who required maxillary premolar extractions as part of their orthodontic treatment were selected from two cities in Turkey. These cities had a high and low fluoride concentration in public water of ≥2 pm and ≤0.05 pm, respectively. The patients were randomly separated into four groups of 12 each: group 1HH, high fluoride (≥2 ppm) and heavy force (225 g); group 2LH, low fluoride (≤0.05 ppm) and heavy force; group 3HL, high fluoride and light force (25 g); and group 4LL, low fluoride and light force. Light or heavy buccal tipping force was applied on the upper first premolars for 28 days. At day 28, the left premolars were extracted (positive control side); the right premolars (experimental side) were extracted after 12 weeks of retention. The samples were analyzed with microcomputed tomography.
  
  
  RESULTS
  On the positive control side, under heavy force application, the high fluoride groups exhibited less root resorption (P  =  .015). On the experimental side, it was found that fluoride reduced the total volume of root resorption craters; however, this effect was not statistically significant (P  =  .237). Moreover, the results revealed that under heavy force application experimental teeth exhibited more root resorption than positive control groups.
  
  
  CONCLUSIONS
  The null hypothesis could not be rejected. High fluoride intake from public water did not have a beneficial effect on the severity of root resorption after a 4-week orthodontic force application and 12 weeks of passive retention.
authors.affiliation: Department of Orthodontics, Faculty of Dentistry, Karadeniz Technical University, Trabzon, Turkey.
authors.forename: Ersan I
authors.initials: EI
authors.lastname: Karadeniz
authors.forename: Carmen
authors.initials: C
authors.lastname: Gonzales
authors.forename: Tamer
authors.initials: T
authors.lastname: Turk
authors.forename: Devrim
authors.initials: D
authors.lastname: Isci
authors.forename: Aynur M
authors.initials: AM
authors.lastname: Sahin-Saglam
authors.forename: Huseyin
authors.initials: H
authors.lastname: Alkis
authors.forename: Selma
authors.initials: S
authors.lastname: Elekdag-Turk
authors.forename: M Ali
authors.initials: MA
authors.lastname: Darendeliler
mesh_terms: D000293:Adolescent; D002648:Child; D060766:Drinking Water / Q000737:chemistry*; D005260:Female; D005459:Fluorides / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D009971:Orthodontics, Corrective / Q000295:instrumentation / Q000379:methods*; D012391:Root Resorption / Q000188:drug therapy* / Q000473:pathology; D055114:X-Ray Microtomography; D055815:Young Adult
chemical_list: D060766:Drinking Water; D005459:Fluorides