title: Physical properties of root cementum: part 15. Analysis of elemental composition by using proton-induced x-ray and gamma-ray emissions in orthodontically induced root resorption craters of rat molar cementum after exposure to systemic fluoride.
abstract: BACKGROUND
  Root resorption resulting from orthodontic treatment is an unpredictable adverse effect. Literature examining the potential protective influence of tooth cementum minerals against orthodontically induced inflammatory root resorption has been sparse. Fluorine could have a role in minimizing the extent and severity of resorptive lesions. The purpose of this study was to examine the elemental content of tooth cementum in orthodontically induced inflammatory root resorption lesions and the effect of systemic fluoride.
  
  
  METHODS
  Twenty 7-week-old Wistar rats were divided into 2 groups of 10 and exposed to systemic fluoride (100 ppm) or nonfluoridated drinking water for 2 weeks. Orthodontic tooth movement was implemented with a nickel-titanitum closing coil with a force of 100 g. The molars were then extracted, dissected, and prepared for cross-sectioning through the largest mesial midroot crater. The samples were mounted and scanned by using the Commonwealth Scientific and Industrial Research Organisation and the Australian Research Council's National Key for Geochemical Evolution and Metallogeny of Continents Nuclear Microprobe (Melbourne, Victoria, Australia). Analysis of variance (ANOVA) was used for statistical comparison of the elements and to determine the effect of fluoride, and unaffected tooth structure compared with root resorption craters. The Student t test was used to compare root crater lengths and depths of the fluoride vs no-fluoride groups.
  
  
  RESULTS
  Root resorption lesions of the group exposed to fluoride were significantly reduced in length and depth (P <0.01). The mineral content of the root resorption craters of the fluoride group had higher concentrations of fluorine and zinc (P <0.01). There was less calcium in the craters of the no-fluoride group compared with the fluoride group (P <0.05).
  
  
  CONCLUSIONS
  Cementum quality (influenced by systemic fluoride exposure) might impact the extent of orthodontically induced resorptive defects.
authors.affiliation: Nuclear Microprobe Applications Exploration and Mining, Commonwealth Scientific and Industrial Research Organisation (CSIRO), MARC, School of Physics, University of Melbourne, Melbourne, Australia.
authors.forename: Elaine
authors.initials: E
authors.lastname: Lim
authors.forename: David
authors.initials: D
authors.lastname: Belton
authors.forename: Peter
authors.initials: P
authors.lastname: Petocz
authors.forename: Manish
authors.initials: M
authors.lastname: Arora
authors.forename: Lam L
authors.initials: LL
authors.lastname: Cheng
authors.forename: M Ali
authors.initials: MA
authors.lastname: Darendeliler
mesh_terms: D000818:Animals; D002118:Calcium / Q000032:analysis; D003739:Dental Cementum / Q000737:chemistry* / Q000473:pathology / Q000502:physiology; D005260:Female; D005457:Fluoridation; D005459:Fluorides / Q000008:administration & dosage* / Q000032:analysis; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D012391:Root Resorption / Q000209:etiology / Q000473:pathology* / Q000517:prevention & control; D012964:Sodium / Q000032:analysis; D013051:Spectrometry, Gamma; D013052:Spectrometry, X-Ray Emission; D014087:Tooth Movement Techniques / Q000009:adverse effects*; D014131:Trace Elements / Q000032:analysis; D015032:Zinc / Q000032:analysis
chemical_list: D014131:Trace Elements; D012964:Sodium; D015032:Zinc; D005459:Fluorides; D002118:Calcium