title: Fluoridated elastomers: in vivo versus in vitro fluoride release.
abstract: OBJECTIVE
  To compare (i) the in vivo release of fluoride from fluoridated elastomers to the in vitro release, and (ii) the residual fluoride content of the elastomers after 1 week in the mouth with and without fluoride toothpaste and mouthrinse.
  
  
  METHODS
  A prospective, longitudinal, cross-over study.
  
  
  METHODS
  Six subjects were recruited by poster to take part in the study. Each subject had one premolar in each quadrant to which a bracket could be fixed and exemplary oral hygiene. Elastomers were then placed on these brackets.
  
  
  METHODS
  The study was divided into two parts: (i) subjects used oral hygiene products with fluoride and (ii) oral hygiene products with fluoride were excluded. Both groups of elastomers were left in the mouth for 1 week. After collection the elastomers were stored in distilled water.
  
  
  METHODS
  The amount of residual fluoride in the ligatures after they have been placed in the mouth for 1 week was compared with the cumulative fluoride release in vitro over 1 week and 6 months.
  
  
  RESULTS
  Only 13 per cent of the total amount of fluoride in fluoridated elastomers was released during the first week in vitro, compared with 90 per cent in vivo. There was a significantly greater amount (P = 0.001) of residual fluoride when the elastomers were in the mouth for 1 week in the presence of fluoride toothpaste and mouthrinse, than when fluoride supplements were excluded.
  
  
  CONCLUSIONS
  (1) Higher levels of fluoride are lost from the fluoride elastomers in vivo than in vitro during the first week. (2) A significantly greater amount of residual fluoride was released from the elastomers placed in the mouth when fluoride toothpaste and mouthrinse were used.
authors.affiliation: Charles Clifford Dental Hospital, Sheffield, and Chesterfield Royal Hospital, UK. dtinsley.harrogate@virgin.net
authors.forename: D
authors.initials: D
authors.lastname: Tinsley
authors.forename: J J
authors.initials: JJ
authors.lastname: O'Dwyer
authors.forename: Philip E
authors.initials: PE
authors.lastname: Benson
mesh_terms: D002327:Cariostatic Agents / Q000008:administration & dosage*; D018592:Cross-Over Studies; D020724:Elastomers / Q000737:chemistry*; D005260:Female; D005459:Fluorides / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D016910:Orthodontic Brackets; D011446:Prospective Studies
chemical_list: D002327:Cariostatic Agents; D020724:Elastomers; D005459:Fluorides