title: In vitro and in vivo assessment of a glass slow fluoride releasing device: a pilot study.
abstract: OBJECTIVE
  The aims were to evaluate a) whether a slow release fluoride-glass pellet (SFG) would be retained in the mouth and release fluoride (F) over a long period of time, b) what concentrations of F in the glass would provide ideal intra-oral saliva F concentrations and c) whether an SFG would affect blood plasma concentrations of F after swallowing compared with ingestion of a commercial NaF tablet.
  
  
  METHODS
  a) A prototype SFG was attached to a maxillary molar of a volunteer. Baseline saliva F concentrations were measured prior to glass placement, daily in week one; one day a week for weeks two to three and then one day a month up to 18 months. Four subjects had the SFG for six months with saliva F concentration assessments at periodic intervals. b) SFGs containing F at 13.3%, 18.3% and 21.9%, and an improved solubility, were tested using three volunteers and saliva F concentrations measured. c) Five volunteers each swallowed either a SFG or a NaF tablet. Blood plasma samples were taken at baseline and F measured at time intervals of 2.5, 5, 10, 20, 30, 45, 60, 90 and 120 mins post-ingestion.
  
  
  RESULTS
  a) The prototype SFG were successfully retained and released F into saliva; mean concentrations of 0.035 mg L(-1) were achieved lasting for over 18 months. Overall saliva F concentrations were approximately doubled. Analysis of the pellet at the end of use showed it still contained some F possibly indicating a recharging effect. b) The 13.3% F concentration SFG produced significantly higher saliva F levels than the two other concentrations tested. The two higher concentration F glasses contained aluminium as part of the formulation of the glass structure, which is known to bind F whereas the 13.3% glass contained F alone. c) While blood plasma F levels increased after ingestion of the NaF tablet there was no increase in F when the SFG was swallowed.
  
  
  CONCLUSIONS
  A slow release F containing glass device showed promise as a means to enhance intra-oral F saliva concentration.
authors.affiliation: Department of Paediatric Dentistry, Leeds Dental Institute, Clarendon Way, Leeds LS2 9LU, England, UK.
authors.forename: M E J
authors.initials: ME
authors.lastname: Curzon
authors.forename: K J
authors.initials: KJ
authors.lastname: Toumba
mesh_terms: D000328:Adult; D002327:Cariostatic Agents / Q000008:administration & dosage* / Q000032:analysis; D003679:Deglutition; D003692:Delayed-Action Preparations; D005459:Fluorides / Q000008:administration & dosage* / Q000032:analysis / Q000097:blood; D005898:Glass; D006801:Humans; D012463:Saliva / Q000737:chemistry*
chemical_list: D002327:Cariostatic Agents; D003692:Delayed-Action Preparations; D005459:Fluorides