title: A method for producing controlled fluoride release from an orthodontic bracket.
abstract: The aim of this study was to manufacture and test, in vitro, a novel modification to provide fluoride-releasing orthodontic brackets. Thirty-two orthodontic brackets were drilled to produce a recess (approximately 1.3 mm in diameter and 0.7 mm in depth) at the centre of the bracket base. Four materials, with and without the addition of sodium fluoride, a glass ionomer cement (Ketac Cem micro), a resin-modified glass ionomer cement (RMGIC; GC Fuji Ortho LC), a zinc phosphate (Zinc Cement Improved), and a resin (Transbond XT) were used to fill the recess in the bracket base. Fluoride release was measured daily during the first week and then weekly for 10 weeks. An ion chromatograph with suppressed conductivity was used for free fluoride ion determination. Statistical analysis to determine the amount of flouride release was undertaken using analysis of variance and Tukey's test. During the first 2 weeks, the resin group, with the addition of 38 per cent sodium fluoride added, released significantly more free fluoride (P < 0.05), but after 2 weeks the fluoride release markedly decreased. After 5 weeks, the RMGIC group, with 15 per cent added sodium fluoride, had significantly higher (P < 0.05) daily fluoride release than the other groups. The findings demonstrated that an appropriate fluoridated material can be used as a fluoride-releasing reservoir in a modified orthodontic bracket to enable it to release fluoride over the period of fixed appliance treatment.
authors.affiliation: Faculty of Stomatology, Capital University of Medical Sciences, People's Republic of China.
authors.forename: Song
authors.initials: S
authors.lastname: Li
authors.forename: Ross S
authors.initials: RS
authors.lastname: Hobson
authors.forename: Yuxing
authors.initials: Y
authors.lastname: Bai
authors.forename: Zhuoqun
authors.initials: Z
authors.lastname: Yan
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Carrick
authors.forename: John F
authors.initials: JF
authors.lastname: McCabe
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry; D002327:Cariostatic Agents / Q000737:chemistry*; D002852:Chromatography, Ion Exchange; D003692:Delayed-Action Preparations; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D008277:Magnesium Oxide / Q000737:chemistry; D008422:Materials Testing; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D011076:Polycarboxylate Cement / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D012969:Sodium Fluoride / Q000737:chemistry*; D013499:Surface Properties; D013997:Time Factors; D015034:Zinc Oxide / Q000737:chemistry; D015036:Zinc Phosphate Cement / Q000737:chemistry