The uptake and release of fluoride by ion-leaching cements after exposure to toothpaste.
OBJECTIVE
The cariostatic action associated with the glass-ionomer cement (GIC) is usually attributed to its sustained release of fluoride. However the ability of the GIC to act as a fluoride reservoir, taking it up from an external source (e.g. toothpaste, mouthwash) and subsequently releasing it over time, may also be a contributory factor. This study investigated the reservoir effect of various recently introduced ion-releasing cements: two resin-modified glass-ionomer cements (Fuji II LC, Vitremer), a compomer (acid-modified composite resin) (Dyract), and a recently introduced conventional glass-ionomer (Fuji IX).


METHODS
Specimens were exposed to a fluoridated toothpaste after 28 and/or 58 days. The release of fluoride into the storage water, both before and after exposure, was monitored using a differential electrode cell.


RESULTS
There was no significant difference in the fluoride releases from Vitremer and Fuji II LC. These materials released significantly more fluoride than Fuji IX and Dyract. All the materials released more fluoride on the day after exposure to an external fluoride source compared with the day before exposure. Release rates returned to baseline within 3 days. Within the time periods of the study, only the uptake/re-release of Fuji IX was adversely affected by late exposure. All the materials showed an enhanced uptake and release on repeated exposure to the external fluoride source.


CONCLUSIONS
All the materials under test (Dyract, Fuji II LC, Vitremer and Fuji IX) released significant amounts of fluoride and reacted positively to exposure to an external fluoride source.
Rothwell
M
M
Biomaterials Department, Eastman Dental Institute, London, UK.
Anstice
H M
HM
Pearson
G J
GJ
D002327:Cariostatic Agents / Q000032:analysis / Q000737:chemistry*; D020770:Compomers; D003188:Composite Resins / Q000737:chemistry; D003692:Delayed-Action Preparations; D005459:Fluorides / Q000032:analysis / Q000737:chemistry*; D005899:Glass Ionomer Cements / Q000737:chemistry*; D017736:Ion-Selective Electrodes; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D009067:Mouthwashes / Q000737:chemistry; D012117:Resins, Synthetic / Q000737:chemistry; D017640:Silicates / Q000737:chemistry; D013997:Time Factors; D014100:Toothpastes; D014867:Water / Q000737:chemistry
D002327:Cariostatic Agents; D020770:Compomers; D003188:Composite Resins; D003692:Delayed-Action Preparations; C088486:Dyract; C079765:Fuji II LC cement; D005899:Glass Ionomer Cements; D008689:Methacrylates; D009067:Mouthwashes; D012117:Resins, Synthetic; D017640:Silicates; D014100:Toothpastes; C084550:Vitremer; C110713:fuji IX; D014867:Water; D005459:Fluorides