In vitro investigation of aluminum and fluoride release from compomers, conventional and resin-modified glass-ionomer cements: A standardized approach

The amount of fluoride release from dental cements necessary for an anticar iogenic effect is nor established; moreover, the possible toxic effects due to high fluoride and aluminum release are not well known and the results a re still controversial. The aim of our study was to evaluate fluoride (F) a nd aluminum (Al) release from dental cements using a 'standardized approach ' according to the end-use of the materials, i.e, biocompatibility testing. Two polyacid-modified resin composites of recent application, commonly cal led compomers (Dyract(R) and Dyract Cem(R)), were compared with two convent ional acid-based (Fuji I(TM), Ketac-Cem(R)) and two resin-modified (Vitreme r(TM), Vitrebond(TM)) glass-ionomer cements (GICs). All types of cement are used in dentistry and are commercially available. Extracts of the cements into minimum essential medium, after setting over a 1-h (group A) and 1-wee k (group B) period, were performed. The extraction conditions were rigorous ly standardized. Mean values +/- standard deviation of F- and Al-levels in such extracts were measured and were expressed as mu g g(-1) (micrograms of ions per gram of cement). A great difference in the amount of ion release, both F and Al, was shown a mong the tested materials. The GICs, as well as Ketac-Cem(R), released more F and Al than the compomers. All of the materials released the greatest pr oportion of ions when the extraction was performed in the first hour after mixing (group A). Al- and F-values showed a highly significant positive cor relation, independently from the curing time. We conclude that the biological assessment of dental cements can be perform ed only if a pre-evaluation of the leachables is obtained by applying a sta ndardized protocol which allows a useful comparison between the different m aterials.