The aim of this study was to assess the fluoride (F) release potential of F-containing adhesives Transbond Plus (TB+), Light Bond (LBF), and Geristore-Tenure (GS), and a control adhesive without F content, Transbond XT (TBXT), in relation to microhardness (mu H) and degree of conversion (DC). Ten specimens of each adhesive system were illuminated at 1100 mW/cm(2) for 10 and 20 sec, totalling 80 samples. Fourier transform infrared spectroscopy was used for the assessment of DC. mu H was assessed before and after four-weeks of immersion in artificial saliva (pH 4.8) at 37 degrees C. The amount of F release was monitored by a F ion-selective electrode. F release was related to adhesive system type and curing time (p<0.05) and decreased in the following order, with the subscript indicating the illumination time in sec: TB+(10)>TB+(20)>GS(10)>GS(20)>LBF10>LBF20. The decrease of mu H after four weeks of immersion in artificial saliva is related to increased release of F (r=0.651; p<0.001). TB+ had significantly superior white spot lesions preventive potential due to twice higher F ions release, but its high mu H changes raise concerns of bond strength properties. The tested materials showed low F recharge potential.
