Fluoride release and recharge potential of remineralizing orthodontic adhesive systems.

The aim of this study was to assess the fluoride (F) release potential of Fcontaining 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 (μH) and degree of conversion (DC). Ten specimens of each adhesive system were illuminated at 1100 mW/cm2 for 10 and 20 sec, totalling 80 samples. Fourier transform infrared spectroscopy was used for the assessment of DC. μH was assessed before and after four-weeks of immersion in artificial saliva (pH 4.8) at 37°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>GS10 >GS20>LBF10>LBF20. The decrease of μH 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 μH changes raise concerns of bond strength properties. The tested materials showed low F recharge potential.