In vitro evaluation of fluoride release of orthodontic bonding adhesives.

AIM

To assess the fluoride release from adhesives used for bonding in orthodontics.

METHODS

Six bonding agents were evaluated: five adhesives (Biofix, Fill Magic Orthodontic, EagleBond, Orthobond, and Transbond XT) and one resin-reinforced glass-ionomer cement (Fuji Ortho LC), the latter serving as a control. Ten samples of each adhesive were stored in containers with 5 mL of deionized distilled water at 37°C. Fluoride release was measured with an ion-specific electrode. Readings were taken periodically for a total of 33 days. On day 28, all samples were immersed in a 0.221% sodium fluoride solution for 5 minutes to assess their recharge potential. Descriptive statistics were calculated for the fluoride release rates of each material. ANOVA with multiple comparisons and the Kruskal-Wallis tests (P < .05) were used to assess differences between the groups.

RESULTS

All adhesives released significant amounts of fluoride (P < .05). During the first day, Biofix released the highest amount of fluoride, followed by Fuji Ortho LC, which also showed the highest fluoride release from day 7 to day 33. The fluoride release from Biofix and Fuji Ortho LC decreased by the third day to 40% of its original value. All other adhesives maintained their fluoride release with only small fluctuations.

CONCLUSION

All the materials released significant amounts of fluoride, with Biofix having the highest release in the first 3 days and Fuji Ortho LC over the total length of the experiment.