Fluoride release and microhardness of one-step adhesives in two immersion solutions

Somphone Phanthavong, DDS, PhD,(a) Naoko Harada, DDS, PhD,(a) Hidekazu Sonoda, DDS, PhD,(a) Toru Nikaido, DDS, PhD,(a) Patricia N. R. Pereira, DDS, PhD,(b) and Junji Tagami, DDS, PhD(a,c)

(a)Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, (b)Department of Operative Dentistry, School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA, and (c)Center of Excellence Program for Frontier Research on Molecular Destruction and Reconstruction of Tooth and Bone, Tokyo Medical and Dental University, Tokyo, Japan



Purpose: To measure the amount of fluoride-release and microhardness of fluoride-releasing one-step adhesives; Xeno CF Bond, Reactmer Bond, and One-Up Bond F in two different solutions.
Materials and Methods: For fluoride-release measurement, five samples for each group were stored in deionized water or demineralizing solution for one day. A resin-modified glass ionomer cement, Fuji II LC (Improved), was used as a control. Fluoride ion release was analyzed with a fluoride ion-specific electrode. For microhardness measurement, the specimens prepared in the same manner as described above were stored in two different solutions or dry condition for one day. After dividing into halves, the microhardness of the specimen was measured using a nanoindentation tester.
Results: Amount of fluoride-release and microhardness of the adhesives were significantly different according to the immersion solutions and the materials. The adhesives demonstrated significantly less amounts of fluoride-release than that of Fuji II LC (Improved). Microhardness of the specimens immersed in solutions were significantly higher than those stored in dry condition for all the adhesives.
Conclusion: The amount of fluoride-release was significantly less than that of the resin-modified glass ionomer cement. Microhardness of the adhesives increased after 1-day storage in the media probably due to subsequent acid-base reaction and cross-linking of polymers. (Int Chin J Dent 2004; 4: 1-7.)

Clinical Significance
: Amount of fluoride-release and microhardness of the fluoride-containing adhesives were material and immersion solution dependent. The adhesives demonstrated the capacity for fluoride-release, although the amount of fluoride-release was significantly less than that of the resin-modified glass ionomer cement.
Key Words: fluoride-release, microhardness, one-step adhesives.