FA Crystal/Eudragit Laminate for Repair of Carious and Eroded Enamel

Objectives: 1. Determine the maximum flurorapatite crystal (FA) fill of the Eudragit (Eu) laminate that maintained its flexibility and bonding to enamel.
2. Measure the release of Fluoride from the FA/Eu laminate at neutral and acidic pH.
3. Determine the remineralization ability of FA/Eu laminate on artificial enamel lesion.
Methods: The FA crystals were synthesized according to Chen et al and mixed with Eudragit E100 for this study.
Fluoride release from the filled and non-filled FA/Eu laminate was measured at pH 7 and 4 using a Fluoride electrode at 1 day, 1 week 2 weeks and 1 month. Artificial carious lesions were created in enamel and randomly divided into two treatment groups: laminates with FA (N=10) and laminates without FA (N=10). The filled and non-filled laminates were treated with alcohol, molded to the enamel surface and then cycled at pH 4 (1 hour) and pH 7 (23 hours) per day in artificial saliva for 3 days. Enamel microhardness measurements (SMH) were obtained for sound, demineralized and after application of the laminate for each group.
Results:
After incremental FA fills, the 40% wt. FA filled laminate maintained good flexibility and bonding to enamel.
Fluoride release from FA/Eu laminate was minimal at pH7. Fluoride release from FA/Eu laminate at pH4 was 1 day 0.58, 1 week 1.02, 2 weeks 0.49 and 1 month 0.44 ppm.
Post treatment SMH values showed an increase in hardness of the demineralized enamel for the filled laminate but not for the non-filled. This increase in microhardness did not achieve that of sound enamel.
Conclusions:
The fluoride release overtime from this novel flexible laminate which can be molded to any tooth surface and tinted to any tooth color; and the increase microharrdness of the demineralized enamel makes this FA/Eu laminate ideal for the repair of carious and eroded enamel surfaces.