Effect of Multiple NaF Varnish Applications on Five Different Restoratives

Objective: The objective of this work was to ascertain the effect of three sequential applications of a Sodium fluoride (NaF) varnish on the translucency, color and surface roughness of four different classes of restorative materials including: conventional glass-ionomer,compomer, nano-hybrid composite, and flowable composite.

Method: Five 11mmx2mm specimens of each restorative material were prepared in a silicone mold according to the manufacturer’s specifications.  In each group there were two controls and three subject specimens. All were stored in distilled water at 37⁰ C. The specimens were treated with 5% neutral sodium fluoride varnish and returned to the distilled water at 37⁰ C for 24 hours. The varnish was then removed using a wear tester modified for controlled brushing with toothbrush heads mounted t and lowered perpendicular to the surface of the specimen. The specimens were brushed for 5 minutes at 100 cycles per minute with a force of 500 grams under water. The control specimens were treated in the same manner except for varnish application. After each varnish treatment, color and roughness measurements were taken. The process was repeated for three varnish treatments. Color measurements were made using the CIE L*a*b* color system. Translucency and color change (ΔE*) values after each treatment were calculated. Change in surface roughness of the specimens was measured using confocal microscopy. Five different surfaces on each specimen were scanned to produce 3D images for determining roughness values (Ra) after each treatment.

Result: Translucency, ΔE* and Ra values for each treatment were compared using ANOVA and the Tukey test (p=0.05).  There was no statistically significant change in translucency, color or roughness for the different materials in the test or control groups for any time period.

Conclusion: Three sequential applications of NaF varnish did not significantly change translucency, color or surface roughness of five different common restorative materials.