Assessing the Fluoride Uptake Level of the Enamel by a Fluoride Varnish and a Fluoride Gel (APF)

Statement of Problem: Various forms of fluoride-contained products are used to increase the resistance of the tooth against caries for preventive purposes. Furthermore, studies demonstrated higher fluoride uptake with varnish and gel among the wide range of products.

This study compared fluoride uptake of Duraflor® varnish (Practicon Dent, USA) with fluoride gel (APF, Sultan®), used on the enamel surface of the intact teeth.

In this experimental in-vitro study, 20 intact pre-molar teeth extracted for orthodontic purposes were randomly assigned to two groups of 10 teeth. The teeth were sectioned into two mesial and distal halves as the control and experimental sides. Defined semi-circular areas on the enamel surface of the experimental halves were treated with gel or varnish for 1 hour. The sample halves were stored in artificial saliva for 24 hours at 37°c, etched for 30 seconds by 0.5 M perchloric acid, and washed by 0.2 m KOH after each etching process. Biopsies of the samples were obtained by Acid Etch Enamel Biopsy technique and the fluoride and calcium concentrations were calculated by potentiometer and spectrophotometer, respectively. Kolmogorov-smirnov, Paired t-test and Student t- test were used for statistical analyses.

The results demonstrated an increase in the enamel fluoride content after exposure of the teeth to both Duraflor® varnish and APF gel (Sultan®). The results of the paired t-test revealed significant differences between the experimental and control halves in both groups (varnish: p =0.002, gel: p =0.039). The fluoride uptake value in varnish and gel groups was 2069.78 ppm and 1050.99 ppm, respectively. The student t-test showed a statistically significant difference (p =0.01).

Both APF gel and Duraflor® varnish increased the fluoride content of the tooth enamel after application, although Duraflor® varnish had a higher fluoride uptake level than APF gel.