• Em-on Benjavongkulchai, Ph.D.
• Suphot Tamsailom, D.D.S, M.Sc., Diplomate, Thai Board (Periodontology)

Objective To evaluate the effect of fluoride/zinc/essential oil-containing mouthrinse on fluoride
uptake and microhardness in enamel.

Materials and methods A double-blind randomized trial was performed. Thirty polished bovine
enamel specimens (6 x 6 mm) were subjected to caries-likes lesion formation in the demineralizing
solution. Then specimens were analyzed for microhardness (no difference in microhardness; p > 0.05)
and divided into 3 groups (n=10/group). The fluoride and calcium contents in enamel were analyzed
by fluoride electrode and atomic absorption spectrometer, respectively. The specimens in three groups
were then treated with either fluoride/zinc/essential oil-containing mouthrinse (Listerine Total
Care-LTC), 100 ppm NaF (positive control), or 5% ethanol (negative control) and subjected to 30
cycles of demineralization/remineralization ie. 10 min in demineralizing solution, 5 min in test
solution, and 60 min in remineralizing solution. After the cycling, the fluoride, calcium and microhardness
in enamel were determined. The changes of fluoride content (Δ F) and microhardness (Δ H) after
treatment were analyzed between groups using a one way ANOVA and Tukey test.

Results The Δ F obtained from the test mouthrinse (71.10 ± 45.50 ppm) was not statistically different
(p > 0.05) from that of 100 ppm NaF (41.41 ± 26.75 ppm). However, both solutions showed significantly
more fluoride uptake than 5% ethanol group (0.20 ± 2.30 ppm) (p < 0.05). The Δ H of LTC
treated enamel (6.7 ± 2.8 Vickers) was not different (p > 0.05) from that of 100 ppm NaF treated
samples (10.9 ± 6.1 Vickers). However, Δ Hs of both treatments were significantly more than in ethanol
treated teeth (1.1 ± 1.7 Vickers) (p < 0.05).

Conclusion Fluoride/zinc/essential oil-containing mouthrinse can promote enamel fluoride uptake
and microhardness.

(CU Dent J. 2013;36:31-36)