Permeability of eroded enamel following application of different fluoride gels and CO2 laser

This study evaluated the combined effect of fluoride compounds and CO(2) laser in controlling the permeability of eroded enamel. Bovine enamel slabs (3 × 2 mm) were cycled twice through an alternating erosion and remineralization regimen. Slabs were immersed in 20 ml of orange juice (pH 3.84) for 5 min under agitation, rinsed with deionized water, and stored in artificial saliva for 4 h to form erosive lesions. Specimens were then divided into four groups (n = 10), which were treated for 1 min with either a control or with one of the following gels: amine fluoride (AmF), titanium tetrafluoride (TiF(4)), or sodium fluoride (NaF). Half of the specimens were irradiated with a CO(2) laser (λ = 10.6 μm; 2.0 W). Specimens were cycled two more times through the aforementioned erosion-remineralization regimen and were subjected to permeability assessment. ANOVA demonstrated a significant interaction between fluoride and laser treatment (p = 0.0152). Tukey's test showed that when fluoride was applied alone, TiF(4) resulted in lower enamel permeability than that observed after application of the placebo gel. Intermediate permeability values were noted after NaF and AmF had been used. A significant reduction in enamel permeability was obtained when fluoride was combined with CO(2) laser treatment, with no difference between fluoride gels. Permeability of eroded enamel may be reduced by combining the application of fluoride gels with CO(2) laser irradiation.