Alkali soluble fluoride deposits on bovine dental enamel after treatment with a mouthwash containing fluoride and chlorhexidine

Aim: The aim of this in vitro study was to determine whether the addition of chlorhexidine (CHX) to a mouthwash containing fluoride (F) diminishes the concentration of soluble F and its reactivity with  bovine dental enamel. Materials and Methods: First, the concentration of F found in mouthwashs was determined by an ion-specific electrode. To test their reactivity, 30 slabs of bovine dental enamel (5 x 5mm) were distributed into three groups (n = 10), according to the treatment applied, for 30 seconds: control group (distilled deionized water); NaF group (0.05% sodium fluoride); NaF + CHX group (Noplak Max®: 0.05% sodium fluoride + 0.12% chlorhexidine digluconate). After, the slabs were washed with distilled deionized water and individually immersed in artificial saliva for 30 minutes. They were dried and then individually immersed in 0.5 mL of 1M KOH for 24 hours, under agitation. After buffering the samples with HCI containing TISAB II, the concentration of F present in the KOH solutions was determined be means of an ion-specific electrode. Results: No significant difference in the concentration of soluble F in the studied mouthwashs (NaF and NaF+CHX; Student’s t-test, p > 0.05) could be observed. Furthermore, no difference could be identified among the alkali soluble fluoride deposits from the NaF and NaF+CHX groups, and both groups presented higher deposit levels than did the control group (Kruskal-Wallis and Dunn´s method, p < 0.05). Conclusion: The addition of CHX to a mouthwash containing F did not decrease its soluble F concentration, nor its reactivity to bovine dental enamel. Uniterms: Fluorides. Topical. Chlorhexidine. Mouthwash.