DOI: 10.4103/drj.drj_93_26 ISSN: 1735-3327

Nanostructural evaluation of the protective effects of two fluoride varnishes against enamel erosion

Maede Ghasemi, Ali Ahmadi, Imaneh Asgari
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ABSTRACT

Background:

This study evaluated enamel surface alterations during dental erosion and compared the protective effects of two fluoride varnishes using atomic force microscopy (AFM).

Materials and Methods:

In this in vitro experimental study, 20 caries-free teeth were sectioned, yielding 18 suitable enamel blocks. Baseline surface roughness was measured by AFM, and specimens were randomly assigned to three groups ( n = 6): untreated control, Florish, and FluoroDose. After varnish application, specimens underwent standardized pH cycling consisting of immersion in an Iranian carbonated beverage for 5 min, four times daily, with 1-h remineralization intervals in artificial saliva. Postcycling surface topography was reassessed for average roughness (Ra) and root mean square roughness (Rq). Intergroup comparisons were performed using one-way analysis of variance with Tukey’s honestly significant difference post hoc test, and intragroup changes were assessed using paired t -tests (α = 0.05).

Results:

Baseline Rq ranged from 18.09 to 67.68 nm (mean 40.55 ± 14.5 nm), and Ra ranged from 15.12 to 59.42 nm (mean 32.4 ± 12.6 nm). After erosion, the control group showed a marked increase in Rq, reaching 71.6–277.5 nm (mean 163.0 ± 76.3 nm). Posterosion Rq was significantly lower in the Florish (63.3 ± 9.7 nm) and FluoroDose (60.0 ± 10.6 nm) groups. Both varnishes significantly reduced Ra and Rq compared with the control ( P = 0.003 and P = 0.004, respectively), with no significant difference between varnishes ( P > 0.05).

Conclusion:

Both fluoride varnishes reduced acid-induced enamel roughening in vitro . Florish showed protective efficacy comparable to FluoroDose and may represent a practical domestic alternative, although clinical studies are needed to confirm effectiveness under dynamic oral conditions and establish its long-term preventive value in practice.

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