Comparing Enamel Microhardness in Decidous Teeth With Primary Carious Lesions After Applying Three Fluoride Containing Materials in Vitro

For decades, using fluoride has been introduced to prevent the development and progression of primary carious lesions. Increased surface microhardness of primary caries is among the essential factors in preventing lesion progression and cavity formation. The present study aimed to compare the microhardness changes of primary caries treated with 3 products, containing fluoride (varnish, toothpaste, & mouthwash) in dental teeth.

In this study, 45 extracted human deciduous molars were used. Using a diamond-winning disc, enamel blocks with a dimension of 1 x 4 x 4 mm were prepared from the buccal surface of the teeth, i.e., healthy and without structural defects; they were mounted in acrylic self-adhesive. Initial microhardness test (Vicker’s test) with a force of 300 gr and Dwell time for 15 seconds was applied on samples. Next, artificial caries with the standard solution were created in all samples and the microhardness of samples was recorded at this stage. The study samples were randomly divided into 3 groups of 15, treated with fluoride varnish, mouthwash, and toothpaste. Then, the microhardness of samples was re-measured. The mean surface microhardness was compared between the study groups by Independent Samples t-test and Bonferroni test. All analyses were performed using SPSS at the significance level of P<0.05.
Ethical Considerations: This study was approved by the Ethics Committee of the Arak University of Medical Science (Code: IR.ARAKMU.REC.1397.264).

 Increase in surface microhardness of primary caries in fluoride varnish group was statistically significant; in GC MI paste plus toothpaste and Oral B mouthwash was non-significant. The research samples treated by fluoride varnish had a higher surface microhardness, compared to toothpaste and mouthwash.

According to the present research results, fluoride varnish was superior to fluoride mouthwash and toothpaste in improving the microhardness of primary dental caries.