# Comparison of the Microhardness of Primary Dentin With Artificially Induced Caries Following the Application of Sodium Fluoride Varnish With the Intensive Technique Versus Fluoride Therapy With Silver Diamine Fluoride

## TL;DR

This study compares how two fluoride treatments affect the hardness of tooth dentin in children with early caries, finding that a specific fluoride varnish protocol is more effective than silver diamine fluoride.

## Contribution

The study introduces an intensive application protocol of sodium fluoride varnish with CPP-ACP as a potentially superior alternative to silver diamine fluoride for managing early childhood caries.

## Key findings

- The microhardness of dentin significantly increased in the NaF varnish groups after 45 days.
- MI varnish with CPP-ACP showed a greater increase in microhardness compared to other treatments.
- The microhardness pattern changed significantly differently among the three treatment groups.

## Abstract

Black discoloration is a major challenge encountered when using silver diamine fluoride (SDF) to manage early childhood caries (ECC). This study aimed to assess the carious primary dentin microhardness following the application of sodium fluoride (NaF) varnish with the intensive technique versus fluoride therapy with SDF.

In this in vitro study, 45 extracted relatively sound primary molars were randomly assigned to three groups: Group 1: Application of 30% SDF, Group 2: Application of Aria Dent varnish (5% NaF) three times within 10 days, and Group 3: Application of MI varnish (5% NaF + casein–phosphopeptide amorphous calcium phosphate [CPP‐ACP]) three times within 10 days. After sectioning and dentin surface preparation, dentin microhardness was measured at four different time points: baseline, after demineralization, and 24 h and 45 days after the application of the respective fluoride product. The teeth were under pH‐cycling throughout the entire study period. The microhardness values were compared among the groups, and at different time points using the generalized estimating equations (GEEs) model.

The mean microhardness at 24 h after treatment was not significantly different from that after demineralization in any group (p > 0.05). The mean microhardness significantly decreased in the 30% SDF group and significantly increased in the two NaF varnish groups at 45 days compared to 24 h (p  < 0.05). The pattern of change in microhardness was significantly different among the three groups (p  < 0.0001). MI varnish increased the microhardness significantly more than the other products within the 45‐day study period (p  < 0.05).

The intensive protocol of NaF varnish application three times within 10 days, especially MI varnish that contains CPP‐ACP, may enhance the microhardness significantly more than SDF in the first month of use. This protocol may be able to serve as an efficient alternative to SDF.