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 Publisher

Summary: Could NaF varnish be better than SDF for children's teeth? Research suggests MI varnish significantly boosts dentin microhardness over SDF. A promising alternative? #Dentistry #ChildHealth

Rafiei S ; Abad AJG ; Paryab M ; Tayebi G ; Younespour S
Source: International Journal of Dentistry Published:2026

Abstract

Background and Objective: 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. Materials and Methods: 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. Results: 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). Conclusions: 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. Copyright © 2026 Sima Rafiei et al. International Journal of Dentistry published by John Wiley & Sons Ltd.