Effect of silver diamine fluoride and nanosilver on salivary bacterial counts in children with early childhood caries: a randomized controlled clinical trial.

Background: Silver diamine fluoride (SDF) is indicated for the management of early childhood caries (ECC). Similarly, nanosilver fluoride (NSF) is effective against caries. However, there are limited comparisons between both agents, especially regarding their antibacterial effect. This randomized controlled clinical trial aimed to compare the effects of SDF and NSF on salivary bacterial counts in children with ECC.

Methods: Fifty 4-6-year-olds presenting with active dentin caries (ICDAS code 5) in primary teeth were randomly allocated to two groups. Streptococcus mutans (S. mutans) and Lactobacilli in unstimulated saliva were cultivated on differential media and counted as colony-forming units. Followed by the application of either 38% SDF or NSF. Saliva samples were recollected after one month. The legal guardians completed a detailed questionnaire assessing their child's dental hygiene habits, dental pain experience, and socioeconomic background. Multivariable binary logistic regression was used to assess the effects of both agents on bacterial counts while accounting for confounders.

Results: The mean age of participants was 4.8 ± 0.8 years, with the majority (96%, N = 48) presenting with severe ECC. There were no statistically significant differences between the two groups regarding age, sex, dmft score, socioeconomic background, dental hygiene habits, or dental experience. After one month, within-group analysis showed a significant reduction in S. mutans only in the NSF group (p = 0.002) and significant decreases in Lactobacilli counts in both SDF and NSF groups (p < 0.05). However, between-group comparisons revealed no significant differences in the reduction of S. mutans (1.4% and 6.0%, respectively, p = 0.192) or Lactobacilli counts (6.0% and 6.0%, respectively, p = 0.754). Regression analyses revealed non-significant odds of reduced bacterial counts after NSF application compared to SDF.

Conclusion: After one application, children with ECC showed significant decrease in salivary bacteria, with no difference between the two agents regarding their antibacterial effect. NSF can serve as a viable option in ECC management in that it provides comparable antibacterial effects to 38% SDF without inducing tooth discoloration. This trial was prospectively registered on the clinicaltrials.gov registry with ID: NCT05221749 on 03/02/2022.