Clinical, Microbiological, and Microcomputed Tomography Evaluation of Silver Diamine Fluoride in Controlling Root Carious Lesions: An in Vivo Study.

Background: Silver diamine fluoride (SDF) application without removing necrotic tissue is an applicable non-invasive measure to primary care practice and may reduce the burden of untreated root caries. This study aims to examine clinical feature change, root caries-related bacteria, and silver penetration of SDF in arresting root caries.

Material and methods: Ten study participants with 16 root carious teeth were included in this study. The clinical characteristics of root caries lesions (plaque deposit, color, hardness, and sensitivity symptom) were recorded. Then root caries samples were collected using a spoon excavator before and 2 weeks after treated with 38% SDF. The amounts of Streptococcus mutans (S.mutans), Actinomyces naeslundii (A. naeslundii), and Lactobacillus casei (L. casei) were determined using real-time PCR. Any tooth sample scheduled for extraction was further analyzed using micro-CT, stereoscopic microscope, and FE-SEM/ EDX to determine the silver penetration.

Results: Most treated samples were darker in color, predominantly turning black (n =15, 93.8%), had increased surface hardness (n =11, 68.8%), were non-sensitive teeth (n=14, 87.5%), and were negative to air blowing (n =12, 75%). Only S.mutans had a significantly lower number of bacteria after 2 weeks (p-value = 0.041). The micro-CT analysis revealed that the silver increased the root carious lesion's density in proportion to its depth. According to a stereoscopic microscope study, silver penetration caused dark bands, appearing along the dentinal tubule toward the dental pulp. An FE-SEM analysis showed that silver was found to be densely deposited on the surface of the lesions and penetrated through the dentinal tubule into the dental pulp direction. EDX mapping confirmed that the increased density was related to silver.

Conclusions: Based on clinical and microbiological profiles, this investigation indicated that SDF is beneficial for controlling root caries, particularly S.mutans reduction. Silver can also penetrate deep into the lesion. Key words:Microbiology, Root caries, Silver diamine fluoride, Silver ion, Streptococcus mutans, Actinomyces naeslundii, Lactobacillus casei.