Antibiofilm Property of Silver Diamine Fluoride Against Elected Periodontal Pathogens: An In Vitro Study

OBJECTIVE: This in vitro study aimed to evaluate the antibiofilm effects of silver diamine fluoride (SDF) against key periodontal pathogens. METHODS: Single-species biofilms of the periodontal pathogens Porphyromonas gingivalis, Fusobacterium nucleatum, and Aggregatibacter actinomycetemcomitans, as well as their consortium biofilm, were established on glass coverslips by anaerobic incubation for 72 hours. Mature biofilms were subsequently treated with 38% SDF solution for three minutes. Biofilm viability was assessed using confocal laser scanning microscopy (CLSM). Biofilm morphology and ultrastructure were examined via scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. 0.2% chlorhexidine gluconate (CHX) served as a positive control, while phosphate-buffered saline (PBS) served as a negative control. RESULTS: CLSM showed that the percentage of viable cells in biofilms treated with SDF, CHX and PBS was 9.67% ± 1.53%, 31.33% ± 4.73%, and 89% ± 3.61% for Porphyromonas gingivalis; 6.33% ± 0.58%, 33.33% ± 4.73%, and 75.67% ± 8.74% for Fusobacterium nucleatum; 6.67% ± 1.53%, 29.33% ± 4.04% and 83.33% ± 7.37% for Aggregatibacter actinomycetemcomitans, and 8% ± 1%, 31.33% ± 2.52%, and 74.67% ± 6.66% for the multi-species biofilm (p < .001; SDF<CHX<PBS). SEM images confirmed that SDF markedly disrupted biofilm morphology, leading to greater reductions in biofilm density than CHX. TEM analysis further demonstrated that SDF induced severe ultrastructural damage, including abnormal membrane curvature and disruption of cytoplasmic and cell wall integrity. CONCLUSION: 38% SDF shows stronger antibiofilm activity than 0.2% CHX against key periodontal pathogens, markedly reducing biofilm viability and disrupting structural integrity. CLINICAL SIGNIFICANCE: These in vitro findings support further evaluation of SDF as an adjunct to conventional periodontal therapy, particularly in patients at high risk of biofilm-mediated periodontal disease.