Application of an MTT-Based Colorimetric Assay to Evaluate SHED Metabolites in Inhibiting Oral Bacteria Growth

Abstract Dental caries and periodontitis are among the most prevalent oral diseases, primarily caused by Streptococcus mutans, Lactobacillus acidophilus, Aggregatibacter actinomycetemcomitans, and Porphyromonas gingivalis. Metabolites from stem cells from human exfoliated deciduous teeth (SHED) expressing human β-defensin 4 exhibit antimicrobial effects. Chitosan-based hydrogels and hydroxyapatite (HA) have also shown antibacterial potential. This study aims to evaluate the antibacterial activity of hydrogels combined with SHED metabolites and HA against oral pathogens using amicroculture tetrazolium technique (MTT)-based colorimetric assay. Hydrogels were combined with SHED metabolites and/or HA, then applied to bacterial cultures. Viability was assessed via MTT assay and absorbance was measured using an enzyme-linked immunosorbent assay reader. Data were analyzed using one-way analysis of variance (ANOVA) and Welch ANOVA (p < 0.05). The group treated with hydrogel + HA + SHED metabolites (K4) showed the lowest bacterial viability across all strains, with statistically significant differences (p < 0.05). Hydrogels combined with SHED metabolites and HA demonstrate promising antibacterial properties and may serve as effective agents in preventing oral infections.