Anti-Cariogenic Effect of Trans-Cinnamaldehyde in an In Vitro Mouse Jaw Explant Model.

Background

Dental caries, primarily caused by Streptococcus mutans (S. mutans), is a prevalent condition with significant global impact. Trans-cinnamaldehyde (TC), a phytochemical derived from the cinnamon plant, has shown promising antibacterial and antibiofilm activity against S. mutans. This study aimed to evaluate the anti-cariogenic effects of TC on S. mutans using an innovative mouse jaw explant model.

Methods

TC was diluted in an organic solvent across various concentrations. Initially, cytotoxicity assays were performed at all tested TC concentrations. Sub-minimum bactericidal concentrations were then used to examine the distribution and morphology of S. mutans biofilms. Hemi-mandibles were dissected from euthanized, healthy, seven-week-old female mice to study the impact of TC on the cariogenic activity of S. mutans using stereoscopic analysis. Finally, pH changes during exposure to cariogenic conditions and post-treatment bacterial viability were measured.

Results

In vitro data demonstrate that TC doses of ≤625 µg/mL were non-cytotoxic. Treatment groups exposed to TC exhibited altered bacterial morphology, including abnormal and incomplete cell division. In the mouse jaw explant model, TC doses of ≥625 µg/mL showed anti-cariogenic effects, evidenced by the absence of visible carious lesions. Additionally, pH changes and post-treatment viable bacterial counts corresponded with the observed anti-cariogenic activity. TC doses ≤625 µg/mL led to a pH drop over time and the presence of bacterial colonies.

Conclusions

TC exhibits significant anti-cariogenic activity against S. mutans in the mouse model. Our findings suggest that 625 µg/mL is the lowest non-toxic concentration of TC that effectively inhibits cariogenic activity.