Antimicrobial Effect of Arrabidaea chica Polyphenolic Extract Used as Dentin Pre-treatment against Cariogenic Microbiota

Aims: This study tested the antimicrobial effect of Arrabidaea chica (Ac) polyphenolic extract in different concentrations incorporated into an aqueous solution or into a primer of an adhesive system used for cavities pre-treatment against Streptococcus mutans (Sm) and Lactobacillus casei (Lc).

Study Design: In vitro experimental study design to evaluate the minimum inhibitory concentration (MIC) of different solutions containing Ac against Sm and Lc.

Methodology: Aqueous solution and primer (from a self-etching adhesive system - Clearfil SE Bond/Kuraray) were prepared containing Ac extract in six different concentrations: 0.0% (null); 0.25%; 0.5%; 1.0%; 1.5%; 2.0%; 2.5%. To determine the MIC, tubes with the inoculates of Sm and Lc were added with the solutions described above. Serial dilutions were inoculated in plates with culture medium (n=3). The colony forming unit count (CFU/mL) was carried out after 48 hours. Negative controls (aqueous or primer solutions without Ac incorporation) were used in both tests.

Results: Regression model showed that all Ac concentrations inhibited Sm growth (p>0.05) in aqueous solution. Negligible or no Sm growth was observed in the presence of primer in Ac concentrations above 0.25% (p<0.05). Negligible or no Lc growth was found in aqueous solution for all Ac concentrations, and in the presence of primer in Ac concentrations above 1% (p>0.05). All concentrations of Ac tested here maintained the acidic characteristics of the solutions.

Conclusion: Arrabidaea chica extract into an aqueous solution shows antimicrobial effect against Sm and Lc in all concentrations tested. When incorporated into the primer, the antimicrobial activity is observed in concentrations above 1%.