Avaliação da atividade antimicrobiana de bactérias odontopatogênicas por meio da inserção de nióbio em dentifrício fluoretado

Abstract

Dental caries is a multifactorial disease strongly associated with the presence of cariogenic bacteria, especially Streptococcus mutans, Streptococcus mitis, and Streptococcus oralis, which justifies the search for oral care products with potential antimicrobial activity. The incorporation of bioactive metals into dental biomaterials has been widely investigated as a strategy to enhance dental biofilm control, with niobium standing out due to its high chemical stability and potential antimicrobial activity. Nevertheless, studies systematically evaluating the antimicrobial effects of niobium-derived compounds against odontopathogenic bacteria remain scarce, particularly when these compounds are incorporated into fluoridated dentifrices, thereby justifying the present investigation. This study assessed the antimicrobial activity of seven distinct niobium-derived compounds, both in their pure form and when incorporated into a commercial toothpaste formulation, against selected odontopathogenic bacteria. The evaluations included the determination of the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) using the broth microdilution assay, in addition to complementary analysis by the agar diffusion method. A selective inhibitory and bactericidal effect of the niobium compounds was observed against Streptococcus mitis and Streptococcus oralis, whereas Streptococcus mutans did not exhibit susceptibility at the tested concentrations. In the agar diffusion assay, the incorporation of 10% niobium pentoxide and niobium nitride into the commercial dentifrice resulted in increased inhibition zones against S. mitis compared with the dentifrice alone. However, these compounds did not enhance antimicrobial activity against S. mutans or S. oralis. These findings suggest species-dependent antimicrobial activity, indicating selective potential and the need for further investigations for clinical application.