Probiotics are live bacteria that provide proven benefit, being an important axis in the public health of people when consumed. This work determined the inhibitory effect of probiotic strains at different concentrations on some dental biofilm-forming bacteria, such as Porphyromonas gingivalis (ATCC 33277) and Actinomyces viscosus (ATCC 15987) in 24 h. This is a study at the application level, experimental, longitudinal design and with prospective measurements. Native Lactobacillus plantarum was obtained from corn ferment through the laboratory maceration procedure. Probiotic Lactobacillus plantarum was subjected to the t statistical test on dental biofilm-forming bacteria and to the Tukey contrast statistical test to determine the inhibitory effect of the halos at concentrations from the purest concentration which is 100% to 25% of the probiotic Lactobacillus plantarum on plaque-forming bacteria. The 100% concentration of Lactobacillus plantarum demonstrated the greatest inhibitory effect against Porphyromonas gingivalis, with an inhibition zone of 14.89 mm., followed by a 75% concentration of the probiotic Lactobacillus plantarum against the bacteria Actinomyces viscosus. The lowest inhibitory effect was found in a 25% concentration of the probiotic Lactobacillus plantarum against the bacteria Porphyromonas gingivalis, and the highest antimicrobial effect was recorded by the 100% Lactobacillus plantarum ferment at 24 h against Actinomyces viscosus with a halo of 15.88 mm.