## 4 Discussion  
Based on the results of the current study, the null hypothesis, which stated that all the tested toothpastes would exhibit the same antimicrobial properties, was rejected. More specifically, SAMPLE A (with 0.1% Biosecur Organic Oral Care) was more effective against two of the three microorganisms studied (Streptococcus mutans and Prevotella intermedia) compared to the positive control (synthetic toothpaste). For the third strain (Candida albicans), the results were comparable. It was clearly more effective than the other two toothpastes, SAMPLE B (with 0.1% \(w/w\) Microsilver BG) and SAMPLE C (with 0.5% \(w/w\) Cranberry LG). On the other hand, SAMPLE B exhibited nearly the same performance as the positive control against all the microorganisms and performed better than SAMPLE C, while SAMPLE C exhibited slightly lower activity against all the microorganisms compared to the positive control. It was therefore concluded that the flavonoids found in the mandarin fruit, the bitter orange fruit, and the sweet orange peel (Biosecur Organic Oral Care) were more effective against the three microorganisms studied compared to silver and the proanthocyanidins contained in cranberry extract. These differences in the antimicrobial properties may be attributed to the concentration of the active agents and the different mechanisms of antimicrobial action that they exhibit. Based on the above, the composition selected for the development of SAMPLE A (0.1% Biosecur Organic Oral Care) could serve as a viable proposal, in combination with the other natural ingredients, for the development of a natural toothpaste. Figure 4: Representative samples of Petri dishes of all the experimental groups that indicate the inhibition zones (green line—IZ) that were formed in Prevotella intermedia cultivations. (**a**): 0.1% Biosecur organic oral care-containing, (**b**): 0.1% Microsilver BG-containing toothpaste, (**c**): 0.5% Cranberry LG-containing toothpaste, (**d**): baseline toothpaste (control\(-\)), (**e**): synthetic toothpaste (control+), (**f**): water (negative test). Flavonoids, which were included in the SAMPLE A, are a diverse group of plant-derived polyphenolic compounds and exhibit remarkable antimicrobial properties that make them valuable in dental products. These compounds target oral pathogens, such as Streptococcus mutans, Candida albicans, and Prevotella intermedia, which are associated with dental caries, periodontal diseases, and oral infections [36; 37]. Flavonoids disrupt bacterial cell membranes, inhibit enzymes critical for microbial metabolism, and prevent biofilm formation, thereby reducing plaque accumulation and the risk of oral diseases [38]. Additionally, their antioxidant and anti-inflammatory properties help protect gum tissues from oxidative damage and inflammation caused by bacterial toxins [39]. By incorporating flavonoids from sources, such as citrus fruits, tea, and herbs, dental products, like toothpastes and mouthwashes, offer a natural, effective means to enhance oral hygiene and health [40]. Silver, which was included in SAMPLE B, has long been recognized for its potent antimicrobial properties, making it a valuable ingredient in dental products [41]. In its nanoparticle form, silver releases ions that disrupt microbial cell membranes, inhibit vital enzymatic functions, and interfere with DNA replication, effectively neutralizing a wide range of bacteria, fungi, and viruses commonly found in the oral cavity [42]. This broad-spectrum antimicrobial activity helps reduce dental plaque formation, combat periodontal pathogens, and prevent oral infections, such as gingivitis and periodontitis [43]. Additionally, silver exhibits a prolonged antimicrobial effect due to its sustained ion release, enhancing its efficacy in dental products, like toothpastes, mouthwashes, and dental coatings. Its biocompatibility and effectiveness at low concentrations further underscore its suitability for use in maintaining oral health [44].