# Cytotoxicity and Antimicrobial Activity of BioAktTM and Phytic Acid: A Laboratory-Based Study
## 4 Discussion  
BioAktTM and phytic acid are considered two novel endodontic solutions that can have wide applications both as chelating agents and irrigant solutions [25,31]. Although NaOCl and EDTA continue to be considered the most effective endodontic combination due to their capacity to destroy necrotic pulp and remove the smear layer, new irrigants which appear to have a broad-spectrum antimicrobial effect with minimal adverse effects on the root canal system have not been identified [32]. For some years, increased attention has been paid to phytic acid, a natural compound, and BioAktTM, a silver ions solution in citric acid as possible solutions for endodontic solutions for dental adhesive [29,33] and endodontic irrigants [34,35]. Compared to NaOCl, BioAktTM and phytic acid might be possible alternatives to reduce the negative consequences related to accidental NaOCl extrusions, such as vascular damage or other irreversible damages [36] and to limit the side effects of NaOCl, such as changes in dentin collagen [37]. From our findings, the antimicrobial capacity of IP6 reported slightly different results between the two experiments. While IP6 did not show statistically significant differences among the three tested concentrations from the disk diffusion test, results showed IP6 was more effective at a concentration of 5% than at 3% or 1% from the 1-h treatment test on _E. faecalis_. Furthermore, regardless of concentration, IP6 gave results similar to the control group. Our results did not confirm previous studies about the antibacterial activity of IP6, and on the contrary, showed biostatic and biocide activities of IP6 against various microbial strains [34]. In contrast to [PERSON] et al., 2021, the increasing concentration of IP6 did not increase its antimicrobial activity, and membrane disruption considered at the base of the bacterial mechanism of action seemed not to act in our study. The relevant difference in antimicrobial activity between NaOCl and IP6 does not allow us to suggest IP6 as a reliable alternative to NaOCl or EDTA. Different findings emerged instead for the antimicrobial activity of BioAktTM, which was more effective than IP6 with antimicrobial capacity similar to that observed with 1.5% NaOCl. This result confirms the optimal antimicrobial activity of BioAktTM that emerged in previous works [21,35]. As [PERSON] et al., 2020, hypothesized, BioAktTM presents nanometric precipitation and silver-containing crystallites, resulting from the high activity and interaction rates of silver ions. In the presence of E. faecalis, silver ions increase their activity to interact with and penetrate the cell membrane of Gram-positive and Gram-negative bacteria, resulting in deoxyribonucleic acid damage and bacterial death [35]. Some doubts have been raised about BioAktTM such as the potential cytotoxicity of silver ions and nanoparticles in endodontics due to a high surface-to-volume ratio and non-specific oxidative injures [38,39]. However, from our findings, all experimented so  
Figure 4: Effect of 1 h treatment. lutions significantly decreased cell viability and ATP production compared to controls, although cell viability appeared less affected than cell activity. Therefore, we hypothesize that the different trends of the two cell viability tests could be explained as a decrease in ATP production in the cell due to the stress caused by each solution, which reduces the cell activity without reducing their viability. Specifically, 1% IP6 was the most significantly biocompatible compound after 4 h, a condition that was not maintained after 24 h where all the concentrations of IP6 reported very similar results. However, cell viability is significantly reduced compared to the control (85% less than control). On the contrary, after 4 h, cell activity is reduced considerably, increasing the phytic acid concentration from 1% to 5%.