## 5 Discussion  
It is widely accepted that the main reason for root canal treatment failure is the presence of residual microorganisms in the root canal. Therefore, one of the most important challenges for dentists is the proper disinfection of the dental canals and the removal of pathogens [2; 37]. This in vitro study compared the efficacy of three laser modalities, including diode laser, high-frequency diode laser, and SWEEPS, on _E. faecalis_ infected root canal. Due to its resilience in comparison to other species and resistance to alkaline environments, _E. faecalis_ might be a problem germ in persistent root canal infections. According to a study, the susceptibility to disinfection of _E. faecalis_ in the dual-species biofilms did not change, suggesting that the shift in biofilm composition toward more _E. faecalis_ indicates a shift toward more resilient species that may ultimately become more difficult to treat [38]. We have employed a root canal biofilm model, which can closely simulate in vivo situations in terms of morphology, to compare the effectiveness of biofilm removal procedures. Removing the root canal biofilm is still challenging [39]. The biofilm removal techniques still require a more reliable treatment protocol [3]. In an earlier study, the authors found that SWEEPS is an effective intervention in this regard. Moreover, the SWEEPS technique associated with a light-emitting diode (LED) can cause a more significant response on the root canal biofilm model [40]. In this study, SWEEPS exhibited the capacity to remove biofilm during root canal irrigation, which indicated that SWEEPS has the potential to affect biofilm removal from the root canal. The results of our bacterial quantification analysis demonstrated that laser irradiation is effective in reducing bacterial content. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Experiments** & \multicolumn{2}{c}{**Log\({}_{10}\) CFU/mL Reduction**} & \(p\)**Value** \\ \hline MB & vs. Control & \(-0.02\) & \(1.00\) \\ HP & \(-0.61\) & \(<\)0.001 \\ MB + 660 nm DL & \(-0.73\) & \(<\)0.001 \\ HP + 980 nm DL & \(-0.91\) & \(<\)0.001 \\ MB + SWEEPS & \(-0.77\) & \(<\)0.001 \\ HP + SWEEPS & \(-1.05\) & \(<\)0.001 \\ MB + 660 nm DL + SWEEPS & \(-1.58\) & \(<\)0.001 \\ HP + 980 nm DL + SWEEPS & \(-5.97\) & \(<\)0.001 \\ NaOCl & \(-5.97\) & \(<\)0.001 \\ MB + 660 nm DL & vs. MB & \(-0.71\) & \(<\)0.001 \\ MB + SWEEPS & \(-0.75\) & \(<\)0.001 \\ MB + 660 nm DL + SWEEPS & \(-1.56\) & \(<\)0.001 \\ NaOCl & \(-5.95\) & \(<\)0.001 \\ MB + SWEEPS & vs. MB + 660 nm DL & \(-0.04\) & \(0.982\) \\ MB + 660 nm DL + SWEEPS & \(-0.85\) & \(<\)0.001 \\ NaOCl & \(-5.24\) & \(<\)0.001 \\ MB + 660 nm DL + SWEEPS & vs. MB + SWEEPS & \(-0.81\) & \(<\)0.001 \\ NaCl & \(-5.20\) & \(<\)0.001 \\ HP + 980 nm DL & vs. HP & \(-0.30\) & \(0.014\) \\ HP + SWEEPS & \(-0.44\) & \(0.002\) \\ HP + 980 nm DL + SWEEPS & \(-5.36\) & \(<\)0.001 \\ NaOCl & \(-5.36\) & \(<\)0.001 \\ HP + SWEEPS & vs. HP + 980 nm DL & \(-0.14\) & \(0.982\) \\ HP + 980 nm DL + SWEEPS & \(-5.06\) & \(<\)0.001 \\ NaOCl & \(-5.06\) & \(<\)0.001 \\ HP + 980 nm DL + SWEEPS & \(-4.92\) & \(<\)0.001 \\ NaOCl & vs. HP + SWEEPS & \(-4.92\) & \(<\)0.001 \\ NaOCl & \(-5.06\) & \(<\)0.001 \\ \hline \hline \end{tabular} Abbreviations: MB: methylene blue, HP: hydrogen peroxide, nm: nanometer, DL: diode laser, SWEEPS: shock wave enhanced emission photoacoustic streaming, NaOCl: 5.25% sodium hypochlorite.  
\end{table} 
Table 1: Comparative data (Log\({}_{10}\) CFU/mL reduction) of root canal biofilm model following each treatment. In this study, MB and HP, along with a diode laser or SWEEPS, were employed for targeting _E. faecalis_ in the root canals. Our findings are consistent with [PERSON], et al., [41], whose study reported less than 1 log\({}_{10}\) CFU/mL reduction of six-species oral biofilm on a bovine-enamel disc model after their treatment with MB plus 665 nm diode laser. Similarly, 5% NaCl eliminated all strains.