Discussion
toxicity
SMEAR LAYER
This study investigated the effects of different concentrations of NaOCI solution and various final irrigation techniques on the remaining pulp and debris in the root canal. The results showed that the 5.25% of NaOCI solution provided significantly better cleaning in the root canal compared to the 2.5% of NaOCI solution. Furthermore, when NaOCI solution was activated during the final irrigation, laser activation demonstrated a statistically significant difference compared to passive ultrasonic activation and intracanal heating method. Activation of the 2.5% of NaOCI solution using laser, passive ultrasonic, and intracanal heating method did not yield as much cleaning efficiency as the 5.25% of NaOCI solution.Studies suggest that the toxicity of NaOCI increases with its concentration and that it should be used at the lowest effective concentration [When reviewing the existing literature, a consensus emerges that as the concentration of the NaOCI solution increases, its effectiveness also increases. Consequently, 5.25% NaOCI solution is commonly preferred in clinical practice. Additionally, in recent years, irrigation activation methods have been recommended to enhance solution effectiveness. This raises the question, “Is it possible to achieve the effects of high concentrations of NaOCI by activating low concentrations of NaOCI solution? Does this reduce toxicity?'' In this study, 2.5% NaOCI solution was activated using different methods during the final irrigation, and the results were compared with those of 5.25% NaOCI solution. However, the findings indicate that the cleaning efficiency of the high concentration NaOCI solution could not be achieved by activating the low-concentration NaOCI solution using laser, ultrasonic, and intracanal heating methods during the final irrigation. Activation at both concentrations improved solution effectiveness, with Er,Cr:YSGG laser activation demonstrating more effective cleaning in the canal compared to PUI and intracanal heating methods. Notably, the difference between PUI and intracanal heating was significant. Wang et al. [In recent years, researchers have shown interest in increasing the efficiency of NaOCl through heating. Heating the NaOCI solution enhances its flow and reaction rate, resulting in increased antimicrobial activity and tissue dissolution effect[NaOCI is commonly used as an irrigation solution in endodontic treatments due to its antibacterial activity and capacity to dissolve organic tissue. However, it does not have an effect on the inorganic components of the smear layer. Therefore, it is recommended to use proteolotic irrigants such as NaOCI in combination with chelating/calcifying agents like EDTA to remove the smear layer [Various methods are used to evaluate the cleanliness of root canals, including scanning electron microscope (SEM), optical microscope, computed tomography for pre/post instrumentation analysis, and histological analysis. However, none of these methods is considered ideal [