## 4 Discussion
[11], who concluded that apical plugs with a thickness of 4 mm exhibited superior marginal adaptation and sealing ability. Additionally, [PERSON] et al. [43] highlighted that a greater depth of plug material could lead to increased expansion, subsequently reducing gaps. The lack of statistically significant differences between the two materials presented in our study, in the cervical region, is aligned with findings from some studies, which have concluded that there are no statistically significant differences when White ProRoot MTA(r) is compared with various hydraulic calcium silicate cements, despite the different methodologies used [44; 45; 46; 47]. The significant differences observed in this study regarding the marginal adaptation of the two materials may be associated with their physical and chemical properties, including volumetric changes and solubility, as well as their presentation form and application. These factors play a role in how the material adapts to the root canal walls and seals the apical region, influencing the overall success of the root canal treatment. The superior results associated with White ProRoot MTA(r) in the apical region may be attributed to its dimensional stability, volumetric expansion capacity, easy application and low compressive force during setting [24; 48; 49; 50]. In the study by [PERSON] et al. [51], TotalFil(r) BC RRM Fast Set Putty(tm) demonstrated a higher compressive strength during setting, notably surpassing that of White ProRoot MTA(r). This higher compressive strength could potentially be a contributing factor to the greater lack of marginal adaptation observed in TotalFil(r) BC RRM Fast Set Putty(tm). Another plausible explanation for the lower adaptation of TotalFil(r) BC RRM Fast Set Putty(tm) compared to White ProRoot MTA(r) in this study is linked to its working time, which ideally needs to be short, and to the consistency of the material, which may be relatively challenging to insert and handle in the root canal [8]. Additionally, TotalFil(r) BC RRM Fast Set Putty(tm) is recognized for its low porosity [52], which may contribute to its high compressibility [51]. The graphical boxplot representation clearly shows the superior performance of White ProRoot MTA(r) in the apical section despite its standard deviation. The boxplot graph allows the identification of the few outliers that influenced the standard deviation. These outliers appear to be linked to the material's sensitivity to the application technique or sensitivity to the humidity of the canal system or may be associated with the microscopy protocol. In accordance with the American National Standards Institute (ANSI)/American Dental Association (ADA) Specification 57, the solubility of cements should not exceed 3% of their mass. Exceeding this limit may result in the development of gaps between the material and the canal walls, leading to diminished marginal adaptation [19]. Therefore, low solubility is a critical property for endodontic cements to prevent their dissolution into the periapical tissues [53]. Numerous studies have reported that TotalFil(r) BC RRM Fast Set Putty(tm) exhibits a solubility above 3% [54; 55; 56]. In a study by [PERSON] et al. [56], the solubility of TotalFill(r) BC RRM Fast Set Putty(tm) was assessed in both distilled water and phosphate-buffered saline (PBS), a saline solution whose concentration simulates that of the human body. These authors concluded that TotalFill(r) BC RRM Fast Set Putty(tm) had a significantly greater solubility and volumetric loss than AH Plus. Despite the solubility of this hydraulic calcium silicate cement being relatively low, it remains above the minimum recommended by International Organization for Standardization (ISO) ISO 6876 [27; 56]. In contrast, White ProRoot MTA(r) has demonstrated lower solubility values, even in biological fluids [57; 50; 58].