## 4 Discussion  
The bacterial microleakage of root canals can be minimized or avoided through effective and complete adaptation between root canal filling materials and root canal walls [11], particularly endodontic cements, which should maximize marginal adaptation to the root canal walls. This is crucial to seal irregularities that could potentially allow bacterial infiltration into the root canal system, ultimately preventing endodontic failure [31]. The correlation between the marginal adaptation and sealing ability of a material has been a topic of debate. Some studies, such as [PERSON] et al. [32] and [PERSON] et al. [33], have found no direct association between these two properties. On the other hand, several studies establish a clear correlation between these variables [34; 35; 36; 37; 38; 39]. For instance, the study by [PERSON] et al. [38] investigated the correlation between marginal adaptation and the sealing ability of endodontic materials [40]. The existing literature reflects a diversity of findings and perspectives. This study aimed to explore differences in adaptation between the apical and cervical regions of the plug. The results indicated that in both the GMTA group (\(p\) = 0.173) and the GTBC group (\(p\) = 0.311), there were no statistically significant differences between the two regions. The marginal adaptation remained relatively consistent across the entire 5 mm length of the plugs, highlighting homogeneity and uniformity in the distribution of the two materials within the sample plugs. In terms of the comparison of marginal adaptation between White ProRoot MTA(r) and TotalFill(r) BC RRM Fast Set Putty(tm), the present study revealed statistically significant differences (\(p\) = 0.029) in the apical region. Specifically, White ProRoot MTA(r) exhibited a lower mean lack of marginal adaptation (1.32 \(\pm\) 4.37) compared to TotalFill(r) BC RRM Fast Set Putty(tm) (7.92 \(\pm\) 11.94). As for the cervical region, the differences in the lack of marginal adaptation between White ProRoot MTA(r) (7.51 \(\pm\) 14.47) and TotalFill(r) BC RRM Fast  
Figure 4: Graphical representation of the mean percentages of marginal adaptation discrepancy between the White ProRoot MTA and TotalFill® BC RRM Fast Set PuttyTM groups in the cervical zone and between the White ProRoot MTA and TotalFill® BC RRM Fast Set PuttyTM groups in the apical zone. Boxplots represent the median, interquartile range and level of statistical significance between groups: ns—not significant; *\(\rightarrow\)\(p\) < 0.05; GMTA—White ProRoot MTA® group; GTBC—TotalFill® BC RRM Fast Set PuttyTM group. Set Putty(tm (7.34 \(\pm\) 14.68) were minimal and no statistically significant differences were observed (\(p\) = 0.774). It is worth noting that the results obtained in this study may diverge from those of research studies, potentially influenced by variations in sample processing, preparation and evaluation methodologies. The null hypothesis was accepted for the cervical section, with no statistically significant differences in marginal adaptation between the two cements. However, it was rejected for the apical section, revealing that White ProRoot MTA(r) exhibited superior marginal adaptation with statistically significant differences. Designing an in vitro model of an open apex poses challenges, due to the complexity of simulating the anatomical relationship between the tooth and periapical tissues [41]. In this study, a methodology was employed which uses floral sponges to simulate the periapical tissue environment, with a retrograde instrumentation technique described in a previous study [9; 42]. The preparation of the root segments was standardized to ensure uniform dimensions across all teeth. It effectively replicates the characteristics of immature teeth with open apices, providing a controlled and comparable foundation for the evaluation of marginal adaptation with the two calcium silicate-based cements tested. Apical plugs of approximately 5 mm were prepared, guided by findings from [PERSON] et al.