## 4 Discussion  
VRFs in ETT are inconvenient for both the patient and the dentist. VRFs typically develop slowly and go undetected by patients until clinical signs and symptoms arise [28] at which point root resection and tooth extraction are usually required [29]. In order to enhance the fracture resistance of ETT, clinicians have long worked to strengthen the remaining tooth structure [30]. In this situation, it would be advantageous to employ a root canal filling material or sealer that also reinforces the root against fracture [31]. The current study investigated and compared the fracture resistance of AH Plus and BioRoot RCS following thermomechanical ageing. The null hypothesis was rejected since all sealers demonstrated significant changes after different time periods of the thermomechanical cycling. The purpose of the aging techniques is to simulate the challenges that chewing, clenching, and/or bruxing habits place on teeth and restorative materials in vivo by applying repeated and continuous mechanical pressures [32]. The aging method's objective is not to immediately cause fractures, but rather to demonstrate that these may occur over time as the surrounding teeth and restorative material become more brittle. The spread of cracks could ultimately combine to raise the risk of chipping or catastrophic fractures [33]. By creating expansion and contraction stresses as a result of alternate immersions in liquid media at low and high temperatures, thermal cycling leads to stresses in the obturation material, the root canal wall, and the bonded interface [34]. The repeated temperature \begin{table}
\begin{tabular}{c c c c} \hline
**Sealer** & **Control Group** & **MC G \(\times\) 105)** & **MC (6 \(\times\) 105)** & _p-Value_ \\ \hline AH Plus & 57.605 \(\pm\) 15.207 A,a & 98.41 \(\pm\) 19.335 A,b & 53.696 \(\pm\) 24.082 A,a & 0.000 \\ BioRoot RCS & 1161.671 \(\pm\) 214.948 B,a & 730.362 \(\pm\) 133.296 B,b & 672.919 \(\pm\) 131.109 B,b & 0.000 \\ \(T\)-test _p_-value & 0.000 & 0.000 & 0.000 & 0.000 \\ \hline \end{tabular}
\end{table} 
Table 2: Mean and SD of force required for fracture of tooth of tested sealers at two different thermomechanical time periods. Within same row, different superscript lowercase letters mean statistical difference between groups (\(p\) < 0.05). Within same column, different superscript uppercase letters mean statistical difference between groups (\(p\) < 0.05). Figure 5: Mean force strength (N) of sealers at different time intervals. variations and chewing loads may impact the mechanical performance of obturation. Root canal sealers may experience accelerated mechanical deterioration and fatigue if mechanical and thermal cycling are used simultaneously (thermomechanical cycling) [35]. For a better understanding of mechanical material behavior, an in vitro methodology that can replicate some in vivo challenges must be developed. After repeated loading, mechanical cycling (MC), a fatigue test that can replicate masticatory activity, may cause structural fractures, which can be explained as the result of minute fissures spreading from concentrated areas of strain [36]. MC provides an excellent tool for predicting the clinical efficacy of various materials and restoration procedures [37]. The chewing simulator in a computer-controlled mastication simulation is the most widely used fatigue device. It can mimic the masticatory pressures and the environment that dental restorations are exposed to while in use [36]. The BioRoot RCS manufacturer instructs using a single cone or cold lateral condensation (LC) methods for obturation [38]. Because warm vertical compaction is not recommended for the bioceramic sealers tested in this study, it would affect the adhesion properties of these materials, which would have an impact on the outcomes [39]. According to [PERSON] et al. [40], cold lateral compaction of gutta-percha produced noticeably more voids, especially coronally, than a single gutta-percha cone obturation.