## 4 Discussion  
Recently, a new formula of biocercamic (BC-HiFlow) sealer was manufactured to resist the high temperature subjected during warm vertical compaction technique. It is important for clinician to understand the behaviour and performance of root canal sealer under clinical situation. The sealer solubility has an impact on the longevity of endodontic treatment. Figure 3: SEM/EDX analysis of the three sealers before (**A**–**F**) and after 28 days (**G**–**O**) immersion in water. (*****) is the significant greatest value while (\(\dagger\)) is the significant lowest value at \(p\) < 0.001. (\(\
eq\)) indicates there is no significant difference between sealers with the same symbol at \(p\) > 0.05. It could induce sealer degradation; compromising the apical seal, and enhance bacterial leakage [5]. The current study investigated the impact of water solubility on the chemical properties of the first (BC-EndoSquence) versus the recent (BC-HiFlow) generation of bioceramic sealers. Although both sealers have nearly similar composition [10], their chemical behaviour and surface morphology (particularly after water immersion) have been currently reported to be different. Hence, the null hypothesis was rejected. Both BC-sealers displayed solubility% with the significant greater values obtained by BC-EndoSquence greater than acceptable level of ISO [18], within 21 days (Figure 1A). The high solubility was previously reported by both BC-sealers in other studies which was either in accordance with acceptable limit (3% mass fraction) [33] or more exaggerated than the recommended with ISO [4; 6; 8; 12; 34]. The present result recorded the solubility values within an acceptable limit within the first 14 or 21 days for BC-Endosequence or BC-HiFlow, respectively (Figure 1A). This discrepancy of current versus previous findings may be due to the solubility test was performed after one month until maximum material setting. Conversely, Adseal underwent to gain weight that gradually increased then declined after 21 days. This finding is in accordance with previous study [35]. Adseal resin-based sealer was used as a control sealer due to its availability. It is also composed of calcium phosphate comparable to bioceramic based sealers. Moreover, several studies reported good solubility property similar to other resin based sealer such as AH-plus [36]. The sealer solubility seems to be influenced by multiple factors, setting time and composition. In turn, it may induce greater release of elements and pH changes. According to [PERSON], slow initial setting without further prolonged final setting and alkaline pH are essential properties required for an ideal root canal sealer [3; 37]. BC-EndoSquence displayed the significant prolonged initial setting time and failed to complete set until 3 months (Table 1). However, BC-HiFlow recorded 4.12 and 37 hrs for initial and final setting time, respectively. The prolonged setting time of BC-Endosequence was previously reported, where it was exceeding one month [38]. It was suggested that the BC-EndoSquence, as a hydraulic sealer, did not set in >95% humid incubator [35] and it set in a moist environment similar to root canal system that contains fluid inside dental tubules [4]. There were few studies related to BC-HiFlow. The current finding was nearly similar to two studies which recorded 4-6 and 31-33 hrs for initial and final setting, respectively [16; 39]. In addition, they showed no significant difference between setting time of BC-EndoSquence and BC-HiFlow after heat application [16; 39]. Thus, heat seems to accelerate the hydration reaction [18; 39]. Reciprocal reaction was noted between solubility, released by-products, and pH. Sealer with high alkaline pH and Ca\({}^{2+}\) release consider as favourable root canal sealers to enhance antibacterial and osteogenic activity [7; 13; 33; 40; 41; 42].