NOTCH2 and periapical periodontitis: Notably, Notch1 signaling promotes alveolar bone repair, whereas Notch2 signaling inhibits it.177,178 Notch2 upregulation coincides with increased IL-1β and IL-6 levels, creating an osteoclast-favorable environment.168 In periapical periodontitis lesions where RANKL expression exceeds OPG, Notch2, Jagged1, Hey1, and TNF-α are overexpressed and strongly correlated, collectively driving extensive alveolar bone resorption.169