Which material is most commonly used to stimulate dentinal bridge formation in vital pulp therapy (direct pulp capping)?

Calcium hydroxide has traditionally been the material of choice for direct pulp capping to stimulate reparative dentin (dentinal bridge) formation. Its high pH (approximately 12.5) creates a superficial zone of coagulation necrosis at the pulp-material interface, which stimulates underlying pulp cells (odontoblasts and undifferentiated mesenchymal cells) to differentiate and deposit a mineralized dentinal bridge. While mineral trioxide aggregate (MTA) and bioceramic materials (like Biodentine) have shown superior long-term outcomes in recent studies and are gaining acceptance as first-line agents for vital pulp therapy, calcium hydroxide remains the classic textbook answer for dentinal bridge formation. For examination purposes, calcium hydroxide is the expected answer.