Which material is not compatible with composite resin?

The reason zinc oxide eugenol (ZOE) is not compatible with composite resin lies in the properties of the materials involved. ZOE has a well-documented ability to inhibit the polymerization process of composite resins. This is largely due to the release of eugenol, which is a phenolic compound that can interfere with the setting and hardening of composite materials, leading to compromised bonding and potentially affecting the final aesthetic and structural integrity of the restoration.

In contrast, materials like calcium hydroxide and carboxylate cement are compatible with composite resin. Calcium hydroxide can provide a suitable protective layer that does not adversely affect the bonding process, often used in vital pulp therapy. Carboxylate cements also show good compatibility, working well underneath composite restorations without affecting their performance.

Zinc phosphate cement, while traditionally used in dentistry, is also compatible with composite resins as it does not inhibit their polymerization; instead, it offers good mechanical support and can be used beneath composites safely.