Why can't ZOE be used under resin materials?

Zinc oxide eugenol (ZOE) cannot be used under resin materials primarily because of the presence of eugenol, which has a tendency to inhibit the polymerization process of resins. When eugenol comes into contact with the components of resin-based materials, it can disrupt the curing reaction that is essential for the resin to harden and achieve its mechanical properties. This inhibition occurs because eugenol interferes with the chemical reactions that take place when a resin is being cured, leading to incomplete polymerization and potentially compromised strength and durability of the restoration.

Understanding this interaction is critical in dental practice, as using ZOE in situations where resin materials are to be placed can result in significant clinical failures. The other choices, although they may have some basis in clinical considerations, do not directly pinpoint the core issue of polymerization interference caused by eugenol. Thus, the primary concern is the effect of eugenol on the curing process of resin materials.