- Restorative materials used in dentistry exhibit different mechanical behaviors when subjected to occlusal forces.
- Creep refers to the slow, time-dependent deformation of a material under a constant load or stress, which can lead to dimensional changes and ultimately affect the longevity and effectiveness of the restoration.

Among the materials listed:
- Composite resin is a polymer-based material that primarily undergoes polymerization shrinkage but has relatively low creep under occlusal forces.
- Dental amalgam is a metallic restorative material known for its metallic plasticity, which means it can undergo permanent deformation under constant stress, i.e., creep. This happens because amalgam is a soft metal alloy that slowly deforms over time when subjected to repetitive occlusal loads.
- Glass ionomer cement has some degree of plastic deformation but is generally more brittle and less prone to creep compared to amalgam.
- Ceramic materials are extremely rigid and brittle; therefore, they exhibit minimal or no creep but are more prone to fracture.

Therefore, the correct answer is dental amalgam, as it is the most prone to creep under occlusal forces due to its metallic, malleable nature.

Key points:
- Creep is time-dependent deformation under constant stress.
- Dental amalgam shows significant creep due to its metallic plasticity.
- Composite resins and ceramics are more dimensionally stable under occlusal forces.
- Glass ionomer cements are brittle with minimal creep but lower strength.

Reference: Sturdevant's Art and Science of Operative Dentistry, 7th Edition, Chapter 14, Page 372-375