Which statement describes the effect of a cup-shaped cavity on the dentin bridge?

• A. It causes rotation of the restoration and wedging on the dentin bridge
• B. It improves enamel color
• C. It increases occlusal bite
• D. It reduces friction

Answer: (A)

A cup-shaped cavity changes how the restoration seats on the dentin surface. Its curved floor can cause the restoration to twist a bit as it is pressed into place, creating a rotating movement and a wedging action at the dentin bridge interface. This mechanical stress on the reparative dentin can threaten the integrity of the dentin bridge, leading to distortion or damage rather than improving other properties. In contrast, color changes of enamel, alterations in the occlusal bite, or reductions in friction aren’t related to how seating forces affect the dentin bridge in this cavity shape.