Which structure is radiolucent?

Which structure is radiolucent?

• A. Crowns
• B. Gutta-percha
• C. Nerve
• D. Restorations

Answer: (C)

Radiolucency on a dental radiograph means a structure that attenuates X-rays less, so it appears dark. The nerve within the tooth—the dental pulp—is soft tissue with little mineral content, so it does not block X-rays as much as surrounding dentin and enamel. As a result, the pulp space and root canal show up as dark, radiolucent areas on the film, bounded by radiopaque bone and hard tooth tissues. In contrast, crowns, gutta-percha, and most restorations are dense materials that block X-rays and appear white or light. Therefore, the structure that is radiolucent is the nerve (pulp).

Radiolucency on a dental radiograph means a structure that attenuates X-rays less, so it appears dark. The nerve within the tooth—the dental pulp—is soft tissue with little mineral content, so it does not block X-rays as much as surrounding dentin and enamel. As a result, the pulp space and root canal show up as dark, radiolucent areas on the film, bounded by radiopaque bone and hard tooth tissues. In contrast, crowns, gutta-percha, and most restorations are dense materials that block X-rays and appear white or light. Therefore, the structure that is radiolucent is the nerve (pulp).