What is the main way to differentiate proximal carious lesions from carious lesions of the root?

• A. By location
• B. By age
• C. By color
• D. By depth

Answer: (A)

The main idea is where the decay occurs on the tooth. Proximal caries develop on the interproximal surfaces—the sides of a tooth that touch its neighbor—so their defining feature is location between teeth. Caries on the root occur on exposed root surfaces, usually where gingival recession has left cementum and dentin exposed near the cervical area. Because the surface involved (between teeth vs. root surface) is what sets these apart, location is the best way to differentiate them. In practice, proximal lesions are often seen on bitewing radiographs as radiolucencies between adjacent teeth, while root lesions appear on the root surface with a characteristic cervical location and may feel soft or leathery and show discoloration. Color and depth can vary and aren’t as reliable for distinguishing the two, and age isn’t a determining factor.