What is the best clinical determinant of active root surface caries?

Correct answer: A. A soft, tacky area detected on gentle tactile examination

• A. CORRECT. Root caries is diagnosed by combined VISUAL and TACTILE examination. The definitive sign of an ACTIVE lesion is a SOFT, tacky surface that a blunt probe indents under gentle pressure, typically light brown or yellowish and matte. An arrested lesion, by contrast, is hard, dark brown or black, and shiny.
• B. Cold sensitivity is non-specific — it accompanies recession and dentine hypersensitivity in the complete absence of caries.
• C. Sensitivity to sweets suggests exposed dentine but does not establish that a lesion is present or active.
• D. Radiographs are a useful adjunct, particularly proximally, but cervical burnout mimics root caries on film and buccal or lingual lesions are frequently invisible.

Note: Use GENTLE pressure. A sharp explorer forced into a demineralised but remineralisable surface cavitates it iatrogenically and converts a reversible lesion into one requiring restoration.