What is the mobility status of the 67-year-old Stage IV patient?

• A. Class 2 mobility
• B. No mobility
• C. Class 1 mobility
• D. Class 3 mobility

Answer: (A)

The idea being tested is how we assess how much a tooth moves in its socket, which reflects how much periodontal support is left. Mobility is graded from none to severe: up to 1 mm of horizontal movement is slight, more than 1 mm but less than 2 mm is moderate, and more than 2 mm (often with a depressible tooth) is severe.

In a 67-year-old with Stage IV periodontitis, there is substantial loss of support, so teeth are typically loosened beyond normal but not necessarily severely enough to be depressible in the socket. Moderate mobility fits this situation best, meaning the tooth shows horizontal movement greater than 1 mm but less than 2 mm. Therefore, Class 2 mobility is the most appropriate description. If there were movement over 2 mm with notable depression, that would indicate Class 3 mobility, which isn’t indicated here.