Which description defines Miller's Degree 2 tooth mobility?

• A. No movement
• B. Physiological movement
• C. Greater than 1 mm horizontal movement with vertical movement
• D. Greater than 1 mm of horizontal movement

Answer: (D)

Miller’s mobility grading measures how much a tooth moves horizontally in the socket when a gentle buccal-lingual force is applied. Degree 2 specifically means the tooth has more than 1 mm of horizontal movement, but there is no vertical depression of the tooth into the socket. This is different from the highest grade, where there is both significant horizontal movement and a vertical drop, and from the lowest grade, where movement is up to 1 mm horizontally or essentially none.

So, the description that fits degree 2 is horizontal movement greater than 1 mm without any vertical movement. Normal, tiny movement can occur biologically, but that wouldn’t meet the criteria for degree 2.