periodontometer

per·i·o·don·tom·e·ter

(perē-ō-don-tomĕ-tĕr)
Instrument used to measure and assess the severity of periodontal disease. The term commonly denotes an instrument measuring dental mobility, but sometimes is also used for an instrument that measures pocket depth.

periodontometer (per´ēōdon-tom´ətur),

n a device used to measure the amount of tooth movement.