Hounsfield Unit
A unit of y-ray attenuation used for CT-scans as a measurement of bone density. Each pixel is assigned a value on a scale on which air is -1000, water 0, and compact bone +1000.
In dentistry exists a proposal to use bone density as a determinant for clinical success (Misch CE, Contemporary Implant Dentistry, St. Louis Mosby, 1999: 109-118).
D1: > 1250 HU
D2: 850-1250 HU
D3: 350-850 HU
D4: 150-350 HU
D5: < 150 HU