Cavitations are an area of dead bone caused by a dearth of blood flow to that part of the bone. A cavitation is a hole in the blood vessel that cannot be visually detected with the naked eye. Jawbone cavitations, also called neuralgia-inducing cavitational osteonecrosis (NICO) if they are associated with pain, are extraction sites in the jaw that have not healed.
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Cavitation (bone) Wikipedia(Text) CC BY-SA