Hanna Dental Clinic

Cavitational Osteonecrosis


Neuralgia Inducing Cavitational Osteonecrosis (NICO) is basically a hollow place in bone that produces pain.  A cavitation (another word for NICO that literally means “hole”) contains dead or starved bone resulting from poor blood flow following some kind of initiating factor.  Pathogens (“bugs”) are also present in these cavitations which release highly toxic waste products that can have detrimental effects to the heart, kidney, uterus, immune, nervous, and endocrine systems.  Some investigations have found reservoirs of heavy metals (eg. mercury) present as well, especially in patients with mercury amalgam fillings in their mouths.  Although this phenomenon is difficult to diagnose because it doesn’t always appear on a dental x-ray and can be asymptomatic for years, the disease has been around for a long time under many different names such as Ratner bone cavities and maxillofacial osteonecrosis.  In 1915, G. V. Black first described these jawbone lesions as follows: “An osteomyelitis-like bone disease which seemed not to be a true infection, but rather a slow, progressive, unexplained death of cancellous bone and marrow, cell by cell.”




NICO most likely occurs due to a combination of initiating events, predisposing factors, and risk factors.

  • Initiating events:
    • Physical trauma (such as a tooth extraction, vasoconstrictors in dental freezing, root canal treatment)
    • Bacterial trauma (such as periodontal disease, abcesseses, or root canal bacteria)
    • Toxic trauma (such as dental materials or bacterial toxins)
  • Predisposing factors: such as blood clotting disorders (eg. thromophilia, hypofibrinolysis), age (arteries in the jaw tend to decrease in size with age), chemotherapy or radiation treatment for cancer, rheumatoid arthritis, bone dysplasia, changes in atmospheric pressures, osteoporosis, thyroid dysfunction, systemic lupus erythematosis, sickle cell anemia, gout and physical inactivity
  • Risk factors: such as smoking, pregnancy, alcoholism, and long-term cortisone usage

When an initiating event occurs, the body responds by creating a mild inflammation in the bone and marrow which releases chemicals to increase local blood clotting.  This design works well under normal circumstances to deal with trauma (eg. if you cut your finger), however when there is already a compromised blood flow the clotting can lead to painful infarction and marrow death.  Some dental freezing contains a vasoconstrictor which decreases blood flow and may worsen the situation even more.



NICO may occur in any bone in the body but hips, knees, and jaws are most common.  The majority of cavitational lesions in the jaw tend to occur at wisdom teeth extraction sites (top or bottom) and these lesions can spread to other areas to initiate further cavities.



Jaw cavitations can be asymptomatic or may trigger pain in other parts of the face and head or even distant parts of the body.  Osteonecrosis (bone death) may be occurring asymptomatically for years before symptoms show up.  If there is pain present, it is often difficult to describe and localize.  It may be a dull ache or there will be symptoms that mimic atypical facial neuralgia, trigeminal neuralgia, headache, sinusitis, phantom toothache pain or chronic fatigue.  Although the pain is usually intermittent and variable, it seems to increases in intensity, area and frequency slowly over time.  The typical NICO patient has pain for about 6 years before a proper diagnosis is made.  Some patients describe an occasional sour taste in the mouth.




NICO in the jaws may occur with men or women at any age however it tends to occur more commonly in middle-aged women.



Currently, there is no known treatment that is completely and consistently effective however there are several therapies that may reduce or eliminate symptoms in some patients but these treatments may need to be performed several times every few weeks.  NICO tends to recur and/or spread to other jawbone sites even after treatment.  Methods for preventing routine extractions from becoming osteonecrotic lesions are in early development.



If you are having symptoms which are similar to the above description of NICO, or simply have questions regarding this disease, please don’t hesitate to contact us.