Maxillofacial Osteonecrosis, Signs & Symptoms
©The Maxillofacial Center for Diagnostics & Research
Other Links Causes of NICO NICO Home Page Home Page		Clinical Features Who & Where Signs & Symptoms  Cavitations Local Anesthesia Test Electro-Acupuncture Associated Diseases Diagnostic Imaging
Hollow mandibular space (cavitation) seen in subpontic zone of old extraction site (bridge is removed).

The Maxillofacial Center, 165 Scott Avenue, Suite 100, Morgantown, WV 26508 USA
Phone: 304-292-4429   Fax: 304-291-5149    Email: MFC@aol.com

Who Is Affected and Where?

Patient Age & Gender.  Maxillofacial osteonecrosis (NICO) has been microscopically confirmed in patients as young as 14 years of age and as old as 94, and has been reported in both genders.  However, three-fourths of patients are 35-64 years of age and three-fourths are women.  These age and gender predilections are similar for patients with pain and those without pain.  

Location of Lesions.  Jawbone sites most often involved, in decreasing order of frequency, are the mandibular molar/retromolar areas, the maxillary molar/tuberosity areas, and the maxillary cuspid/lateral incisor areas (Table 1). Third molar (wisdom tooth) sites account for 45% of all jawbone involvement.  The vascular inflow of the mandible is quite different from the maxilla and one would not, therefore, expect even distribution of a vascular disease , but osteonecrosis is generally a disease of infarction and thrombosis of small vessels ischemic damage is more likely to occur in the distal portions

Most maxillofacial lesions are in old extraction sites, but another common presentation is a radiographically successful endodontic procedure which continues to be painful after therapy, even after extraction.  While the great majority of facial cases occur in the alveolar bone, i.e. the bone containing the teeth, osteonecrosis can affect the walls of the sinuses, walls of the external ear canal (malignant otitis externa), and the TMJ  or jaw joint (avascular necrosis of the condyle).  

Multiple Sites are Often Involved. One-third of NICO patients have more than a single quadrant involved, not necessarily at the same time, and 10% have lesions in all four quadrants.  This is not unexpected, as it has long been known that 50-80% of hip cases eventually involve the opposite femoral head.  In our experience, the more generalized the condition, the more likely the jawbone patient is to suffer from multiple risk factors, including hyperthrombotic disorders.

Signs & Other Symptoms

Few Surface Tissue Changes.  Maxillofacial osteonecrosis produce only subtle, if any, inflammatory changes of overlying soft tissues, including transient erythema (redness) and edema (swelling), but microscopic analysis of the overlying soft tissues demonstrates mild to moderate numbers of chronic inflammatory cells beneath the epithelium.  

Tenderness (Pain on Touching). Most maxillary lesions, especially those of the tuberosities (behind the upper wisdom teeth), are tender to palpation or can be aggravated by pressure, perhaps even triggering a "jump sign" similar to that elicited when palpating myofascial trigger points (see Travell & Simons). Mandibular lesions are more difficult to identify with digital pressure, presumably because of the greater density of the cortical bone.  A lack of local tenderness in the area of pain or of referring pain makes the diagnosis more difficult but does not exclude underlying marrow disease.  McMahon et al (1998) have shown that chronic inflammatory cells are found in small numbers beneath the mucosa in these areas of tenderness, presumably because of neurogenic inflammatory reactions.

In 1995 Friedman found focal areas of alveolar bone tenderness within the quadrant of pain in 15 of 18 patients with atypical facial neuralgia/pain; 17 of the 18 patients demonstrated a focus of increased mucosal temperature in the quadrant of pain.

Pain (Without Touching). When pain is associated with ischemic osteonecrosis of the jaws it is usually diagnosed as atypical facial neuralgia/pain (67% of all pain-associated cases) or trigeminal neuralgia (10%) until a jawbone lesion is discovered.⁶¹ An additional 23% are diagnosed with various headaches, sinusitis or phantom toothache/pain. The typical NICO patient has had his or her pain for approximately 6 years (range: 1 month to 32 years) before a jawbone biopsy confirms the presence of ischemic osteonecrosis or low-grade osteomyelitis.⁶¹ The pain, and presumably the ischemic process, appears to be very slowly progressive over time, with increasing pain, increasing frequency of pain and increasing areas of involvement. The pain is often intermittent and may vary in extent, location and character over time. It is often difficult for the patient to describe and localize.

The pain in this disease can be produced by a variety of factors, such as ischemia of the nerves, fluid or gasseous pressures on the nerves, distended blood vessels, inflammatory mediators, damage to the nerves from chronic exposure to the toxins of dead or inflamed tissues.  It should not be surprising, then, that a variety of types of pain occur.  Most patients feel a deep ache or sharp pain deep in the bone.  This is often difficult to localize and may, in fact, move about from day to day or week to week (remember, the disease is a fluid/pressure phenomenon with small infarctions occurring over time).   Pain episodes may be separated by days or weeks without pain. Another common pain type is a very sharp, lancinating pain shooting up to the eye or along the edge of the nose or back to the ear, perhaps with temporary secondary pain in those sites.  This pain may or may not be triggered by touching a certain part of the alveolar bone or overlying facial skin.  Some patients describe their deep pain as "annoying" or "uncomfortable" rather than true pain, but these generally will go on to more severe pain over time.

Two abiding features of NICO pain are: the pain responds poorly to pain killing medications (except morphine) while likely to respond well, temporarily, to "anti-seizure" medicines, such as Tegretol and Neurontin; the pain in approximately 15% of cases will disappear for several days, weeks or months after injection of the primary site of pain with local anesthetics.  The reason for the former phenomenon is unknown, but may be related to myelin (nerve sheath) damage from the toxins of the diseased marrow.  The latter phenomenon may have to do with the fact that intraosseous blood flow is so slowed in some individuals that the anesthetic remains in place for long periods of time.  A third feature of NICO is that a local dental anesthetic injected into the periosteal tissues above the site of diseased marrow almost always reduces or completely eliminates the pain.    

Other Sensations.  It is quite common for a patient to complain of an annoying pressure sensation in the area of involvement.  The pressure may, in fact, be a real phenomenon, as osteonecrosis is associated with internal bone pressures much higher than normal.  While the jaw cases have not been analyzed in this regard, surgeons have experienced lesions with enough pressure to produce an audible release of air when the cortex was surgically removed.  Occasionally, necrotic marrow debris will come "flying" out of the cavitation.  An additional common sensation in maxillofacial osteonecrosis patients is a strong sensation of burning deep in the bone.  This may be indicative of damage to the nerves themselves, but that has not yet been established.

Diseases Associated with Osteonecrosis.  One of the frightening features of ischemic osteonecrosis is the very large number of systemic and local diseases and factors capable of damaging the bone marrow.  Jones has listed them for years, with the list expanding dramatically in recent years (Table 2).  For more information, click above on the link to Causes of NICO.

Sinus involvement.  Recurrent sinusitis may involve the bony walls and floor of the maxillary sinus, allowing bacteria and/or inflammatory toxins into alveolar bone on a recurring basis and perpetuating osteomyelitis/osteonecrosis of multiple maxillary sites. Roberts et al have suggested injecting a radiopaque dye into the maxillary sinus, with periapical radiographs taken at 20, 40, and 60 minutes, as a means by which to identify areas of sinus wall or floor perforation not otherwise apparent. Other walls are also affected, but less frequently. Some patients have shown considerable destruction of the infraorbital bone, and the lateral nasal wall appears to be especially susceptible, perhaps because of the popular use of corticosteroid nasal sprays.

Abnormal Responses to Local Anesthesia

Pain response to local anesthetics is used as a diagnostic tool in maxillofacial osteonecrosis (anesthetic confirmation, diagnostic local anesthesia).  Box appears to be the first to report the use of anesthetic confirmation, and recent authors have reaffirmed its usefulness, but it was Ratner & colleagues and McMahon and colleagues who developed a specific protocol of diagnostic local anesthetic injections for localizing the lesion(s) and determining the association between the diseased bone and the pain dilemma. In sorting out pain-producing mandibular pathology, this anesthesia/hyperesthesia test depends on localizing small zones of unanesthetized gingiva in an area which would normally be expected to be anesthetized after inferior alveolar and long buccal nerve blocks. These tissues are then directly infiltrated in order to obtain complete analgesia and checked for "full terminus" anesthesia (complete, to the lip).

Pain-producing maxillary pathology, whether dental or osseous in origin, can be assessed by beginning anteriorly and selectively infiltrating buccally and palatally, proceeding posteriorly, until the pain has been extinguished. Because of the many snares of referred trigeminal pain phenomena, the reader is encouraged to review Ratner et al and McMahon et al for further details. The reader is especially reminded to use only anesthetic solutions without vasoconstrictors, in order to avoid further compromise of a marginally inadequate medullary blood flow.

Electro-Acupuncture Testing

A certain number of dentists submitting biopsied tissue samples for maxillofacial osteonecrosis evaluation seem able to localize intramedullary disease through the identification of electrical disturbances of the mucosal surface. This is done through an electronic sensing device called a Computron. These practitioners may combine oral findings with diagnostic acupuncture techniques, a practice initiated by Voll and often called EAV, or electro-acupuncture according to Voll. Much research needs yet to be performed to more substantially validate this technique, but an informal review of tissue submitted for microscopic interpretation has shown that ischemic and inflammatory marrow disease is identified positively at the same level as that of practitioners using more conventional diagnostic techniques: somewhat more than 90% of samples submitted with a NICO or maxillofacial osteonecrosis clinical diagnosis prove to be so on microscopic evaluation.

Table 1: Location of 2,301 NICO lesions as reported on biopsy request forms from 1,333 patients with facial pain. Numbers represent the proportion (%) of all cases found at a specific site, first surgery only.

               * includes tuberosity and retromolar areas