Neuralgia-inducing cavitational osteonecrosis (NICO)

Neuralgia-inducing cavitational osteonecrosis (NICO)

Neuralgia-inducing cavitational osteonecrosis (NICO) refers to presence of cavitations in jaw bones (mandible and/or maxilla) in conjunction with chronic facial neuralgia. The concept implies direct and causal relationship between the bone pathology (cavitations) and pain itself. Pain in this setting is commonly described as atypical facial neuralgia and is chronic in nature. Cavitations represent areas of necrotic (dead) bone.[1][2][3]


Suggested Causes and Treatment

The cause of NICO is allegedly avascular osteonecrosis (AO) (also known as ischemic osteonecrosis). This bone ischemia would result from a chronic low-grade infection,[3] or, in more modern versions of the theory, susceptibility to thrombosis.[4][5]

The suggested treatment for NICO involves oral surgery consisting of decortication and debridement of bone via curettage to remove dead bone tissue.[6]

AAE Position Statement

In 1996, the Research and Scientific Affairs Committee of the American Association of Endodontists prepared the following statement to address issues raised by some endodontic patients:[7]

The NICO lesion (Neuralgia-Inducing Cavitational Osteonecrosis, also known as Ratner’s bone cavity) was first described in the dental literature in 1920 by G.V. Black. The lesion consists of ischemic osteonecrosis found in the jaws of patients with symptoms of atypical facial pain or trigeminal neuralgia. Research has shown the lesions to be difficult to diagnose. The lesion will sometimes present very subtle radiographic changes often detectable only by a technetium scan or with multiple periapical radiographs. The overlying soft tissues show no changes. Many etiologies for NICO have been suggested, but none have been substantiated through research. According to noted oral pathologist Dr. J.E. Bouquot, the typical NICO case occurs as facial pain many years after an extraction or an infection in the area. Odontogenic infections and minor trauma have been suggested as initiators, and correlations to clotting or vascular abnormalities have been made based on anecdotal associations. No scientific studies have demonstrated a causative relationship between endodontic therapy and the formation of NICO. The recommended treatment for NICO is decortication and curettage of the bony tissues. While this practice has produced relief of pain in some cases, NICO has a strong tendency to recur and to develop in other jawbone sites. Most affected sites with a postoperative NICO diagnosis have been in edentulous areas. However, some patients with long, frustrating histories of pain associated with endodontically treated teeth have been presented the treatment option of tooth extraction followed by periapical curettage in an attempt to alleviate pain. The American Association of Endodontists cannot condone this practice when NICO is suspected. Because of the lack of clear etiological data, a NICO diagnosis should be considered only as a last resort when all possible local odontogenic causes for facial pain have been eliminated. If a NICO lesion is suspected in relation to an endodontically treated tooth, if possible, periradicular surgery and curettage should be attempted, not extraction. In addition, the practice of recommending the extraction of endodontically treated teeth for the prevention of NICO, or any other disease, is unethical and should be reported immediately to the appropriate state board of dentistry.


NICO remains a controversial diagnostic entity. The opponents argue that the concept can currently not be accepted because precise diagnostic criteria are lacking and there is no supporting scientific evidence that does not suffer from methodological flaws.[8] It has been rejected as quackery by some but not all dentists and maxillofacial surgeons.[9][10]

See also


  1. ^ Ratner EJ, Person P, Kleinman DJ, Shklar G, Socransky SS (July 1979). "Jawbone cavities and trigeminal and atypical facial neuralgias". Oral Surg. Oral Med. Oral Pathol. 48 (1): 3–20. doi:10.1016/0030-4220(79)90229-9. PMID 287984. 
  2. ^ Roberts AM, Person P (October 1979). "Etiology and treatment of idiopathic trigeminal and atypical facial neuralgias". Oral Surg. Oral Med. Oral Pathol. 48 (4): 298–308. doi:10.1016/0030-4220(79)90027-6. PMID 291856. 
  3. ^ a b Bouquot JE, Roberts AM, Person P, Christian J (March 1992). "Neuralgia-inducing cavitational osteonecrosis (NICO). Osteomyelitis in 224 jawbone samples from patients with facial neuralgia". Oral Surg. Oral Med. Oral Pathol. 73 (3): 307–19; discussion 319–20. doi:10.1016/0030-4220(92)90127-C. PMID 1545963. 
  4. ^ Gruppo R, Glueck CJ, McMahon RE, et al. (May 1996). "The pathophysiology of alveolar osteonecrosis of the jaw: anticardiolipin antibodies, thrombophilia, and hypofibrinolysis". J. Lab. Clin. Med. 127 (5): 481–8. doi:10.1016/S0022-2143(96)90065-7. PMID 8621985. 
  5. ^ Glueck CJ, McMahon RE, Bouquot JE, Triplett D, Gruppo R, Wang P (November 1997). "Heterozygosity for the Leiden mutation of the factor V gene, a common pathoetiology for osteonecrosis of the jaw, with thrombophilia augmented by exogenous estrogens". J. Lab. Clin. Med. 130 (5): 540–3. doi:10.1016/S0022-2143(97)90132-3. PMID 9390643. 
  6. ^ Bouquot JE, Christian J (April 1995). "Long-term effects of jawbone curettage on the pain of facial neuralgia". J. Oral Maxillofac. Surg. 53 (4): 387–97; discussion 397–9. doi:10.1016/0278-2391(95)90708-4. PMID 7699492. 
  7. ^
  8. ^ Zuniga JR (September 2000). "Challenging the neuralgia-inducing cavitational osteonecrosis concept". J. Oral Maxillofac. Surg. 58 (9): 1021–8. doi:10.1053/joms.2000.8745. PMID 10981982. 
  9. ^ Follmar KE (2003). "Taking a stand against fraud and quackery in dentistry". J Am Coll Dent 70 (3): 4–5. PMID 14977370. 
  10. ^ Bouquot JE, McMahon RE (2003). "Charlatans in dentistry: ethics of the NICO wars". J Am Coll Dent 70 (3): 38–41. PMID 14977380. 

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