Neuralgia-inducing cavitational osteonecrosis (NICO) refers to presence of cavitations in jaw bones (mandible and/or maxilla

Maxilla

The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...

) in conjunction with chronic facial neuralgia

Neuralgia

Neuralgia is pain in one or more nerves that occurs without stimulation of pain receptor cells. Neuralgia pain is produced by a change in neurological structure or function rather than by the excitation of pain receptors that causes nociceptive pain. Neuralgia falls into two categories: central...

. 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.

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

Infection

An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...

, or, in more modern versions of the theory, susceptibility to thrombosis

Thrombosis

Thrombosis is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel is injured, the body uses platelets and fibrin to form a blood clot to prevent blood loss...

.

The suggested treatment for NICO involves oral surgery consisting of decortication

Decortication

Decortication is a medical procedure involving the surgical removal of the surface layer, membrane, or fibrous cover of an organ. The procedure is usually performed when the lung is covered by a thick, inelastic pleural peel restricting lung expansion. In a non-medical aspect, decortication is...

 and debridement

Debridement

Debridement is the medical removal of a patient's dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue...

 of bone via curettage

Curettage

Curettage, in medical procedures, is the use of a curette to remove tissue by scraping or scooping.Curettages are also a declining method of abortion. It has been replaced by vacuum aspiration over the last decade....

 to remove dead bone tissue.

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:

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.

Controversy

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

Evidence-based medicine

Evidence-based medicine or evidence-based practice aims to apply the best available evidence gained from the scientific method to clinical decision making. It seeks to assess the strength of evidence of the risks and benefits of treatments and diagnostic tests...

 that does not suffer from methodological flaws. It has been rejected as quackery

Quackery

Quackery is a derogatory term used to describe the promotion of unproven or fraudulent medical practices. Random House Dictionary describes a "quack" as a "fraudulent or ignorant pretender to medical skill" or "a person who pretends, professionally or publicly, to have skill, knowledge, or...

 by some but not all dentists and maxillofacial surgeons.

See also

• Trigeminal neuralgia
  Trigeminal neuralgia
  Trigeminal neuralgia , tic douloureux is a neuropathic disorder characterized by episodes of intense pain in the face, originating from the trigeminal nerve. It has been described as among the most painful conditions known...
  
  
• Atypical trigeminal neuralgia
  Atypical trigeminal neuralgia
  Atypical Trigeminal Neuralgia , or Type 2 Trigeminal Neuralgia, is a rare form of Trigeminal neuralgia, a disorder of the fifth cranial nerve. This form of neuralgia is difficult to diagnose, as it is rare and the symptoms overlap with several other disorders...
  
  
• Osteonecrosis of the jaw
  Osteonecrosis of the jaw
  Osteonecrosis of the jaw is a severe bone disease that affects the maxilla and the mandible. Various forms of ONJ have been described over the last 160 years, and a number of causes have been suggested in the literature...
  
  

External links

• Cavitational Osteopathosis, NICO, and Biological Dentistry - from Quackwatch
  Quackwatch
  Quackwatch is an American non-profit organization founded by Stephen Barrett with the stated aim being to "combat health-related frauds, myths, fads, fallacies, and misconduct" and with a primary focus on providing "quackery-related information that is difficult or impossible to get elsewhere."...
  
  
• http://www.maxillofacialcenter.com/NICOclinical.html Reality of NICO
• http://www.hallvtox.dircon.co.uk/cavroot.html Surgery that specialise in NICO