|This article needs additional citations for verification. (August 2010)|
Surgical extraction of an impacted molar. NIDCR.
A dental extraction (also referred to as exodontia) is the removal of a tooth from the mouth. Extractions are performed for a wide variety of reasons, including tooth decay that has destroyed enough tooth structure to render the tooth non-restorable. Extractions of impacted or problematic wisdom teeth are routinely performed, as are extractions of some permanent teeth to make space for orthodontic treatment.
Historically, dental extractions have been used to treat a variety of illnesses, as well as a method of torture to obtain forced confessions. Before the discovery of antibiotics, chronic tooth infections were often linked to a variety of health problems, and therefore removal of a diseased tooth was a common treatment for various medical conditions. Instruments used for dental extractions date back several centuries. In the 14th century, Guy de Chauliac invented the dental pelican, which was used through the late 18th century. The pelican was replaced by the dental key which, in turn, was replaced by modern forceps in the 20th century. As dental extractions can vary tremendously in difficulty, depending on the patient and the tooth, a wide variety of instruments exist to address specific situations.
The most common reason for extraction is tooth damage due to breakage or decay. There are additional reasons for tooth extraction:
- Severe tooth decay or infection (acute or chronic alveolar abscess). Despite the reduction in worldwide prevalence of dental caries, still it is the most common reason for extraction of (non-third molar) teeth with up to two thirds of extractions.
- Supernumerary teeth which are blocking other teeth from coming in.
- Severe gum disease which may affect the supporting tissues and bone structures of teeth.
- In preparation for orthodontic treatment (braces)
- Teeth in the fracture line
- Teeth which cannot be restored endodontically
- Fractured teeth
- Supenumerary, supplementary or malformed teeth
- Prosthetics; teeth detrimental to the fit or appearance of dentures
- Insufficient space for wisdom teeth (impacted third molars). Although many dentists remove asymptomatic impacted third molars, Both American and British Health Authorities recommended against this routine procedure, unless there are evidences for disease in the impacted tooth or the near environment. The American Public Health Association, for example, adopted a policy, Opposition to Prophylactic Removal of Third Molars (Wisdom Teeth) because of the large number of injuries resulting from unnecessary extractions.
- Cosmetic; teeth of poor appearance, unsuitable for restoration
- Receiving radiation therapy to the head and neck area may require extraction of teeth in the field of radiation.
- Deliberate, medically unnecessary, extraction as a form of physical torture.
- It was once a common practice to remove the front teeth of institutionalized psychiatric patients who had a history of biting.
- Reduced cost compared to other treatments
Extractions are often categorized as "simple" or "surgical".
Simple extractions are performed on teeth that are visible in the mouth, usually under local anaesthetic, and require only the use of instruments to elevate and/or grasp the visible portion of the tooth. Typically the tooth is lifted using an elevator, and using dental forceps, rocked back and forth until the periodontal ligament has been sufficiently broken and the supporting alveolar bone has been adequately widened to make the tooth loose enough to remove. Typically, when teeth are removed with forceps, slow, steady pressure is applied with controlled force.
Surgical extractions involve the removal of teeth that cannot be easily accessed, either because they have broken under the gum line or because they have not erupted fully. Surgical extractions almost always require an incision. In a surgical extraction the doctor may elevate the soft tissues covering the tooth and bone and may also remove some of the overlying and/or surrounding jawbone tissue with a drill or osteotome. Frequently, the tooth may be split into multiple pieces to facilitate its removal. Surgical extractions are usually performed under a general anaesthetic.
Immediately following the removal of a tooth, bleeding or just oozing very commonly occurs. Pressure is applied by biting on a gauze swab, and a thrombus (blood clot) forms in the socket (hemostatic response). Sometimes 30 minutes of continuous pressure is required to fully arrest bleeding. Talking instead of keeping constant pressure on the socket is a common reason that bleeding might not stop. Coagulopathies (clotting disorders, e.g. hemophilia) are sometimes discovered for the first time if a person has had no other surgical procedure in their life, but this is rare. Sometimes the blood clot can be dislodged, triggering more bleeding and formation of a new blood clot, or leading to a dry socket (see complications). Some oral surgeons routinely scrape the walls of a socket to encourage bleeding in the belief that this will reduce the chance of dry socket, but there is no evidence that this practice works.
The chance of further bleeding reduces as healing progresses, and is unlikely after 24 hours. The blood clot is covered by epithelial cells which proliferate from the gingival mucosa of socket margins, taking about 10 days to fully cover the defect. In the clot, neutrophils the macrophages are involved as an inflammatory response takes place. The proliferative and synthesizing phase next occurs, characterized by proliferation of osteogenic cells from the adjacent bone marrow in the alveolar bone. Bone formation starts after about 10 days from when the tooth was extracted. After 10-12 weeks, the outline of the socket is no longer apparent on an x-ray image. Bony remodeling as the alveolus adapts to the edentulous state occurs in the longer term as the alveolar process slowly resorbs. In maxillary posterior teeth, the degree of pneumatization of the maxillary sinus may also increase as the antral floor remodels.
- Infection: The dentists may opt to prescribe antibiotics pre- and/or post-operatively if they determine the patient to be at risk.
- Prolonged bleeding: The dentist has a variety of means at their disposal to address bleeding; however, small amounts of blood mixed in the saliva after extractions are normal, even up to 72 hours after extraction. Usually, however, bleeding will almost completely stop within eight hours of the surgery, with only minuscule amounts of blood mixed with saliva coming from the wound. A gauze compress will significantly reduce bleeding over a period of a few hours.
- Swelling: Often dictated by the amount of surgery performed to extract a tooth (e.g. surgical insult to the tissues both hard and soft surrounding a tooth). Generally, when a surgical flap must be elevated (i.e. and the periosteum covering the bone is thus injured), minor to moderate swelling will occur. A poorly-cut soft tissue flap, for instance, where the periosteum is torn off rather than cleanly elevated off the underlying bone, will often increase such swelling. Similarly, when bone must be removed using a drill, more swelling is likely to occur.
- Bruising: Bruising may occur as a complication after tooth extraction. Bruising is more common in older people or people on aspirin or steroid therapy. It may take weeks for bruising to disappear completely.
- Sinus exposure and oral-antral communication: This can occur when extracting upper molars (and in some patients, upper premolars). The maxillary sinus sits right above the roots of maxillary molars and premolars. There is a bony floor of the sinus dividing the tooth socket from the sinus itself. This bone can range from thick to thin from tooth to tooth from patient to patient. In some cases it is absent and the root is in fact in the sinus. At other times, this bone may be removed with the tooth, or may be perforated during surgical extractions. The doctor typically mentions this risk to patients, based on evaluation of radiographs showing the relationship of the tooth to the sinus. It is important to note that the sinus cavity is lined with a membrane called the Sniderian membrane, which may or may not be perforated. If this membrane is exposed after an extraction, but remains intact, a "sinus exposed" has occurred. If the membrane is perforated, however, it is a "sinus communication". These two conditions are treated differently. In the event of a sinus communication, the dentist may decide to let it heal on its own or may need to surgically obtain primary closure—depending on the size of the exposure and the likelihood of the patient to heal. In both cases, a resorbable material called "gelfoam" is typically placed in the extraction site to promote clotting and serve as a framework for granulation tissue to accumulate. Patients are typically provided with prescriptions for antibiotics that cover sinus bacterial flora, decongestants, and careful instructions to follow during the healing period.
- Nerve injury: This is primarily an issue with extraction of third molars, but can occur with the extraction of any tooth should the nerve be close to the surgical site. Two nerves are typically of concern, and are found in duplicate (one left and one right): 1. the inferior alveolar nerve, which enters the mandible at the mandibular foramen and exits the mandible at the sides of the chin from the mental foramen. This nerve supplies sensation to the lower teeth on the right or left half of the dental arch, as well as sense of touch to the right or left half of the chin and lower lip. 2. The lingual nerve (one right and one left), which branches off the mandibular branches of the trigeminal nerve and courses just inside the jaw bone, entering the tongue and supplying sense of touch and taste to the right and left half of the anterior 2/3 of the tongue as well as the lingual gingiva (i.e. the gums on the inside surface of the dental arch). Such injuries can occur while lifting teeth (typically the inferior alveolar), but are most commonly caused by inadvertent damage with a surgical drill. Such injuries are rare and are usually temporary, but depending on the type of injury (i.e. Seddon classification: neuropraxia, axonotmesis, & neurotmesis), can be prolonged or even permanent.
- Displacement of tooth or part of the tooth into the maxillary sinus (upper teeth only). In such cases, the tooth or tooth fragment must almost always be retrieved. In some cases, the sinus cavity can be irrigated with saline (antral lavage) and the tooth fragment may be brought back to the site of the opening through which it entered the sinus, and may be retrievable. At other times, a window must be made into the sinus in the Canine fossa—a procedure referred to as a "Caldwell-Luc".
- Dry socket (Alveolar osteitis) is a painful phenomenon that most commonly occurs a few days after the removal of mandibular (lower) wisdom teeth. It typically occurs when the blood clot within the healing tooth extraction site is disrupted. More likely, alveolar osteitis is a phenomenon of painful inflammation within the empty tooth socket because of the relatively poor blood supply to this area of the mandible (which explains why dry socket is usually not experienced in other parts of the jaws). Inflamed alveolar bone, unprotected and exposed to the oral environment after tooth extraction, can become packed with food and debris. A dry socket typically causes a sharp and sudden increase in pain commencing 2–5 days following the extraction of a mandibular molar, most commonly the third molar. This is often extremely unpleasant for the patient; the only symptom of dry socket is pain, which often radiates up and down the head and neck. A dry socket is not an infection, and is not directly associated with swelling because it occurs entirely within bone – it is a phenomenon of inflammation within the bony lining of an empty tooth socket. Because dry socket is not an infection, the use of antibiotics has no effect on its rate of occurrence. The risk factor for alveolar osteitis can dramatically increase with smoking after an extraction.
- Bone fragments: Particularly when extraction of molars is involved, it is not uncommon for the bones which formerly supported the tooth to shift and in some cases to erupt through the gums, presenting protruding sharp edges which can irritate the tongue and cause discomfort. This is distinguished from a similar phenomenon where broken fragments of bone or tooth left over from the extraction can also protrude through the gums. In the latter case, the fragments will usually work their way out on their own. In the former case, the protrusions can either be snipped off by the dentist, or eventually the exposed bone will erode away on its own.
- Trismus: Jaw joints and chewing muscles may become sore after tooth extraction and it may become difficult for the patient to open the mouth.
- Loss of a tooth: If an extracted tooth slips out of the forceps, it may be swallowed or inhaled. The patient may be aware of swallowing it, or they may cough, which suggests inhalation of the tooth. The patient must be referred to for a chest Xray in hospital if a tooth cannot be found. If it has been swallowed, no action is necessary as it usually passes through the alimentary canal without doing any harm. But if it has been inhaled, an urgent operation is necessary to recover it from the airway or lung before it causes serious complications such as pneumonia or a lung abscess.
- Luxation of the adjacent tooth: The force application during extraction procedure must strictly be limited to the tooth that requires the extraction. Most case of surgical extraction procedures require that the forces are diverted from the tooth itself to areas such as bone surrounding the tooth to ensure adequate bone removal before proceeding any further in the extraction procedure. Either ways the forces applied by various instruments during both simple and complicated surgical procedure may loosen the teeth present both in-front or behind of the tooth depending upon the impact, direction and location of the force being applied, and that happening only if the forces divert form the actual tooth that needs extraction. Such deleterious forces may weaken the anchorage of adjacent teeth from within their boney socket and hence result in weakening of the adjacent teeth.
- Extraction of the wrong tooth: Misdiagnosis, altered tooth morphology, faulty clinical examination, poor patient history, undetected / unmentioned previous extractions that may predispose the operator to consider another tooth to be a replicate of the one previously extracted are a few causes of extraction of a wrong tooth.
- Dental x-ray
- Endodontic therapy
- Gum disease
- Oral and maxillofacial surgery
- Tooth abscess
- Focal infection theory
- Zadik Y, Sandler V, Bechor R, Salehrabi R (August 2008). "Analysis of factors related to extraction of endodontically treated teeth". Oral Surg Oral Med Oral Pathol Oral Radiol Endod 106 (5): e31–5. doi:10.1016/j.tripleo.2008.06.017. PMID 18718782.
- Hollins, Carole (2008). Levison's Textbook for Dental Nurses. ISBN 978-1-4051-7557-9
- Zadik Y, Levin L (April 2006). "[Decision making of Hebrew University and Tel Aviv University Dental Schools graduates in every day dentistry--is there a difference?]". Refuat Hapeh Vehashinayim (in Hebrew) 23 (2): 19–23, 65. PMID 16886872.
- Zadik Y, Levin L (April 2007). "Decision making of Israeli, East European, and South American dental school graduates in third molar surgery: is there a difference?". J. Oral Maxillofac. Surg. 65 (4): 658–62. doi:10.1016/j.joms.2006.09.002. PMID 17368360.
- Morant H (April 200). "UK government wants GMC to be given stronger powers". British Medical Journal 320 (7239): 890A. doi:10.1136/bmj.320.7239.890. PMC 1117823. PMID 10741982. Retrieved 2008-08-08.
- "Opposition to Prophylactic Removal of Third Molars (Wisdom Teeth)". Policy Statement Database. American Public Health Association. 2008-10-28. Retrieved 2010-02-24.
- C. Thomas Gualtieri. Brain injury and mental retardation: psychopharmacology and neuropsychiatry.
- Antonio Nanci (editor) (2007). Oral histology : development, structure, and function. (7th ed. ed.). St. Louis, Mo.: Mosby. ISBN 9780323045575.