Tooth Extraction

Background

Tooth extraction is linked to dentists who perform oral surgery. Teeth that are embedded in bone (eg, impacted or wisdom teeth) must be removed by an oral and maxillofacial surgeon who is trained for 4-6 years after obtaining a dental or medical degree.

Compared with removal of an impacted tooth, tooth extraction appears to be a relatively simple technical procedure. However, both tooth extraction and removal of an impacted tooth must be performed in accordance with surgical principles that have evolved from both basic research and centuries of trial and error. Tooth extraction leaves a surgical wound, which has to heal. Accordingly, a basic understanding of wound healing is essential for performing this surgical procedure in the oral cavity.

Like any other minor surgical procedure, tooth extraction requires careful medical evaluation of the patient. Patients with diabetes, hypertension, renal disease, thyroid disease, adrenal disease, or other organ disease must be treated and their disease controlled before tooth extraction. Treatment with medications such as oral anticoagulants and bisphosphonates might cause postoperative complications and necessitate special care and medical treatment adaptation. Because the oral cavity is full of microorganisms, any surgical procedure in this area may give rise to postoperative infection, especially in immunocompromised patients. In all patients, antibacterial mouth rinse is necessary in every case of oral surgery.

Before, during, and after tooth extraction, pain management is an important issue. Medical, surgical, and legal considerations exist; for example, removing the wrong tooth is malpractice, as is breaking the jaw during extraction or causing paresthesia after extracting the mandibular third molar in close proximity to the inferior alveolar nerve without proper informed consent or suggesting an alternative such as coronectomy. In addition, complications such as postoperative bleeding due to inappropriate behavior of the patient or continuation of oral anticoagulants should be prevented as much as possible, mainly by adaptation of the medical treatment and good local hemostasis. Jaw bone necrosis due to the use of bisphosphonates should also be prevented by monitoring bone turnover before oral surgery and by avoidance of surgical extraction in patients receiving intravenous bisphosphonates.

Indications

Teeth are important for aesthetic purposes and for maintaining masticatory function. Accordingly, all efforts to avoid tooth extraction must be exhausted before the decision is made to proceed with removal of a tooth. Nevertheless, there are circumstances in which it is clear that a tooth must be extracted, such as the following:

• A tooth that cannot be restored, because of severe caries

• A mobile tooth with severe periodontal disease, pulp necrosis, or periapical abscess, for which root canal treatment is required that the patient cannot afford (or for which endodontic treatment failed)

• Overcrowding of teeth in the dental arch, resulting in orthodontic deformity ^[1]

Other conditions that may necessitate extraction include the following:

• Malposed teeth causing soft tissue trauma to the cheek

• Cracked teeth from trauma

• Supernumerary teeth

• Teeth adjacent to a pathologic lesion that must be excised

• Planned radiation or intravenous (IV) bisphosphonate treatment, warranting prophylactic extraction

• Teeth in the line of fracture

• Aesthetic considerations (eg, teeth with endogenous staining)

• Economic considerations (eg, teeth for which extensive restoration is required that the patient cannot afford ^[2] )

Contraindications

There are few contraindications for tooth extraction, and most of those that do exist can be modified by additional medical consultation and treatment. Some contraindications can be so severe that extraction should not be performed until the severity of the medical condition has been resolved.

Essentially, contraindications may be divided into local and systemic. Local contraindications are limited to the extraction sites. An example is an extraction site that was heavily exposed to radiation; if extraction is performed in the irradiated area, osteoradionecrosis results. Other local contraindication is proximity to a malignancy; extraction in the area of malignancy may increase the chances of dissemination of malignancy.

Extraction may be contraindicated in an area of infection that has not been adequately treated (eg, an impacted third molar associated with pericoronitis that is not treated with an antibiotic). Extraction may also be contraindicated when it is adjacent to the site of jaw fracture, because the teeth may be required for stabilization of the fractured bone. If the patient has very limited mouth-opening ability, extracting a tooth may be extremely difficult because of limited access to local anesthesia. ^[3]

A systemic contraindication is systemic bisphosphonate therapy for malignancy. Extraction in patients receiving such therapy results in osteochemonecrosis, which is more severe than osteoradionecrosis and is more difficult to treat. ^[4] Other systemic contraindications include brittle uncontrolled diabetes, end-stage renal and liver disease, uncontrolled leukemia, lymphoma, hypertension, cardiac dysrhythmias, and cerebrovascular accidents.

Pregnancy is a relative contraindication in the first or last trimester; extractions are deferred until after childbirth. Hemophiliac patients and those with severe platelet disorders or other bleeding diatheses should undergo extraction only after these coagulopathies have been corrected. Caution and extreme care are required before extraction in patients on long-term corticosteroids, immunosuppressants, or cancer chemotherapeutic agents. ^[5]

Clinical evaluation 

The tooth to be extracted should be examined carefully to assess the difficulty of the extraction for several parameters:

• Access to the tooth
• Mobility of the tooth
• The situation of the crown
• The situation of adjacent teeth and their crowns

Limited access to the crown due to limited mouth opening might complicate the procedure. An artificial crown or a large crown filling in the adjacent teeth might endanger its stability following the extraction, and special attention should be given to that situation.

Radiographic examination of the extracted tooth

A periapical or panoramic radiograph provides information regarding the whole tooth, including its roots and vital structures. The root configuration and the condition of the surrounding bone should be carefully checked. In cases of root proximity to the inferior dental nerve, cone beam computed tomography (CBCT) should be performed in order to determine the best procedure for the patient.

Patient and surgeon preparation

Surgeons must prevent inadvertent injury or transmission of infection to their patients or to themselves. The principle of universal precautions states that all patients must be viewed as having bloodborne diseases that can be transmitted to the surgical team and other patients. To prevent this transmission, surgical gloves, surgical mask, and eyewear with side-shields are required.  In addition, most authorities recommend that the surgical team wear long-sleeved gowns, which should be changed when they become visibly soiled

Equipment

Tooth extraction is performed either in a dental office by a dentist or in an oral surgery suite by an oral and maxillofacial surgeon. In either case, the suite is equipped with dental chair and a good source of operating light. The chair provides stability and support and affords the surgeon maximal control of the force being delivered to the patient through the dental forceps. The chair tilts to allow appropriate positioning for maxillary and mandibular tooth extractions. ^[6]

The oral surgery tray is equipped with surgical instruments for soft tissue, such as the following:

• No. 15 scalpel

• Dean scissors

• Needle holder

• Curved hemostat

• Minnesota retractor

• Right-angle Austin retractor

• Weider tongue retractor

• Seldin retractor

• Molt periosteal elevator

• Straight elevator

• Periapical elevators

• Appropriate forceps

• Suction tip

• Adson tissue forceps

• Allis tissue forceps

• Double-ended curette

• Small 3/8 circle reversed cutting needle

• Suture materials

Other instruments included in the tray are for hard tissue, such as the following:

• Blumenthal rongeur forceps

• Bone file

• Burs

• Handpiece

• Hall drill

• Hemostasis materials, such as gelatin tamp and Surgicel

In the past, a chisel and mallet were used to remove bone and split the teeth; currently, however, the use of these instruments is limited to removal of excess bone. Nowadays, we use special surgical burs to remove bone and split the teeth before extraction.

Additional instrument are also included, such as rubber bite blocks and a Molt mouth prop, which are designed to hold the mouth open during extraction.

The key instruments used for extraction are also included in the tray. These may include small and large straight dental elevators (see the image below), left and right triangle-shaped elevators, a Crane pick elevator, a root tip pick, or an apex elevator.

Other important extraction instruments are the various dental forceps designed for extracting maxillary and mandibular teeth. Maxillary instruments include the No. 150 universal forceps, which is designed for extracting premolar and molar maxillary teeth (see the image below), the No. 53 right and left forceps, which are designed specifically for maxillary molars, and the No. 1 maxillary forceps, which is designed for extraction of maxillary incisors and canines.

Instruments designed for extracting mandibular teeth include the No. 151 universal mandibular forceps, the Ash forceps, and the cowhorn forceps (see the images below).

Patient preparation

Patient preparation includes antibacterial mouth rinse before the procedure and adequate anesthesia and appropriate positioning.

Anesthesia

Local anesthesia is required for tooth extraction. It achieves loss of sensation by blocking action potentials and nerve conduction. ^[7] Local anesthesia to the regional sensory nerves supplying the teeth eliminates pain, including that related to temperature and touch, but does not anesthetize the proprioceptive fibers of the involved teeth. For this reason (as well as out of anxiety), patients feel painful pressure during extraction. Consequently, many extractions are performed with local anesthesia along with intravenous (IV) sedation and inhaled nitrous oxide. In cases of severe anxiety of the patient or the need to extract four impacted third molars, the patient is offered the opportunity to undergo the procedure under general anesthesia. Our experience shows an advantage for performing extraction of four impacted third molars under general anesthesia instead of under local anesthesia in 2-4 appointments. There is less postoperative pain, as well as lower stress before and after the procedure. 

Local anesthetic agents commonly used in dentistry belong to either the ester group (eg, procaine) or the amide group (eg, lidocaine). Local anesthetics of the ester group are metabolized by plasma cholinesterase, whereas those of the amide group are metabolized in the liver by microsomal enzymes. Other local anesthetics included in the amide group are mepivacaine and long-acting bupivacaine and articaine.

Several local anesthesia techniques are used in the maxillary and mandibular regions. Maxillary techniques (see the images below) include the following:

• Single tooth - Local infiltration or supraperiosteal injection is achieved for a single tooth by inserting the needle in the mucobuccal fold adjacent to that tooth

• First, second, and third molars - Posterior superior alveolar nerve block anesthetizes the maxillary first, second, and third molars and the buccal mucosa surrounding the teeth; the needle is inserted above the second molar superiorly and medially at a 45º angle to the occlusal plane

• Maxillary nerve block - This is performed via the high maxillary tuberosity approach or through the greater palatine foramen; it anesthetizes all maxillary teeth, the surrounding bone and mucosa, the lower eyelid and nose, and the upper lip ipsilaterally

  Insertion of local anesthesia needle into mucobuccal fold.

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  Supraperiosteal placement of local anesthesia needle.

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  Direction of superior posterior nerve block (arrow).

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  Maxillary division nerve block.

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  Highlighted area is anesthetized by maxillary division nerve block.

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For all maxillary techniques, the palatal infiltration is a necessary local anesthesia for oral surgeries in the maxilla. Anesthesize the incisive nerve for all anterior six teeth or the greater palatine nerve for the premolars and molars.

Mandibular techniques (see the images below) include the following:

• Inferior alveolar nerve block - This anesthetizes all mandibular molars, premolars, canines, and incisors ipsilaterally, including lingual mucosa; the needle is inserted from the opposite side, parallel with the occlusal plane, into the pterygomandibular raphe at the medial side of the mandible toward the mandibular foramen, which is located midway between the external oblique ridge and the posterior ramus

• Long buccal nerve block - This anesthetizes the buccal mucosa ipsilaterally, with the needle inserted into the retromolar region; it is usually given with the inferior alveolar nerve block

• Mental nerve block - This anesthetizes the premolar, canine, and incisor teeth ipsilaterally; the needle is inserted in the mucobuccal fold toward the mental foramen, which is located between and inferior to the 2 premolars

  Highlighted area where injection of inferior alveolar nerve takes place.

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  Direction of needle for inferior alveolar nerve block.

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  Site of needle insertion for long buccal nerve block.

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  Insertion of needle in mucobuccal fold for infiltration of incisor teeth.

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  Highlighted area is anesthetized by local mandibular infiltration.

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As indicated above, local anesthesia alone may not be adequate for an anxious patient who may require additional sedation with inhaled nitrous oxide and oxygen. In the extremely anxious patient, IV sedation with midazolam and opioid analgesia are used.

A study set out to evaluate hemodynamic changes of blood pressure and heart rate on hypertensive patients undergoing tooth extraction using various types of local anesthesia. The study concluded that there is no significant increase of blood pressure with epinephrine and felypressin. Therefore, it is safe to use 2 cartridges of lidocaine 2% with epinephrine 1:80,000 or prilocaine 3% with felypressin 0.03 IU/ml for hypertensive patients whose blood pressure is ≤ 159/99 mm Hg, provided negative aspiration is verified before injection. ^[8]

Positioning

The surgeon and the patient should be positioned in such a way that the patient is comfortable and the surgeon can stand or sit in front of the patient without undue strain. Ideally, the surgical instruments (especially the needle) should be placed out of the patient's sight (usually behind the patient but close to the surgeon).

For mandibular extraction, the positioning is as follows:

• Chair axis - The chair is positioned so that the mandibular occlusal plane is parallel to the floor

• Chair height - The chair is lowered to afford the surgeon the leverage and control needed for the extraction

• Patient head - The patient is asked to turn the head toward the operator

• Operator - The operator is at the 9 o'clock position relative to the patient

• Second hand operator - The second operator is at the 3 o'clock position to help the operator in retracting the cheek, lip, and tongue and stabilizing the jaw

• Assistant - The assistant places the suction tip in one hand and the soft tissue retractor in the other (and also helps with irrigation when needed)

For maxillary extraction, the positioning is as follows:

• Chair axis - The chair is tipped backward so that the maxillary occlusal plane is at an angle of about 60º to the floor

• Chair height - The chair is lowered to the height of the operator's elbow

• Patient head - The patient is asked to lift the head and turn toward the operator for access and visualization

• Operator - The operator is at the 9 o'clock position relative to the patient

• Second hand operator - The second operator stands or sits at the 3 o'clock position and helps with retraction, suctioning, irrigation, and jaw stabilization

Tooth extraction

There are two procedures for tooth extractions: closed extraction and open extraction. The closed technique is also known as the routine technique. The open technique is also known as the surgical technique, or flap technique.

Three fundamental requirements for a good extraction are (1) adequate access and visualization of the field of surgery, (2) an unimpeded pathway for the removal of the tooth, and (3) the use of controlled force to luxate and remove the tooth. 

For proper extraction of a tooth, the operator must release the gingival ligaments and the periodontal ligaments that attach the tooth to the gums and bone. This is done by a special double ended curette and by a luxator. Additionally, an elevator is used for tooth luxation. The suitable forceps  for the extracted tooth is selected in order to enable luxating the tooth from the socket. The elevator and the forceps are located at the cementoenamel junction and apical to that site in order to transfer the force of the extractor to the  tooth roots. Luxation requires apical pressure, buccal force, lingual pressure, rotational pressure, and tractional forces. The operator continues to luxate the tooth with the forceps in a buccolingual direction with slight rotation until the tooth is removed from the socket. ^[9]  

In cases of dilacerated or divergent roots or in cases of a brittle crown due to decay or a large reconstruction, it is recommended to section the tooth according to the number of roots. The upper molar is divided into three parts by a T or Y section, and the lower molar is divided into two parts. For teeth with one circular root, the rotation motion may be used for extraction. Teeth with proximity to the maxillary sinus and the maxillary tuberosity should be extracted after sectioning and extracting each root separately, to reduce the risk of oroantral communication and maxillary tuberosity fracture. 

The role of the opposite hand during extraction

The surgeon's opposite hand plays an active role in the procedure. For the right-handed operator, the left hand has a variety of functions, including the following:

• Reflection of soft tissues of the cheeks, lips, and tongue
• Providing adequate visualization of the area of surgery
• Protecting other teeth from the elevator and forceps
• Helping to stabilize the patient's head during the  process
• Supporting and stabilizing the temporomandibular joint in lower jaw extractions
• Supporting the alveolar process and providing tactile information to the operator concerning the expansion of the alveolar process during the luxation period

The role of the assistant during extraction

To achieve a successful outcome in any surgical procedure, it is useful to have a skilled assistant. The assistant can provide the following services:

• Helping the surgeon visualize and gain access to the operative area by retracting the soft tissue of the cheeks and tongue so that the surgeon can have an unobstructed view of the surgical field
• Retraction of the soft tissue so that the surgeon can apply the instruments to loosen the soft tissue attachment and adapt the forceps to the tooth in the most effective manner
• Suctioning away blood, saliva, and the irrigating solutions used during the surgical procedure
• Helping to achieve proper visualization of the surgical field whenever possible
• Helping to achieve patient comfort, because most patients are unable to tolerate any accumulation of blood or other fluids in their throats 

Tooth extraction can be difficult in older patients with dense supporting bone, dilacerated roots, and broken crowns with extensive caries. Special attention should be paid to adjacent teeth and vital structures (eg, the maxillary sinus, the inferior alveolar nerve, and the lingual and mental nerves). To minimize the risk of pushing the tooth into the maxillary sinus or fracturing the mandible, extensive force should be avoided. ^[10] The best and easiest way of managing tooth extraction complications is to prevent them.

Tooth extraction often leads to root fracture. A small envelope flap can be reflected to expose fractured roots, and a small straight elevator can be used as a shoehorn to luxate broken roots. The buccal beak of the forceps can be used to grasp a portion of the bone at the same time it grasps the root.

The extraction forceps is seated with strong apical pressure to expand the crestal bone around the root and allow root removal. A small root tip can be addressed by placing an endodontic file in the root canal and twisting it with a needle holder. The root can be removed with a No. 4 round bur in a dental handpiece or a small elevator, which displaces the root from its apex.

Teeth that are liable to fracture during extraction are those with large carious lesions, those that have been treated by means of root canal procedures, and those surrounded by dense bone or with ankylosed and dilacerated roots.

Although every effort should be made to remove fractured roots during extraction, there are some circumstances in which these roots are best left in place, as when the root is suspected to be on the verge of entering an anatomic space or when further instrumentation would cause damage to a vital adjacent structure, would result in uncontrolled bleeding, or might necessitate an inordinate amount of bone excision.

Extreme care is required in extracting maxillary teeth close to the maxillary sinus to avoid sinus exposure and subsequent oroantral fistula. Attention is also needed in extracting mandibular teeth close to the inferior alveolar canal and mental foramen to avoid paresthesia. In cases of proximity to the inferior alveolar nerve, as can be observed on a CBCT scan, coronectomy is recomended.

Complications of the procedure

The most common intraoperative complications of tooth extraction are injuries to the soft tissue resulting from lack of attention to the delicate nature of the mucosa and the use of excessive and uncontrolled force during extraction; examples include lip abrasions or burns from a retractor or rotating handpiece.

The next most common complications are injuries to osseous structures, such as fractures of the alveolar plate in the buccal cortex of maxillary canines, molars, and mandibular incisors.

The maxillary tuberosity is often fractured during the extraction of a difficult molar (see the images below), especially a difficult maxillary third molar. ^[11] This complication can be prevented by performing a thorough clinical and radiographic examination and taking care not to apply an excessive amount of uncontrolled force. Fractured bone in the tuberosity can be carefully dissected from the tooth with a straight elevator; the bone and soft tissue can then be sutured in place and the extraction site closed primarily.

Radiographically, the layers of the tooth are easily identifiable because they have different radiopacities. Enamel is the most mineralized of the calcified tissues of the body, and it is the most radiopaque of the 3 tooth layers. Dentin is less radiopaque than enamel and has a radiopacity similar to that of bone. The pulp tissue is not mineralized and appears radiolucent. ^[12] For more information about the relevant anatomy, see Tooth Anatomy.

Extracting a maxillary molar tooth close to the maxillary sinus may result in oroantral communication, which in turn may lead to maxillary sinusitis and the formation of a chronic oroantral fistula.

Intraoperatively, sinus communication can be detected by performing a nose-blowing test to check for passage of air or bubbling of blood in the extraction site. A small communication (< 2 mm) may close on its own with the formation of clot and, subsequently, granulation tissue.

A moderate-sized communication (2-5 mm) necessitates the placement of a figure-eight suture to stabilize the blood clot. Postoperatively, the patient should be instructed to avoid nose-blowing, violent sneezing, and sucking on straws. The patient should be placed on an antibiotic for 7 days, a nasal decongestant for 3 days, and an oral decongestant for 7 days. A larger communication (> 5 mm) necessitates a flap procedure to close the defect.

Even with meticulous surgical technique, tooth extraction may result in injury to adjacent vital structures. Lingual nerve paresthesia may result after injection if the needle passes through the nerve, the distal incision is positioned too far lingually, or the nerve is cut during lingual bone removal. The recommended method to prevent this complication is to elevate a full lingual flap and retract it by a lingual retractor during tooth sectioning. 

Mandibular fracture following third molar extraction is rare (see the image below). A meta-analysis found that this iatrogenic occurrence is multifactorial. The incidence is higher in the fifth decade of life, and the prevalence is greater among males. Risk factors are the removal of the third molar in a fully dentate patient, teeth with associated pathology, and an impacted tooth, mainly in the angle region and usually in the left quadrant. Mandibular fracture occurs more frequently during the time interval of 3 weeks postoperatively. ^[13]

Coronectomy is considered in cases in which there is an intimate relationship between the roots of a retained lower third molar (occasionally second or first molars) and the inferior alveolar nerve, in the absence of contraindications. The decision to use this technique is made with the aid of CBCT scans. The short- to medium-term success rate is excellent. ^[14]

Indications

The following are indications for coronectomy:

• A moderate or high risk of damage to the inferior alveolar nerve if the tooth is removed completely, as assessed by a Panorex-type radiograph supplemented by CBCT scanning
• An impacted third molar with tooth roots that are in proximity to the inferior alveolar nerve

Contraindications

Coronectomy is contraindicated in the following settings:

• A tooth lying horizontally along the path of the inferior alveolar nerve 
• Cases in which it is impossible to remove all the enamel of the tooth; enamel retention is associated with a much higher failure rate
• Infection involving the roots of the teeth
• Caries involving the roots of the teeth
• Cases in which the second molars are to be distalized orthodontically

If the roots are mobilized during the procedure, they should be removed.

Surgical technique

The technique involves total sectioning of the crown of the tooth, removal of all enamel, and removal of enough of the coronal portion of the tooth such that the portion to be retained is at least 2-3 mm below the alveolar crest of bone.

The technique involves raising buccal and small lingual flaps and the placement of a lingual retractor to protect the lingual nerve and lingual soft tissues so that the crown of the tooth can be sectioned with a 702-type fissure bur through the whole crown of the tooth.

Following the crown sectioning, the crown is removed gently and the enamel rests are removed by a diamond round bur with continuous irrigation.

Antibiotic treatment

Antibiotics should be given prophylactically so that they are in the pulp chamber of the tooth to be sectioned at the time of removal. This means giving them perioperatively before and after the procedure.

Suturing

It is preferable to close the socket primarily by undermining and releasing the periosteum if necessary, to obtain a tension-free, water-tight, primary closure of the socket. 

Complications

The following are potential complications of coronectomy:

• Roots that must be removed during the operation owing to mobility
• Infection and pain
• Tissue pocketing in the nearby tooth
• Root migration superiorly, which necessitates a second operation to remove the tooth