Mandibular Alveolar Fractures 

Updated: Sep 26, 2018
Author: William D Clark, MD, DDS; Chief Editor: Arlen D Meyers, MD, MBA 

Overview

Background

Fractures of the alveolar process of the mandible are uncommon. Unfortunately, their treatment is often fraught with problems, and uninitiated surgeons tend to underestimate these types of fractures and their problems.

History of the Procedure

Mandible fractures are described in early Egyptian writings. Hippocrates advocated the use of bandages and interdental wiring for the treatment of mandibular fractures. In a 3-part article published during the Civil War, Gunning wrote of using dental splints attached to elaborate external appliances. In 1881, Gilmer first described the use of bars on both arches, fixed to the teeth and each other with fine wire ligatures.

Schede is credited for the first mandibular bone plating. He is said to have used a steel plate screwed to the mandible in the late 1880s. In 1934, Vorschutz described external fixation using transdermal bone screws and plaster. The Morris biphase is a refinement of that technique.

The history of rigid internal fixation devices is ongoing; a new theory and a corresponding set of devices appear every few years.

Clark's classes of alveolar fractures are depicted below.

The various classes of alveolar fractures (per Cla The various classes of alveolar fractures (per Clark).

Problem

Simply stated, the approach to treating these injuries is to do what is necessary to reduce them and then do what is necessary to hold them in reduction until they are healed.[1] The treatment options are somewhat limited by the lack of room for drill holes and associated hardware when the fracture involves a dentulous segment. Even with an edentulous segment, hardware is rarely practical because it usually ends up under a dental prosthesis and cannot be tolerated.

Epidemiology

Frequency

As pertains to the prevalence of facial fractures in the United States, the mandible is second only to the nose. Fractures of the alveolus account for only 1-5% of all mandibular fractures, making the alveolus one of the least commonly fractured regions.

The major difference in mandible fractures in countries other than the United States is in the etiology of these fractures. Some locations have less vehicular trauma because of a relative lack of vehicular transportation. Interpersonal facial trauma tends to have lower energy than vehicular trauma and, therefore, generally results in less severe injuries. Most countries other than the United States have fewer incidents concerning civilian firearms and a correspondingly lower frequency of penetrating trauma.

Etiology

Alveolar process fractures are the result of blunt or penetrating trauma. The 2 most common etiologies of such blunt trauma in adults are fist fights and motor vehicle accidents. Other sources of facial trauma include athletic injuries, falls, and industrial accidents.[2]

Penetrating trauma to the mandible is most commonly in the form of a gunshot wound.

A retrospective study by Marotti et al found that in patients with isolated alveolar process fracture with associated trauma to the permanent teeth, pulp necrosis was the most frequent tooth complication, being found in over 40% of the traumatized teeth. The investigators reported that mature root development and concomitant injury were significant risk factors for pulp necrosis.[3]

A study by Lauridsen et al reported that for teeth with mature root development that have been involved in an alveolar process fracture, risk factors for pulp necrosis include fracture in relation to the apex, a greater than 2 mm displacement in the horizontal portion of the fracture, incomplete repositioning, and patient age above 30 years.[4]

Pathophysiology

For blunt trauma to produce an isolated fracture of the alveolar process, the blow must be concentrated on a segment of the alveolar process; however, this is an uncommon event. Alveolar process fractures that share fracture lines with other mandibular fractures are more common, usually representing a comminution of a body of mandible fractures.

Presentation

The usual presenting reports with any fracture of the mandible as a result of trauma are localized tenderness, swelling, and malocclusion.

Indications

The presence of an alveolar fracture is the indication for treatment. The mode of treatment varies among patients.

Relevant Anatomy

A dental alveolus is a tooth socket. The alveolar process of the mandible is defined as the portion of the mandible surrounding and supporting the teeth. After loss of teeth, the associated alveolar process undergoes atrophy. Cortical bone covers the exposed surface of the alveolar process and the underlying cancellous bone; tooth sockets and teeth fill the remainder of the process. Tooth sockets are lined with thin, compact bone that is penetrated by blood vessels, lymphatics, and nerves. This alveolar bone contains the embedded ends of the connective-tissue fibers of the periodontal membrane (ie, Sharpey fibers).

Contraindications

Few contraindications exist to treating alveolar fractures. A nondisplaced class I fracture requires only observation. With other alveolar fractures, the patient's general condition may prohibit definitive treatment; examples include a chronic medical condition or results of trauma sustained when the mandibular fracture occurred. Head trauma resulting in an altered state of consciousness is the most common contraindication encountered in patients with alveolar fractures. Suspected or proven cervical spine injuries are also common contraindications. Most of these contraindications resolve with time and treatment. Hopefully, the alveolar process fracture can still be treated once the patient's general condition permits.

 

Workup

Laboratory Studies

No lab studies are required to evaluate a fracture of the alveolar process of the mandible. Associated injuries are common and may require such studies.

Imaging Studies

See the list below:

  • CT has become the criterion standard for evaluating the mandible for fractures. In patients with multiple traumas, many emergency departments obtain near whole-body CT scans so that the needed information is available.

  • The panoramic dental radiograph was long the criterion standard for evaluating the mandible and is still an excellent alternative to and/or adjunct to CT. It does offer the advantage of better evaluating the teeth for injuries.

  • When the needed equipment is not available or the patient cannot be placed in the apparatus, plain radiographs of the mandible may be sufficient.

  • Periapical dental radiographs are often helpful in providing precise information about the status of teeth within a fractured segment of the alveolar process. Dental consultation is usually required to obtain these radiographs.

 

Treatment

Medical Therapy

Medical therapies for alveolar process fractures are for patient comfort and to prevent complications, namely infection.

Mild-to-moderate analgesics may be required, taking into consideration any associated injuries that may contraindicate their use or limit their dose. Acetaminophen in liquid or tablet form may be sufficient. For an isolated alveolar process fracture, nothing stronger than acetaminophen with codeine should be required. Requests for stronger analgesia should prompt the treating surgeon to consider unrecognized injuries, complications, or substance abuse.

Antibiotic therapy reduces the prevalence of infections with mandibular fractures. Penicillin, prescribed at the appropriate dose for age, is an excellent choice. For the patient who is allergic to penicillin, clindamycin is a good alternative.

Surgical Therapy

Reduction and immobilization of the fracture is mandated for alveolar process fractures.[5] The specific approach depends on the specifics of the injury. Previously, no classification of these fractures has been available to guide decision making. The authors offer the following classification:

  • Class I fracture of the alveolar process: This involves a fracture of the edentulous segment.

  • Class II fracture of the alveolar process: The fracture involves dentulous segment with little, if any, displacement.

  • Class III fracture of the alveolar process: The fracture involves dentulous segment with moderate-to-severe displacement.

  • Class IV fracture of the alveolar process: The alveolar process fracture shares one or more fracture lines with other fractures of the tooth-bearing facial skeleton.

  • Class I to IV fractures are depicted in the image below.

    The various classes of alveolar fractures (per Cla The various classes of alveolar fractures (per Clark).

Preoperative Details

A medically stable patient with a mandible fracture should receive definitive care as soon as is practical. Numerous studies have demonstrated that delays in treatment increase the complication rate and reduce the chance of obtaining the best surgical result. The prerequisites for definitive care of these injuries are imaging studies sufficient to evaluate the injuries, a stable patient, an evaluation by the anesthetist, and informed consent. The anesthesia team must be informed that nasal intubation is required.

Dental considerations exist when an alveolar process fracture involves a dentulous segment. Teeth within an alveolar segment may be fractured, especially the root portion and most especially the root tip. Imaging studies may not show dental fractures; therefore, careful inspection of the teeth, the intact portion of the mandible, and alveolar fragments is required. The usual recommendation for a tooth fracture involving the root is dental consultation or, if not practical, extraction. The consulting dentist performs an immediate root canal treatment, extracts the tooth and its fragments, or takes responsibility for long-term management.

Fractures of tooth crowns are not unique to alveolar fractures and are not covered in this article.

When the apical portions of the tooth roots are completely separated from their blood supply, the affected teeth are at risk of becoming devitalized and eventually producing periapical abscesses. This is a common finding in class III alveolar fractures. When practical, consult a dentist to consider urgent root canal therapy to save these teeth and help prevent complications. When a dental consultation is not practical, the treating surgeon must use his or her judgment relative to each tooth in a displaced alveolar segment. The options are extraction versus retention and later dental consultation. Since the involved teeth may survive, the authors prefer to conserve teeth that appear to be otherwise healthy. Periodontitis, as manifested by tooth mobility and periodontal pockets, should move one toward extraction, as should evidence of periapical pathology.

When a splint is going to be used to stabilize a fractured alveolar segment, it needs to be fabricated during the preoperative period. Impressions of the dental arches are required and are used to make plaster models. Model surgery restores the normal anatomic relationships of the fractured segments and allows accurate splints to be fabricated.

Intraoperative Details

The patient is placed in the supine position and is nasally intubated by the anesthesia team. The surgical team usually finds that headlights offer the best illumination. Surgical treatment of mandibular fractures often includes the use of sharp objects (eg, wire, screws, arch bars); therefore, attention to detail is necessary to minimize the risk of glove puncture.

True sterile preparation of the operative site for repair of mandible fractures is not possible. The extent of preparation to create a clean, disinfected field is controversial. Some clean the teeth, gingivae, and alveolar mucosae with a toothbrush and 3% hydrogen peroxide. The face is painted with povidone iodine solution. If a skin incision is required for an open reduction of another fracture, a typical povidone iodine soap scrub preparation is performed.

Preoperative examinations are often impaired by tenderness and masticatory muscle spasm; therefore, a thorough reexamination of the face and oral cavity is performed before definitive therapy. The entire mandible is carefully inspected and palpated. All teeth are inspected and evaluated for injury and mobility. A survey of the dental arches is completed to detect any sockets missing teeth. The maxilla is examined to detect any previously missed injuries. For class I fractures, adequate treatment is usually as simple as digital molding of bony fragments and closing any overlaying mucosal/gingival lacerations.

Class II fractures that need reduction may require a great deal of force to move into anatomic position. Posterior fragments are almost always displaced to the lingual area. Producing the needed facially directed forces by manual means can be difficult. Large, heavy forceps, such as those used for dental extractions, may prove useful to apply reducing forces on the bony fragment. Reduced fragments may be held in place by maxillomandibular fixation (MMF) or overlay splints.

Class III fractures typically offer the most challenges. Reducing the displaced segment of the alveolar process can be surprisingly difficult. This is believed to be because the encompassing portion of the mandible is intact, and one must overcome the resistance produced by the interaction of the small irregularities of the bony surfaces. In other words, the space into which the fragment must be placed has no give. Occasionally, removing some of the bony irregularities of the fragment and/or the receiving space in the intact portion of the mandible may be necessary. This is usually best accomplished by use of a power drill with a suitable size bur or a fine rhinoplasty rasp. In any case, bone removal should be limited to that which is essential to accomplish the goal.

Holding class III fractures in their anatomic position can also be a challenge. The general rule of facial fractures, which is that fractures that are more difficult to reduce result in more stable reductions, is less true for these fractures than for most others. Techniques to maintain reduction of these fractures include arch bars, various forms of MMF, and various splints.

Class IV fractures are usually less challenging than class III fractures because the treatment of associated fractures usually gives excellent exposure; usually no physical barrier exists to reduction, and treatment of the associated fractures often accomplishes treatment for the alveolar process portion of the injury. When this is not the case, the use of techniques described for class III fractures is in order.

Once alveolar segments have been reduced, they need to be stabilized until healing has occurred.

One mode of stabilizing an alveolar segment is the use of an acid-etch wire composite splint. This device uses a heavy stainless steel wire fixed to the teeth within the segment and several teeth on either side. Attachment to the teeth is accomplished by use of a composite dental restorative material that adheres to both the wire and to the acid-etched dental enamel. The major limiting factor of using this material is that a dentist is required.

When arch bars are used for stabilization of fragments, each sound tooth in the mandible is ligated to the arch bar with fine wire ligatures after the segments have been anatomically reduced.

When splints are used to stabilize fractures, they may be ligated to sound teeth and may be further secured by 3-point circummandibular wiring.

Postoperative Details

Analgesics and antibiotics are indicated postoperatively. Analgesics are usually required for several days. Administration of antibiotics for 7-10 days postoperatively should provide good infection prevention, although a study by Schaller et al found that in patients who underwent surgery for mandibular fractures involving the alveolus, the incidence of infection at 6-month follow-up did not differ significantly between those who received a 1-day postoperative course of antibiotics (29 patients) and those who received a 5-day course (30 patients).[6]

If MMF is used, precautions to help prevent and/or address nausea and vomiting are paramount. The nursing staff needs specific instructions on measures to take with patients who are nauseous or in whom vomiting is impending. Some use antiemetics prophylactically. Others order antiemetics be given at the first hint of nausea. If the MMF technique includes having wires hold the teeth in occlusion, a wire-cutting device should be with the patient for the first day. Many place the wire cutters on a tracheostomy tape around the patient's neck.

Follow-up

After discharge from the hospital, the patient should be seen weekly and as needed. Weekly examinations should assess nutritional status, wound healing, oral hygiene, maintenance of occlusion, and signs of infection.

For patient education resources, see the Breaks, Fractures, and Dislocations Center and Teeth and Mouth Center, as well as Broken Jaw and Broken or Knocked-out Teeth.

Complications

Malunion and malocclusion

Malunion and malocclusion are the most common major complications. They result from inadequate reduction and/or loss of reduction during the healing process.

Infection

Infection is usually localized and typically responds to antibiotics. Collections of pus should be drained. If present, hardware may require removal.

Exposure of implanted hardware

This complication is uncommon because hardware is rarely used for these fractures. However, if this complication occurs, it requires removal of hardware.

Nonunion

Nonunion is an uncommon complication. It requires that the fracture lines be exposed and freshened with reapplication of fixation. Nonunion may require a bone graft in extreme cases.

Outcome and Prognosis

A successful outcome is achieved when the fragment is healed in the anatomic position and the teeth are in normal occlusion, display normal mobility in their sockets, and are viable.

Future and Controversies

Treatment of alveolar process fractures is essentially free of controversy. Since plating systems are rarely practical for these injuries, associated controversies are avoided.

Future advances in this area may be related to refinements in the use of orthodontic techniques in the stabilization of the alveolar segments.

 

Medication

Medication Summary

The goals of pharmacotherapy are to reduce morbidity and prevent complications.

Analgesics

Class Summary

Pain control is essential to quality patient care. Analgesics ensure patient comfort, promote pulmonary toilet, and have sedating properties beneficial to patients who experience pain.

Acetaminophen (Acephen, Cetafen, Little Fevers, Mapap, Tylenol, Q-Pap, Valorin)

This agent may inhibit prostaglandin synthesis in the central nervous system (CNS) and operate peripherally to block the generation of pain impulses.

Codeine/acetaminophen (Tylenol with Codeine #3, Tylenol with Codeine #4, Capital/Codeine)

This combination is used for the relief of moderate to severe pain. By binding to opioid receptors in the CNS, codeine inhibits ascending pain pathways, altering the perception and response to pain. Acetaminophen may operate peripherally to block the generation of pain impulses.

Antibiotics

Class Summary

Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting.

Penicillin G aqueous (Pfizerpen-G)

Penicillin G interferes with the synthesis of cell wall mucopeptide during active multiplication, resulting in bactericidal activity against susceptible microorganisms.

Clindamycin (Cleocin)

This agent is a semisynthetic antibiotic produced by 7(S)-chloro-substitution of the 7(R)-hydroxyl group of the parent compound, lincomycin. Clindamycin is a bacterial growth inhibitor; it may block the dissociation of peptidyl transfer ribonucleic acid (tRNA) from ribosomes, halting the synthesis of RNA-dependent protein. The drug does not penetrate the CNS, despite being widely distributed in the body. Protein bound, clindamycin is excreted by the liver and kidneys.

Amoxicillin (Moxatag)

Amoxicillin is often used in place of penicillin, but it has not been demonstrated to be more effective. The drug binds to penicillin-binding proteins, inhibiting bacterial cell wall growth.