Mandibular fracture is a pathological condition that occurs when the integrity of the mandibular bone is violated. Patients complain of the appearance of painful swelling in the area of damage, an increase in pain when chewing, opening the mouth. The bite is broken, ruptures of the mucous membrane with the exposure of the bone edge are detected in the oral cavity. The teeth on the damaged fragment are movable. The diagnosis of “mandibular fracture” is made based on complaints, local status, radiography data. The primary treatment is to eliminate pain, antiseptic treatment of the wound, temporary splinting. Permanent fixation of fragments is achieved conservatively or surgically.
S02.6 Mandibular fracture
Mandibular fracture is a bone injury accompanied by a complete or partial violation of its integrity. Among maxillofacial region injuries, fractures of the lower jaw are diagnosed most often. Combined injuries of the maxillary bone and mandible are detected in 15% of the examined. The main group of patients are men aged 20 to 40 years. In children, fractures of the lower jaw occur in 15% of cases.
In terms of prevalence, the first position is occupied by body fractures (over 65%), in second place – angle injuries (37%), in third – branch fractures. Violation of the integrity of the mental department is diagnosed in every twentieth patient. The ratio of unilateral and bilateral injuries of the mandibular bone is 1:1. About a quarter of patients need surgical treatment of a mandibular fracture.
Mandibular fracture occurs due to the impact of a force whose magnitude exceeds the plastic characteristics of the bone tissue, which happens, for example, as a result of frontal and lateral blows to the lower third of the jaw, when falling from a height on the face of heavy objects, in the event of an accident. The localization of the fracture line corresponds to a bone section with reduced density. The angle of the lower jaw, the condyle and articular processes, and the chin are more susceptible to traumatic injuries.
In dentistry, there are also pathological fractures of the lower jaw that occur as a result of the application of forces that do not exceed physiological ones. Similar injuries are observed in resorptive processes of bone tissue in patients with inflammatory and destructive (osteomyelitis, radicular cysts) diseases or in the case of the development of a malignant tumor.
Fractures of the lower jaw are not only direct, but also reflected. With a direct fracture, the integrity of the bone is violated at the point of impact of the traumatic force. Localization of reflected fractures of the lower jaw directly depends on the area and direction of impact. With bilateral compression of the mandibular bone in the area of the molars, the maximum tension of the bone tissue is concentrated in the area of the median line. When a high-amplitude force is directly applied to the chin area, the necks of the lower jaw are the most vulnerable. Unilateral fracture of the neck is often reflected, occurs due to a side impact. Dislocation of fragments in a mandibular fracture is determined by the trajectory of the impact of the traumatic force, the area of the damaged area, the group of muscles attached to its surface.
According to localization , fractures of the lower jaw are divided into 2 groups:
- Fractures of the body. They are more often open, clinically accompanied by rupture of the mucous membrane, bleeding. There are median (the fault line runs between the central incisors), mental (a violation of integrity is observed in the area between the canine and premolar or between premolars), lateral (the damage zone is localized in the molar region), angular (the bone is damaged in the angle area) fractures of the lower jaw.
- Branch fractures. This category includes violations of the integrity of the branch of the mandibular bone (the fracture line at the same time has a parallel or perpendicular direction relative to the longitudinal axis) and its two processes – articular and coronal. In turn, a fracture of the articular process can take place at the level of the base, neck or head. Closed fractures of the mandibular bone branch are more often diagnosed.
Fractures of the mandible are also divided into linear (one fracture line is observed), comminuted (several fragments are formed that intersect at different angles) and combined, open and closed, unilateral and bilateral.
With a mandibular fracture, patients complain of the appearance of painful swelling in the area of damage. Unpleasant sensations increase when chewing, biting off food. In case of violation of the integrity of large blood vessels, bleeding occurs. With a lateral linear mandibular fracture, the face acquires an asymmetric configuration. Traumatic damage to the mandibular nerve causes numbness of the mental zone and the lower lip. The skin color is changed due to the formation of bruises, hematomas.
With open fractures on the mucous membrane, ruptures with the exposure of the bone edge are detected. Hemorrhages are determined by the transitional fold. Articulation with a mandibular fracture is impaired. The nature of the teeth closing is determined by the level, symmetry of the damage. Patients have a stepped dentition. The fissure-tubercle contact is broken. Teeth located in the fracture line are mobile (2-3 degrees). Complete dislocations of teeth are often detected.
The diagnosis of mandibular fracture is made on the basis of patient complaints, local status, radiography data. During a physical examination, a dentist reveals characteristic external signs of a mandibular fracture: swelling of soft tissues in the area of damage, discoloration and violation of the integrity of the skin. There is a deviation of the median line. With palpatory examination, it is possible to detect irregularities, bone entanglements. If the fracture line of the lower jaw passes in the area of the angle or branch, slight pressure on the chin leads to increased soreness at the site of injury. And, conversely, if the patient has a mental fracture, bilateral pressure in the angular areas causes the appearance of pronounced pain in the frontal zone.
To determine the localization of the mandibular fracture, dentists use a diagnostic test, in which a spatula is placed on the transversal on the chewing surfaces of the lower molars. Light tapping on the protruding part of the spatula with closed dentition causes pain in the patient in the place where the fracture line of the lower jaw passes. To diagnose the integrity of the articular process, the skin area in front of the tragus is palpated. In order to determine the trajectory of movement of the articular head, a test is used, in which the dentist puts his index fingers into the auditory passages of the victim. At the same time, the patient slowly performs movements in the vertical and transversal planes. The absence of movements of the articular head confirms the presence of damage to the condyle process.
Radiography data are of key importance in the process of diagnosing a mandibular fracture. Often, several images are taken in different projections (anterior, lateral radiographs). If a mental mandibular fracture is suspected, along with an overview radiography, a sighting radiograph is made. To determine the integrity of the condyle process, special styling is used (according to Schueller, Parma). On the radiograph, when the lower jaw is fractured, a violation of the integrity of the bone is detected in the form of a thin strip of enlightenment. It is necessary to differentiate with other injuries of the bones of the maxillofacial region, as well as with bruises of soft tissues. A physical examination is performed by a maxillofacial surgeon.
Treatment of mandibular fracture includes antiseptic wound treatment, elimination of pain syndrome. To achieve stable reposition and fixation of fragments, the edges of the bone are smoothed, the interposition of soft tissues between fragments is eliminated. Teeth located on the fracture line are subject to removal. In order to prevent the attachment of a secondary infection, the mucosa in the rupture area is sutured.
The primary immobilization in case of a mandibular fracture consists in creating a fixed block consisting of the mandible pressed against the maxillary bones. To do this, use bandages or the method of inter-jaw ligature connection. In case of linear fractures of the jaw body without displacement, as well as in the case of angular fractures of the lower jaw without displacement, double-jaw wire splinting of the jaw is used to fix and immobilize fragments.
Due to the low efficiency of manual reposition of fragments in angular and condyle fractures of the mandible with displacement, surgical treatment is more often used. Among the main techniques of open osteosynthesis, bone suture, mini-plates, polyamide thread are used. To connect the fragments with a bone suture, soft tissue incisions are made, the bone is skeletonized from the buccal and oral sides. Fragments are removed from the fracture line of the lower jaw, the edges of the bone are smoothed. Holes are made in the fragments on both sides of the damage line to fix the wire. After laying the muco-periosteal flap, the wound is sutured. To achieve a more rigid immobilization in case of mandibular fracture, dental splints are additionally used.
Mini-plates are shown for oblique, comminuted fractures of the branch and body of the lower jaw. The incision is made only from the buccal side, after separation of the muco-periosteal flap, the fracture is treated. Holes are drilled on the fragments on both sides of the fracture line of the lower jaw, mini-plates are fixed with screws. The muco-periosteal flap is put in place, stitches are applied.
To prevent the development of post-traumatic osteomyelitis, patients are prescribed antibacterial drugs. The effectiveness of treatment of fractures of the lower jaw depends on the timeliness of specialized care, the nature of the fracture, the presence of complications. The primary bone callus with mandibular fracture is formed within 20 days, the secondary – for 6-8 weeks. With early treatment of a patient with a body fracture, the prognosis is favorable. Damage to the branch and its processes can lead to persistent functional disorders.