What Is the Mandible?

The mandible is located in the lower part of the face and is arched. It forms the anterior wall and side wall of the oral cavity.

The mandible is located in the lower part of the face and is arched. It forms the anterior wall and side wall of the oral cavity.

Chinese name

lower jaw

Foreign name

Mandible

Classification

Body and Ascending Branch

Subject

biology

Mandible I. Anatomy and related tissues

Its horizontal part is the mandibular body, its vertical part is the mandibular branch, the surface layer is bone dense, and the inner part is cancellous. The mandibular body is divided into two sides, the inner and outer sides, and the upper and lower edges. The mandibular branch is divided into two sides, four margins and two processes. The mandibular branch forms a joint with the temporal bone. The joint is very flexible, and can perform a variety of actions, including chewing. The trabeculae of the jawbone are also aligned with the direction of the chewing muscle's tensile force and force transmission. With . It transmitted force through the mandibular branch and finally the coracoid process, but a part of the force was also transmitted to the skull base through this. The trabeculae in the anterior part of the mandible, from the lower edge of one side to the upper edge of the opposite side, and the trabeculae on both sides intersect at the joint of the mandible. Due to the influence of the muscle force line and the diaphragm force line, the structural form of the mandible also changes functionally. Although the mandible has a large area and volume in the maxillofacial bone, there are several weak links in the structure. The condylar neck, mandibular angle, sacral foramen, and median joint of the jawbone are the sites of fracture.

The bone of the mandible is dense and the blood supply is poor. In addition to the main alveolar artery blood supply, it also receives blood from the mucosal artery branch of the bone surface.

Mandible II. Related diseases and treatment

In recent years, maxillofacial fractures have been increasing year by year, the degree of injury has become increasingly serious, and the injuries have become increasingly complex. The mandible is located in the exposed part of the human body, and the incidence of fractures is the highest in the maxillofacial fractures. According to literature statistics, the incidence of mandibular fractures accounts for about 25% to 28% of maxillofacial injuries and 55% to 72% of maxillofacial fractures. Mandibular fractures are more common in young men, most of which are the crotch, and there are more fractures in the middle face. Most of them are caused by car accidents in recent years. Strong internal fixation is a good treatment.

1 Mandible 1, surgical approach

The choice of surgical approach for mandibular fractures is mainly based on the location and nature of the fracture line. The principle is to make the wound as concealed as possible on the basis of easy operation and to minimize surgical trauma. Mandibular fracture surgical approaches mainly include: extraoral approach, intraoral approach, combined intra-oral approach, and trans-wound approach. The choice of surgical approach for mandibular fractures is not static or even fixed and formatted. It should be comprehensively considered according to the specific injury of the patient and the aesthetic requirements of the patient.

2 Mandible 2. Fixation method

A. Intermaxillary fixation: Intermaxillary fixation (IMF) is a method that fixes the upper and lower dentitions through dental arch splints or elastic traction to achieve the reduction and fixation of the fracture. The main purpose is to fix the fractured segment To restore the patient's occlusal relationship.

B. Strong internal fixation. Since the 1960s, research on rigid internal fixatino (RIF) systems for mandibular fractures has been carried out abroad. After decades of clinical application, it has been proven that RIF technology is the best method for mandibular fractures and has become the mainstream of mandibular fracture fixation. Because RFI can meet the biomechanical requirements of the mandible, effective three-dimensional stability changes the environment of the fracture area, so that local blood flow is quickly restored, and the fracture area is directly ossified and connected to accelerate fracture healing. RFI is suitable for mandibular fractures in any part. Whether the fracture is open, closed, infected or uninfected, it can achieve a good effect, which has unparalleled advantages over conservative treatment. The RIF series of mandibular fractures includes small or universal bone plates, tension screws, power compression bone plates and centrifugal power compression bone plates, self-locking bone plates and absorbable bone plate systems. There are mainly small or universal bone plate system tension screw system power compression bone plate and centrifugal power compression bone plate system self-locking plate (nail) internal fixation absorbable internal fixation system

C. Biological fixation: The idea is to use internal fixation that protects blood flow during the treatment of mandibular fractures, and to reduce as far as possible from the fracture site. Anatomic reduction of the fracture segment is not required, thereby maximizing the protection of the periosteal fracture site Attached to the soft tissue, it also uses a low elastic modulus internal fixation and reduces the contact area between the fixation and the bone cortex, providing a normal physiological environment for fracture healing.

3 Mandible 3. Common postoperative complications:

Infection Disorder of occlusal relationship and occlusal interference Facial nerve injury Root injury Affect jaw development Fracture of bone plate Exposure of bone plate Loose and loose screws