What Is a Jaw Reduction?

Mandibular retraction is a malocclusion of mandibular retreat caused by mandibular hypoplasia or congenital lack of lower anterior teeth and pterygoid dysfunction. Mandibular retraction malformations are not common and can often be confused with maxillary anterior process deformities. The appearance of the mandibular deformity is mainly short in the mandibular condyle, 1/3 below the face, and looks like a "bird's beak" on the side. Seriously affect the appearance and mental health. Correction must be done in different ways depending on the patient's age. Orthodontic treatment is available for patients in the growth phase, and orthognathic surgery is available for adult patients.

Basic Information

English name

mandibular retrusion

English alias

mandibular retrognathism

Visiting department

Stomatology

Common symptoms

The anterior teeth are deeply covered, the upper anterior teeth are obviously inclined and exposed outside the mouth

Clinical manifestations of mandibular retraction

1. The lower jaw is retracted, the upper jaw is basically normal, the front teeth are deeply covered, and the upper front teeth are obviously inclined. Face, posterior teeth occlusal relationship is distant-medium relationship.

2. The lower jaw is retracted, and the anterior teeth are deep overbite. The upper front teeth bite on the gingival side of the lower front teeth, and the lower front teeth bite on the epicondylus mucosa. The posterior teeth bite relationship is far-to-middle relationship.

3. The lower jaw is retracted, the lower dental arch is smaller than the upper dental arch, the height of the lower 1/3 of the face becomes shorter, and the lower jaw is more retracted from the side view.

4. For those with deep upper anterior teeth, the upper anterior teeth are exposed outside the mouth.

Mandibular retraction

This disease should be checked by A-line cephalometric film.

Mandibular retraction diagnosis

1. The oral model of mandibular retraction is similar to that of the maxillary forward process. Deep anterior teeth are often accompanied by deep overbite. The difference is that the position of the maxilla is normal and the mandibular condyle is retracted.

2. X-ray head shadow measurement shows that the SNB angle and the face angle are smaller than the normal range. The ANB angle is greater than normal, and the SNA angle is normal.

Mandibular Retraction Treatment

1. Functional mandibular retraction therapy: Wear a maxillary active appliance with a planar guide, and try to remove individual interdental interferences as much as possible, and do exercises for external pterygoid muscle function. The neutral occlusion habit has been basically completed, then the planar guide Change the beveled guide. After the back teeth come into contact, continue to wear the beveled guide for a period of time. You can also wear non-functional flat occlusal pad-type up-and-down orthopedics, and perform inter-maxillary traction to improve the relationship between the upper and lower jaws. .

2. If the maxillary dental arch is narrow and the mandible is retracted, use a planar guide and an expander spring to adjust the force to enlarge the upper dental arch. After the occlusion is balanced, the inclined jaw can be used to guide the lower jaw forward to the normal position. Fixed appliance.

3. The mandible is retracted, and the posterior teeth are neutral. The anterior teeth of the mandible are pushed to the lip side to open the gap and set the teeth.

4. Severe mandibular retraction can be corrected with orthognathic surgery, and for palatoplasty.

5. Mandibular retraction and maxillary protrusion, the deepest coverage of this type of dental and maxillary deformities, orthognathic surgery must be based, followed by orthodontic treatment.

6. For those who need surgery, conventional anti-infective treatment can be used.