Broken lower jaw

2021-02-02 12:00 AM

Bruising gums + bottom of the hallway and floor of the mouth. May tear the gum lining. The teeth where the broken road passed was wide and wobbly. Possible Broken or missing teeth. Little wrong joints.

Anatomical features of the lower jaw

The lower jaw bone is a moving, flattened, solid, spongy inner bone with a lower teeth canal resembling a trough, outside with a chin hole.

The lower jaw bone only relies on the bridge protrusion and the small spherical neck.

Therefore, the lower jaw bone has a number of weak positions: the incisors, chin holes, jaw angle and spherical neck.

The lower jaw bone has a lot of attachment muscles (the muscles that lift and lower the jaw), so when broken, it is easy to move due to the stretching muscles.

When the nerve of the lower teeth has been ruptured, anesthesia for the chin: the sign of VINCENT


Partial fracture

Tooth drive fracture

Common in the incisors.

Upper molar fracture is more common than lower jaw bone.

When broken, the bone fragment is usually folded inward, pulling the tooth

Treatment: depending on the specific condition, it can be removed or fixed to adjacent healthy teeth with steel braces or self-hardening plastic.

Fracture of part of the bridge bulge or chord underneath the jawbone

Usually left alone.

Broken parrot's muzzle

Pure parrot snout fracture is very rare.

May be seen with bridge convex fracture + split fracture cheekbone.

If the conure fracture does not affect chewing + open mouth: No treatment needed.

If after fixation but still affect function: need surgery to remove the conure.

Perforation through the bone

Usually due to a sharp, small cross-section, high speed (eg a bullet)

Treatment: Usually not. If there is a probe later: Cut the probe + remove the entire inflammatory organization.

Total fracture (loss of bone continuity)      

Broken one

Middle fracture.

Broken side.

Broken jaw angle.

Broken branches high.

Broken bridge convex.

Two-way broken

Symmetry: fracture of the jaw angle or two spherical neck fracture.

Asymmetry: middle / middle / lateral fracture coordinated with other fracture at other location.

Example: fracture angle of one jaw + spherical neck on the other side.

Three-way broken

Center fracture / middle edge + fracture of jaw angle / 2 spherical neck or other forms in any position.

Break into pieces

Common in war (fire gas), difficult to describe.

The influence of the direction of trauma

Direction of force from front to back

Center fracture / middle edge fracture.

Break one or both of the jaw angles.

Broken one or both of the spherical neck.

Broken combination of the above lines.

Side force direction

Fractures at the touch points in transverse branches / jaw angles / spherical neck.

Fracture in the middle: due to the squeezing curve.

Fracture on the opposite side of a horizontal branch or a broken spherical neck due to the force of rotation around a bridge bulge

Broken combination of the above.

1 Broken line at touch point + 1 broken line at the other side of the bridge.

1 fracture line in the middle + 1 fracture line in a convex neck on the same side.

Clinical symptoms

Middle fracture (middle and middle edge fracture)

The broken line runs through 2 teeth 1/1 or R1 to R3.

Can break straight. Usually diagonal to the side or divided into 2, splitting splits convex chin (figure l = LAMDA).

If the injury is minor: bones + teeth are not displaced (2 bones lean against each other + pulling force of balance muscles).

If there is deviation: up-down or out-in direction.


Patients with little pain, hematoma causes bruising, swelling in the chin area, tearing the skin. Chin area: throbbing pain.

In mouth: Bruising gums + bottom of the hallway and floor of the mouth. May tear the gum lining. The teeth where the broken road passed was wide and wobbly. Possible broken or missing teeth. Little wrong joints.

Manually examine the broken path.


Face position film (Face PA), lower jaw occlusal film (lower jaw occlusal); film at the tip, film Panorex.

Fracture of the lateral region (R3 to jaw angle)

The fracture line is usually between R 3 and R Coi

The fracture line is usually diagonal downward and backward, so the two fractures are displaced due to the tension of the muscles:

Short fracture: pulled upwards + deviated to the floor of the mouth (pulled up by muscles)

Long fracture: deviated downwards + outward (pulled down by muscles)


Pain, failure to chew, difficulty swallowing and pronunciation, facial deformity, chin slightly deviated to the broken side. There may be a subcutaneous hematoma spreading to the cheeks and down the neck. The step defect is felt in the lower margin of the lower jaw. Painful pressure.

Mouth opening: R-arc deformation. Move the two ends of the fracture easily.

Mouth closure: Lift lip and cheek ® short fracture touches upper jaw and long segment is pulled down Þ open bite R door.


Movie face straight: see the entire lower jaw.

Films function (P) or (T) (Incidence Maxillaire Défilé).


Broken jaw angle

Diagonal fracture line down + backward.

Minor injury + fracture line between the grip of the bite muscle and the inner calf muscle: not deviated.

Strong trauma: deviation.

Tall branches are pulled upwards, forwards, inwards.

Horizontal branches pulled down, back.


Mild pain, poor chewing or failure to chew.

Swelling + bruising at the angle of the jaw. An dazzling pain.

In mouth:

If the fracture does not deviate: the bite is perpendicular, so it is difficult to determine, besides the dazzling pain mark, it is necessary to shake to find the fracture.

If the fracture has displacement: the bite is wrong, the jaw is skewed to the broken side.


Straight film.

Movie function.

Film teeth if related to R.8.


Broken branches high

Rarely (high bone short + thick and wide, covered with thick muscles). Vertical fractures are more than transverse fractures of tall branches.


Function: pain, difficulty opening, not chewing.

Outside of mouth: swelling, bruising, pain along the fracture line, chin slightly deviated.

In the mouth: signs of a bipolar bite:

Ask the patient to close their mouth and see the broken side R joint touching the front jaw (due to the shortened side).

Good lateral joint touches back.





Broken neck bridge

Broken neck high bridge: rare. The fracture line is usually horizontal in the sac, deviated much.

Low convex fracture: common, little displacement. The broken line goes from the bottom of S cot , diagonal downward and backward to the high bank.


Function: painful, difficult opening of the mouth.

Outside the mouth: Numb or slightly rough before ear folds, look for signs of dazzling pain in front of ear folds with index finger and little finger, look for protrusions

In mouth:

Wrong bite.

The arc R deflects to the broken side.

Signs of 2-stroke bite.





ZIMBER (Pose through the sockets of the eyes).

Gaping & double mouth tomography (P) (T).

Treatment of the lower jaw fracture

There are two types of treatment:

Orthopedic treatment and surgical treatment.

In the face of a lower jaw fracture, it is always advisable to think about and seek orthopedic treatment because with orthopedic methods, most cases can be solved.

Only when the prognosis of non-surgical orthopedic treatment has few results or the results are uncertain, one should think of surgery or surgery in combination with orthopaedic surgery.