In short. A cut in the mandible heals like a fracture, over months. What a follow-up scan looks for, what it cannot show, and why it is not routine in the first weeks.
Key points
- Imaging after the operation is used to check the position of the cut surfaces, whether the segments have stayed where they were placed, how the bone is remodelling at the cut edge, and whether there is anything present that should not be, such as a fragment that has lost its blood supply.
- It is a record of the healed state rather than a picture of the result, because the width and the outline are produced by the soft tissue as much as by the bone.
A cut made in the mandible during an angle reduction heals in the same way a fracture does. The two surfaces are held close to each other by the soft tissue envelope and by the rest of the bone, and they unite through a bridge of new bone that is then remodelled over many months. Understanding that process explains both what follow-up imaging is for and why it is not done in the first weeks.
How the bone unites
Bone healing begins with the blood that collects between the cut surfaces and proceeds through a soft bridge that gradually mineralises. That bridge is not as strong as the original bone at first, and it becomes stronger as it is remodelled along the lines of the forces the jaw puts through it. Remodelling continues for a year or more, which is one reason the contour is still changing long after the swelling has gone.
What a follow-up scan is actually for
Imaging after the operation is used to check the position of the cut surfaces, whether the segments have stayed where they were placed, how the bone is remodelling at the cut edge, and whether there is anything present that should not be, such as a fragment that has lost its blood supply. It is a record of the healed state rather than a picture of the result, because the width and the outline are produced by the soft tissue as much as by the bone.
What imaging cannot show
A scan of bone shows bone. It does not show where the nerve is, how much feeling has returned, how the muscle sits over the new contour, or how the jaw looks in a photograph. The result of this operation is read from the face, and the scan is used to answer specific structural questions rather than to judge the outcome. It also cannot say whether the width you see in a photograph will still be there in six months, because that is a question about soft tissue and time.
Why healing does not fill a gap
Bone unites where the surfaces are close together. It does not rebuild a contour that has been removed, which is why the amount taken is treated as fixed at the time of the operation. If too much has been removed, the bone heals in its new position and the shape that results is the shape that was made.
Reasons imaging is brought forward
- Pain over the angle that is increasing rather than settling, especially after the first weeks.
- A segment that feels mobile, or a change in how the teeth meet.
- A wound in the mouth that is not closing, or discharge from it.
Healing is the part of this operation that happens without any help and without much attention. Knowing what it involves is mostly useful for understanding why the shape keeps changing for a year, and why a scan at three months would not answer the question a patient is asking.
Frequently asked questions
How long does a cut in the mandible take to heal?
The two surfaces bridge within weeks, but the bone is not finished then. The bridge mineralises and is then remodelled along the lines of the forces the jaw puts through it, and that remodelling continues for a year or more. It is one reason the contour keeps changing long after the swelling has gone, and one reason the result is judged at around a year.
Do I need a scan after an angle reduction, and when?
Not routinely in the first weeks, because there is nothing useful to see yet and the swelling makes the examination more informative than the image. Imaging afterwards is used when there is a clinical reason, or at a defined point to record the healed state. Your team decides which applies, and it is worth asking what the scan is intended to answer rather than only when it happens.
Can the bone heal in a way that changes the width afterwards?
The cut heals where the surfaces were placed, so the width the bone produces is the width that was made. It does not fill in a gap or rebuild a contour that was removed. What can change the width later is the muscle over the bone rather than the bone itself, which is a separate finding and is assessed separately.
Risks & Limitations
- The change is permanent and the amount removed is treated as fixed. Bone that has been taken away cannot be put back, and material added later does not behave like the mandible it replaces.
- The canal carrying the nerve to the chin runs inside the bone being cut. Numbness of the chin and lower lip is expected rather than rare, usually improves over months, and may not return fully.
- The nerve that moves the lower lip runs near the outer surface of the bone. Weakness after surgery is usually temporary and usually resolves; a lasting weakness is uncommon but possible.
- The vessels supplying the face run close to the surface of the angle. Bleeding afterwards is the complication this operation most wants to avoid, because a collection of blood in the floor of the mouth can compromise the airway.
- The masseter is detached from the bone it was attached to and reattaches. Width can partly return if the muscle thickens again, which is not the bone growing back.
- Swelling hides the result for months. The face reads wider than expected at two weeks, unevenly at three months, and the result is judged honestly at around a year.
When to Seek Care
- Difficulty breathing, a feeling of pressure or swelling in the floor of the mouth, or difficulty swallowing. Seek emergency care at once.
- Swelling that is increasing rather than settling after the first week, or that is much greater on one side. Contact the team.
- Weakness of the lower lip that appears after the first week, or that is worsening rather than improving.
- Numbness that is spreading rather than staying stable, or a wound in the mouth that is opening or discharging.
- Fever, or feeling generally unwell with a swollen and tender jaw. Calf pain or swelling in one leg, or chest pain and shortness of breath, need emergency care at once.
References & Further Reading
- American Society of Plastic Surgeons (ASPS) — procedure and safety guidance
- National Institute for Health and Care Excellence (NICE, UK) — relevant guidance
- Cochrane Library — systematic reviews
- Chinese Medical Association Plastic Surgery Branch — clinical guidance
This page is patient education, not medical advice, and it does not cite individual studies. Discuss your own case with a qualified clinician. To arrange an assessment at Chongqing West District Hospital, see Contact & Consultation.