When the upper jaw is too narrow, this results in what is called a transverse maxillary deficiency. This narrowness can cause the upper teeth to bite inside the lower teeth (crossbite), crowding of the teeth, or black corridors upon smiling.
The patient may have a smile that shows mostly the two prominent front teeth, with the others in shadow (buccal corridors). Also crossbites can have a pronounced effect on the overall facial appearance.
With a distraction procedure the upper jaw can be widened until it fits around the lower jaw. Surgery is used to separate the two halves of the upper jaw and a distraction device is placed into the jaw. The patient has to turn the expansion screw of the device every day for about two weeks. New bone fills in between the gradually widened two halves. Orthodontic treatment will close the gap created by the distraction.
Before widening of the upper jaw.
After widening of the upper jaw.
Procedure of distraction
The surgical procedure to make the bone incisions in the upper jaw is the same as previously explained in the Le Fort I osteotomy of the upper jaw. However, to create two halves one more incision is made vertically on the midline of your upper jaw.
A distraction device is placed with a little plate on each side of the palatal bone of the upper jaw. At the end of the operation, a small blocking screw is inserted.
A new consultation is scheduled a week later. The blocking screw will be removed and the activation of the device can start. The distractor has a center screw that must be turned with a key. The divider is “activated” by placing the key into the key-hole in the center screw and then gently pushing toward the back of the mouth.
Each day, we open the palate ± 0,5 mm. So, after 10 days, we can expect an opening of 5 mm between the two front teeth.
The screw usually has to be turned for 1 to 3 weeks depending on the amount of widening needed.
Once the widening of the palate is achieved, the fixing screw is placed again. The distractor should be kept firm and immobile in the mouth for 3 to 5 months. This allows time for new bone to form and ensures that the widening will not relapse.
In this phase, the orthodontist may begin treatment to close the gap between the front teeth.
Later on, the plates on both sides of the palate will be removed surgically under local anaesthesia.