What is a retruded upper jaw?
A retruded upper jaw (maxillary retrusion or maxillary hypoplasia) means the upper jaw has not grown forward enough. Orthodontically it is mostly seen together with a “Class III” bite. From the outside the lower jaw may seem to be in front, but the source of the problem is not the size of the lower jaw; it is the upper jaw lagging behind. This distinction directly affects the choice of treatment.
Signs
- Lower front teeth closing in front of the upper front teeth (anterior crossbite)
- A flat or sunken look around the cheeks and the sides of the nose
- A concave facial profile
- Crowding of the upper teeth and canines that tend to become impacted
- An upper lip that looks thin and set back
Causes
- Hereditary factors; a similar facial structure in the family
- A narrow upper jaw and palate
- Mouth breathing and upper airway problems
- Congenital conditions such as cleft lip and palate
- Early loss of baby teeth
Upper jaw advancement during growth
Face mask (reverse headgear)
Elastics attached between a frame resting on the forehead and chin and an appliance in the mouth apply a forward force to the upper jaw. The aim is to support forward growth of the upper jaw. The face mask is usually worn at home and at night for a set number of hours a day. Its effect is most marked at an early age (mostly 6–10).
Use together with palatal expansion
A face mask is often used together with a palatal expansion appliance. Expansion can help advancement by mobilising the sutures around the upper jaw, and it also corrects a narrow palate.
Mini-screw (bone-anchored) methods
In older children, elastics anchored to mini-screws or mini-plates can be used so that the force is applied directly to the bone. Whether these methods are suitable is assessed according to age and the case.
Follow-up after treatment
Because a retruded upper jaw is often accompanied by a tendency for the lower jaw to grow, regular follow-up until growth ends is important after early treatment. Some children may need further treatment in adolescence.
Options for adults
In people who have finished growing, upper jaw growth cannot be guided. In mild and moderate cases, the bite can be improved by adjusting the position of the teeth (orthodontic camouflage), using clear aligners or braces. With a marked skeletal retrusion, surgically moving the upper jaw forward is considered. For details, see the skeletal problems page.