Why was MARPE developed?
The two halves of the upper jaw are joined by a seam (suture) in the middle of the palate. In children this suture has not yet fused, so conventional palatal expansion appliances can open it with the force applied to the teeth. As growth is completed the suture fuses; in this situation, conventional tooth-borne appliances mostly tip the teeth outwards but cannot widen the bone sufficiently.
In MARPE, the expansion screw is attached to small mini-screws placed in the palatal bone. In this way the force is transmitted directly to the bone instead of the teeth, and in suitable patients skeletal expansion is aimed for without surgery.
Who is it considered for?
- Teenagers and adults who have finished or are close to finishing growth
- People with a crossbite of the back teeth and a narrow upper jaw
- Cases where space is needed for crowding and the narrowing is skeletal in origin
- People whose palatal bone and gums are suitable for mini-screw placement
Suitability is assessed through examination, X-rays and, if necessary, three-dimensional imaging (cone beam CT). Age alone is not decisive; the degree of suture fusion varies from person to person.
MARPE, conventional expansion and SARPE compared
| Method | Support | Usually for whom? |
|---|---|---|
| Conventional rapid palatal expansion | Teeth | Children and early adolescence |
| MARPE | Mini-screws placed in the palate (sometimes together with the teeth) | Late adolescence, young adults and suitable adults |
| SARPE (surgically assisted) | Surgically released bone + appliance | Adults whose bone is more resistant |
Which method is suitable is decided according to the person's bone structure, the amount of narrowing and the overall treatment plan.
Stages of treatment
- Records and planning: Examination, X-rays, CT if needed and an intraoral scan; the position of the mini-screws is planned.
- Fitting the appliance: Under local anaesthesia, the mini-screws are placed in the palate and the individually made expander is attached.
- Active expansion: The screw is turned according to the schedule set by the orthodontist; this stage usually takes a few weeks. A temporary gap appearing between the front teeth can indicate that the suture has opened.
- Waiting (retention): The appliance stays in the mouth for a while longer so the opened area can fill with bone; mostly a few months.
- Orthodontic treatment: After expansion, the teeth are usually aligned with clear aligners or braces.
What might you feel during treatment?
- After the screw is turned, a brief feeling of pressure may be felt in the palate, at the bridge of the nose and in the teeth.
- In the first days, speech may change and saliva may increase; most people get used to it quickly.
- The area around the mini-screws should be kept clean with a soft brush and the mouthwash recommended by the orthodontist.
- Avoiding hard and sticky foods helps protect the appliance.
- If the appliance comes loose, or if there is swelling or discharge around a mini-screw, contact the clinic.
Limitations
MARPE may not achieve sufficient skeletal expansion in every adult. If the suture does not open, the treatment plan may be changed and surgically assisted options may be considered. For this reason, expectations should be discussed on the basis of the records before treatment. For more information, see the orthodontic appliances guide and skeletal jaw problems pages.