May 26, 2025 | Mars Orthodontics
For decades, the prevailing view in orthodontics was that once an adult’s midpalatal suture had fused, the upper jaw could no longer be widened without surgery. Many adults are still told today that the only option to address a narrow upper jaw is a surgical procedure such as SARPE (surgically assisted rapid palatal expansion), performed by an oral and maxillofacial surgeon.
That view has changed. Modern miniscrew-supported expansion techniques, supported by 3D imaging and specialist-led treatment planning, now allow many adult patients to achieve true skeletal expansion of the upper jaw without surgery.
The technique is called MARPE (Miniscrew-Assisted Rapid Palatal Expansion). At Mars Orthodontics in South Brisbane, we deliver MARPE through our own protocol, which we call MARS-PE: a personalised, specialist-designed approach to adult palatal expansion. Whether you have seen it written as MARS-PE or MARSPE, both refer to the same approach.
This article explains how MARPE works, what the MARS-PE protocol is, how it is delivered, and what adult patients considering non-surgical palate expansion should understand before treatment begins.
MARS-PE is the protocol used at Mars Orthodontics for adult and late-adolescent palatal expansion. The acronym describes the framework:
The central principle of MARS-PE is straightforward: the protocol is matched to the patient, not the patient to the protocol. Every appliance is custom-designed by the treating specialist based on detailed CBCT-based planning, and the activation pathway is selected to suit the individual patient.
MARS-PE personalisation also extends to addressing the bite at the same time as the transverse problem. Where clinically indicated, expansion is combined with additional orthodontic mechanics to address Class II or Class III tendencies, so the treatment is doing more than one job concurrently. The specific combinations are determined case by case at the specialist assessment.
Most adult palatal expansion is described in terms of the appliance used. The MARS-PE Protocol is described in terms of the clinical framework that surrounds the appliance: how the patient is assessed, how the appliance is designed, how the activation pathway is selected, and how the rest of the bite is managed alongside expansion.
This matters because the right activation pathway depends on the individual patient. The same appliance can be activated rapidly or slowly, and the pathway that suits one patient may not suit another. Deciding which approach fits is part of what the protocol is designed to do.
MARS-PE is the framework that determines which approach is appropriate for which patient, and how the broader bite is managed during the same treatment period.
Adult palatal expansion is not a single decision. It is a series of decisions that need to be made together: whether expansion is possible without surgery, how much expansion is required, which appliance design fits the patient’s anatomy, which activation pathway is appropriate, and how the bite will be managed during and after expansion.
These decisions are made by the specialist orthodontist through a thorough clinical assessment. Diagnostic imaging supports that assessment by giving the specialist the detailed information they need.
At Mars Orthodontics, the assessment is supported by two imaging technologies that work together:
These two datasets are then superimposed in specialist treatment planning software, merging the skeletal view from the CBCT with the precise surface anatomy from the iTero into a single 3D model. This allows expansion to be planned against the patient’s actual bone and teeth together, not just the visible surface or the skeletal view alone. It is one of the technical foundations that allows MARS-PE to be planned with the level of detail it requires.
The assessment also identifies whether you may need to see other health professionals as part of your treatment plan. Depending on the case, this may include referrals to a periodontist, a sleep physician, an ENT specialist, an oral and maxillofacial surgeon, a myofunctional therapist, or a physiotherapist. If you are already working with other health professionals, we welcome their involvement, because a collaborative approach often produces the best result.
It is also important to be honest about what MARPE can and cannot do. MARPE widens a narrow upper jaw. It is not a solution for every problem. Complex cases involving significant facial asymmetry, a severe jaw discrepancy, or a skeletal open bite may still require orthognathic surgery, and MARPE does not change that. The appliance itself sits on the roof of the mouth and affects speech during treatment. Many patients notice a lisp while the expander is in place, particularly with “s” and “th” sounds. Most adapt over time, though some find it takes longer than expected. Some patients also have concerns such as TMJ symptoms that may need their own therapy. These things are discussed openly at your assessment so you have a clear and honest picture of what your treatment involves and what it can realistically achieve.
At the initial consultation, the records are taken and the patient receives a clear overview of their case: whether non-surgical expansion is realistic, the likely treatment direction, an honest sense of timeline, and where the case sits in terms of complexity. The detailed appliance design and pathway planning is extensive work that takes place after the consultation, once the patient has decided to proceed. The next in-person appointment after that is the fitting of the appliance and the start of treatment.
A defining feature of the MARS-PE Protocol is that both rapid and slow activation pathways are available, and the choice is made based on the individual case.
Rapid activation can suit younger adults whose clinical presentation supports a faster expansion phase. The advantage is speed during the active expansion phase. The trade-off is that rapid expansion produces a visible midline gap that then needs to be closed during the alignment phase that follows.
This pathway suits patients for whom avoiding a visible gap during treatment matters, and patients who are suitable candidates for concurrent Invisalign. Suitability is determined at the specialist assessment.
With the rapid pathway, the midline gap that opens during expansion is closed afterwards, as part of the broader alignment phase that follows. The rate at which the gap closes depends on multiple factors, not just the size of the gap itself. These include:
Under continuous orthodontic force, the rate of orthodontic tooth movement during space closure is typically in the order of 0.5 to 1 millimetre per month (Dixon et al., 2002), but the actual closure timeline depends on how the gap interacts with the broader treatment plan.
MARS-PE addresses transverse deficiency, meaning a narrow upper jaw. If the main skeletal issue is that the upper jaw is too narrow, MARS-PE can often replace surgical expansion (SARPE) in carefully selected adult patients.
If there is also a significant Class II or Class III skeletal discrepancy, marked facial asymmetry, or a skeletal open bite, orthognathic surgery may still be required to correct those components of the problem.
In these more complex cases, MARPE does not necessarily eliminate the need for jaw surgery. What it may do, however, is simplify the surgical pathway. Rather than requiring two separate surgical procedures, one to widen the upper jaw through SARPE and another to correct the jaw position, the widening of the upper jaw may instead be managed non-surgically with MARPE through the MARS-PE, also written as MARSPE, protocol. This may leave only the orthognathic procedure required to address the jaw discrepancy itself, which may involve single-jaw or double-jaw surgery Where orthognathic surgery forms part of the treatment plan, the final surgical approach and sequencing will be determined in conjunction with the Oral and Maxillofacial Surgeon (OMFS).
A specialist orthodontic assessment with CBCT imaging is the only reliable way to determine what an individual case requires.
Adults considering MARPE often ask what daily life is like during the expansion phase:
It depends on the activation pathway. With rapid activation, a visible gap (diastema) opens between the upper front teeth as the suture separates. This is expected, and it is closed afterwards during the alignment phase of treatment. With the slow pathway, where MARPE and Invisalign run together from the start, expansion happens gradually alongside tooth alignment, so a noticeable gap is generally avoided rather than created and then closed later. Which pathway applies to you is determined at your assessment.
This is discussed and decided with you at your consultation. It depends on your treatment goals and expectations, any previous orthodontic treatment, any previous surgery or trauma, your periodontal condition, and more. Everyone is different, which is why the decision is made together once the full picture is clear.
In many cases, yes. MARPE addresses transverse deficiency, so if the only issue is a narrow upper jaw, it can often replace surgical expansion in carefully selected adult patients. If there is also a significant Class II or Class III skeletal discrepancy (where the jaws are also out of alignment front-to-back), orthognathic surgery may still be required for that separate component. The full assessment determines what your case requires.
Mars Orthodontics is a small boutique specialist orthodontic practice in South Brisbane, dedicated to personalised, specialist-led care. MARS-PE treatment is planned and designed by Dr Carmen Karadeniz, registered specialist orthodontist, and delivered by her husband Dr Ersan Karadeniz, who places and fits the MARPE appliances. As a husband-and-wife team, the two of them personally guide you through every stage of treatment, from your first assessment through to retention. You are personally cared for by Dr Carmen and Dr Ersan at every stage, with no associates or rotating clinicians.
Both Dr Carmen and Dr Ersan undertake ongoing learning with leading clinicians and pioneers of adult palatal expansion in the USA, integrating contemporary evidence-based protocols into their adult expansion cases.
Each case begins with a specialist orthodontic assessment that includes Planmeca Viso G7 CBCT imaging, iTero Lumina digital scanning, and airway assessment. The two datasets are superimposed to plan expansion against the patient’s underlying bone and surface anatomy together. The appliance is then custom-designed for the patient before being fitted at the next appointment, with the activation pathway and bite plan locked in from the outset.
You may also wish to read What to Expect at a MARPE Consultation, learn more about MARPE treatment at Mars Orthodontics, or read Can Adults Get a Palate Expander?.
If you have been told you need surgery to widen your upper jaw, or you have been advised that adult palate expansion is not possible, a specialist orthodontic assessment with detailed 3D imaging can clarify whether MARPE is appropriate for your case.
