MARPE: Miniscrew-Assisted Rapid Palatal Expansion Explained

MARPE, for miniscrew-assisted rapid palatal expansion, addresses a real clinical gap: a narrow maxilla in a patient too old for a conventional expander to open the suture, who would rather avoid surgery. This guide covers what a MARPE expander is, who it is for, what systematic reviews report on success and side effects, and how it compares with conventional rapid palatal expansion (RPE) and surgically assisted expansion (SARPE). The evidence is mostly observational and of low certainty, and every figure below comes with its source.

What is MARPE?

MARPE is a palatal expander whose screw is connected to miniscrews (temporary anchorage devices, TADs) placed in the palate, so that the force reaches the basal bone of the maxilla rather than passing only through the teeth. Lee and colleagues described it in a 20-year-old patient with a severe transverse discrepancy and mandibular prognathism, expanded before orthognathic surgery (Lee et al., 2010, Am J Orthod Dentofacial Orthop, PubMed). Their condition still holds: it works "assuming that the suture is still patent".

How a MARPE expander is anchored

Expanders are grouped by where they take support (Abu Arqub et al., 2022, Eur J Orthod, PubMed):

In the systematic review by Kapetanović et al., every included study used a tooth-bone-borne appliance, usually with four miniscrews (Kapetanović et al., 2021, Eur J Orthod, PubMed). A finite element study found a higher skeletal-to-dental ratio with a bone-borne device (about 70%) than with a hybrid one (about 49%); it is a simulation, not a clinical result (Ouldyerou et al., 2024, Am J Orthod Dentofacial Orthop, PubMed).

Why MARPE exists: the midpalatal suture after growth

In children, a conventional expander opens the midpalatal suture through the teeth. With age, the suture becomes more interdigitated, more force is needed, and more of the expansion turns into buccal tipping of the anchor teeth, with a risk of buccal bone loss and recession (Kapetanović et al., 2021).

The D.U. courses behind GS Ortho give an ideal age of 10 to 14 years for rapid disjunction, with an upper limit of 14 or 15 years depending on the course. Boileau adds that there is no consensus on the age limit and that the state of the suture (occlusal radiograph, CBCT) should decide rather than age alone. Our article on maxillary endognathia and disjunction (in French) details these windows.

Angelieri et al. proposed five CBCT stages of suture maturation (Angelieri et al., 2013, Am J Orthod Dentofacial Orthop, PubMed):

• stage A: straight high-density line, little or no interdigitation;
• stage B: scalloped high-density line;
• stage C: two parallel scalloped lines, separated in places by small low-density spaces;
• stage D: fusion completed in the palatine bone;
• stage E: fusion extended anteriorly into the maxilla.

In their 140 subjects, stages A and B were seen typically up to 13 years and stage C mainly from 11 to 17 years. Age alone is a poor guide: in a Turkish sample of 180 CBCT scans, 41.7% of people aged 16 or older were still in stage C (Baş et al., 2026, Int Orthod, PubMed).

Indications and age window

MARPE targets a skeletal transverse deficiency of the maxilla (endognathia) in late adolescents and adults. The diagnosis comes first. In the D.U. courses, the main criterion is the inclination of the posterior teeth: teeth tipped inward on a normal base call for dentoalveolar expansion, upright or compensated teeth on a narrow base point to a skeletal problem. Expanding bone for a dental problem, or the reverse, leads to relapse.

Reviews define their populations differently: from 16 years (Kapetanović et al., 2021) or from 13.5 years (Zeng et al., 2023, BMC Oral Health, PubMed). A scoping review of 75 studies reported high efficacy up to 25 years of age (Labunet et al., 2024, Biomedicines, PubMed). None of the sources we read sets a firm upper age limit.

Success rates and what predicts them

"Success" usually means suture opening or reaching the planned width; definitions vary.

• Kapetanović et al. (2021): 8 observational studies, mean success rate 92.5% (95% CI 88.7-96.3%), very low GRADE quality of evidence.
• Zeng et al. (2023): 12 studies, mean success rate 93.87%, also very low GRADE quality.

These averages hide large differences between patients.

Age and sex

• In 215 patients aged 6 to 60, suture separation succeeded in 61.05% of males and 94.17% of females; older age was associated with non-separation in males, not significantly in females (Jeon et al., 2021, Clin Oral Investig, PubMed).
• In 28 post-pubertal patients, success was 83.3% at 15-19 years, 81.8% at 20-29 years and 20% at 30-37 years; sex was not relevant in this sample (Oliveira et al., 2021, Angle Orthod, PubMed).
• With a force-controlled protocol in 32 adults aged 18 to 58, non-surgical expansion succeeded in 84.4%; patients who needed SARPE were older (mean 41.3 vs 26.8 years) (Winsauer et al., 2021, Head Face Med, PubMed).

The literature is not unanimous: a 2025 meta-analysis found no association between age and suture opening (p = 0.701) (Lázaro-Abdulkarim et al., 2025, Med Oral Patol Oral Cir Bucal, PubMed). Samples, protocols and definitions of success differ too much to settle the question.

Midpalatal suture maturation stage

In Oliveira et al. (2021), stages B and C had a 100% success rate, stage D 62.5% and stage E 58.3%. The correlation was not statistically significant, but every failure occurred in stage D or E. Other cohorts found that a more advanced stage reduced the skeletal effect (Yi et al., 2023, Am J Orthod Dentofacial Orthop, PubMed; Shin et al., 2019, Korean J Orthod, PubMed).

Palatal bone thickness

• Palatal bone thickness varies widely between patients and regions, thicker anteriorly near the suture and thin posteriorly; the authors recommend CBCT planning of miniscrew sites (Negrisoli et al., 2022, Am J Orthod Dentofacial Orthop, PubMed).
• In 50 patients, MARPE was more effective with thicker bone at the anterior miniscrew sites and thinner midpalatal bone 18 to 21 mm behind the incisive foramen (Nie et al., 2023, Clin Oral Investig, PubMed).
• In 33 adults aged 18 to 52, older age, thin palatal bone and a higher maturation stage were associated with failure; success was 81.2% with corticopunctures and 33.3% without (Meirelles et al., 2023, Am J Orthod Dentofacial Orthop, PubMed).

These studies are small, retrospective, and do not measure bone at the same sites. Their shared message: assess age, suture stage and palatal anatomy before choosing MARPE, not after a failed expansion.

The MARPE procedure: activation protocols

There is no single protocol. The studies included by Kapetanović et al. (2021) used, among others:

• 1 turn (0.2 mm) per day, starting the day after insertion;
• 2 turns per day, starting 2 days after insertion;
• 1 turn every other day (slow protocol);
• 1 turn per day until suture opening appeared on a periapical radiograph, then 1 turn every 2 days if no opening was found.

With 1 to 2 turns per day, expansion took about 20 to 35 days; across all studies the range was 20 to 126 days. Several studies then kept the appliance for a retention phase of about 3 to 4 months before orthodontic treatment continued. Some teams add a latency period after miniscrew insertion (12 weeks in Winsauer et al., 2021), or corticopunctures in skeletally mature patients (Meirelles et al., 2023).

Skeletal versus dental effects

MARPE does not produce purely skeletal expansion.

• Kapetanović et al. (2021): mean skeletal width increase 2.33 mm, intermolar width increase 6.55 mm; the skeletal component was 35.6% of the total. The authors consider this clinically comparable to the 3.3 mm reported for SARPE in an earlier review.
• Zeng et al. (2023): basal bone 48.85%, alveolar bone 7.52% and teeth 43.63% of the total, with some skeletal and dental relapse over time.

Against conventional RPE, a meta-analysis of six randomized trials (287 participants) found about 1.1 to 1.2 mm more suture opening with miniscrews, and less buccal tipping of the first premolars (about 6°) and first molars (about 3°) (Bi and Li, 2022, Clin Oral Investig, PubMed).

MARPE also increased nasal cavity width (about 2 mm) and alar width (about 1.5 mm) in non-growing patients (Liu et al., 2023, BMC Oral Health, PubMed). Sagittally, a 2026 meta-analysis found small increases in SNA (0.79°) and ANB (1.18°), with no significant vertical change (Xie et al., 2026, Int Dent J, PubMed). Before-and-after values can be compared with our free cephalometric analysis tool.

Risks, complications and failure

A 2026 systematic review of 20 studies reported alveolar bone loss in 11 studies, buccal dehiscence in 3, and failure of suture opening in 6, with gingival hypertrophy among possible effects; certainty was low to very low and follow-up often missing (Frenna et al., 2026, Diagnostics, PubMed). Other findings:

• buccal bone: limited evidence of less loss than with conventional RPE (Copello et al., 2020, Orthod Craniofac Res, PubMed);
• root resorption: limited evidence of less resorption than with RPE (Abu Arqub et al., 2022); upper incisor resorption was measured after MARPE, linked to age and amount of expansion (Chang and Lee, 2024, Korean J Orthod, PubMed);
• age: complications occurred in 18.5% of successful cases in Winsauer et al. (2021), with odds rising with age;
• rare events, from single case reports: a maxillary fracture with infraorbital sensory disturbance at 32 years (Hanai et al., 2025, J Clin Med, PubMed) and an infraorbital neuropathy that resolved within 5 months (Kim and Kho, 2026, Medicine, PubMed).

A scoping review of adults found dentoalveolar side effects mainly with MARPE and surgical complications mainly with SARPE, but only 4 of its 26 studies concerned MARPE (Sicca et al., 2025, Dent J, PubMed). A compromised periodontium may raise the risk (Kapetanović et al., 2021); see our article on adult orthodontics and the periodontium (in French).

MARPE vs RPE vs SARPE: decision criteria

MARPE is not part of the D.U. courses behind GS Ortho. What follows combines the course framework for RPE and SARPE with the literature above. In the clinical rules our team has adopted, miniscrew-assisted expansion is a category of its own, MARPE being its best-known example: reserved for a skeletal deficiency, considered in late adolescence or young adulthood, after the growth peak while the suture is maturing, as an alternative to SARPE, and never as a default. Before or at the peak, conventional RPE comes first; if imaging shows an open suture, RPE is tried first. No upper age is set: "young adult" is not quantified in our sources.

For SARPE, the courses give a deficiency greater than 6 mm, Boileau more than 5 mm in adults (Suri); the expander is kept about 6 months, with relapse of 5 to 25% (Suri, cited by Boileau). Delay, rate and threshold are set with the surgeon. When the transverse problem is part of a larger skeletal discrepancy, see our article on orthognathic surgery indications (in French).

What patients can expect

Data on patient experience are thin. In one randomized trial of 48 adults aged 19 or over, pain on a visual analog scale averaged 6.87 out of 10 in the first two weeks of expansion and 5.11 in the next two; micro-osteoperforations lowered these scores (Elshehaby et al., 2024, BMC Oral Health, PubMed). Active expansion lasted 20 to 35 days with rapid protocols (Kapetanović et al., 2021), followed by retention and the rest of the orthodontic treatment. Slight widening of the nose is reported and should be explained beforehand (Kapetanović et al., 2021; Liu et al., 2023).

For conventional RPE, the courses describe a gap between the upper central incisors around day 3 as a sign of suture opening, to be confirmed radiographically; Boileau notes it may be absent despite real opening. The MARPE studies we read verify opening by radiograph or CBCT and give no typical timing for this diastema.

In practice: a checklist

1. Confirm that the deficiency is skeletal: upright posterior teeth on a narrow base, not teeth tipped inward on a normal base.
2. Situate growth (for example with cervical vertebral maturation, in French) and image the suture before ruling RPE in or out.
3. If MARPE is considered, assess suture stage and palatal bone thickness on CBCT to plan miniscrew sites.
4. Check the periodontium: thin buccal bone or recession raises the risk.
5. Agree on a protocol (turns per day, imaging to confirm opening) and a fallback if the suture does not open.
6. Plan retention and the orthodontic phase that follows.

Frequently asked questions

Is MARPE painful?

Discomfort during activation is reported, but data are limited. In one randomized trial in adults, mean pain scores were 6.87 out of 10 in the first two weeks and 5.11 in the next two, lower with micro-osteoperforations (Elshehaby et al., 2024). For a personal case, ask the orthodontist in charge.

How long does MARPE treatment take?

Active expansion took about 20 to 35 days with rapid protocols, up to 126 days with slower ones (Kapetanović et al., 2021). Several studies then kept the appliance for a 3- to 4-month retention phase before orthodontic treatment continued.

Is MARPE surgery?

No. MARPE is an orthodontic appliance anchored on miniscrews inserted into the palate, although some protocols add corticopunctures for skeletally mature patients. SARPE, by contrast, combines a Le Fort I osteotomy and a median osteotomy before expansion.

Is there an age limit for MARPE?

No firm limit is established. Success fell with age in several cohorts, especially in men (Jeon et al., 2021; Oliveira et al., 2021), while a 2025 meta-analysis found no association with age (Lázaro-Abdulkarim et al., 2025). Suture stage and palatal anatomy matter at least as much as age.

MARPE or SARPE: which is better?

Neither in every case. MARPE avoids an osteotomy and gave skeletal expansion comparable to SARPE in a review of observational data, but it can fail when the suture is fused, especially in older patients. In the courses, SARPE remains the option for fused sutures and large deficiencies. The choice depends on age, suture stage, the size of the deficiency and the periodontium, and is made by the orthodontist with the surgeon.

With GS Ortho

In GS Ortho, the diagnostic studio guides the examination through 12 panels, so the transverse problem is documented before any appliance is chosen. AI places 29 landmarks on the lateral cephalogram for you to check and validate; the decision stays yours. An orthodontist’s opinion can be requested in one click, straight from the case, which helps when MARPE, SARPE and a conventional expander are all on the table. Patient data stay hosted at the practice. The GS Ortho interface is currently available in French.

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