--- title: "Jaw Expansion: Children vs Adults UK" url: https://virtualconsultant.online/guides/jaw-expansion-children-vs-adults-uk description: "Children can widen the palate with a simple expander because the mid-palatal suture is still open; adults need surgery (SARPE) once it fuses." updated: 2026-08-09T00:00:00Z publisher: Virtual Consultant Online --- Expansion Children vs Adults RME / SARPE # Jaw Expansion in Children vs Adults: Why Timing Makes All the Difference Children can usually have their upper jaw widened non-surgically with a removable or fixed expander, because the mid-palatal suture is still open and responds to gentle pressure. Adults generally need surgery, because that same suture has fused solid by adulthood. This guide explains why timing changes the treatment options so dramatically, what RME achieves in children, and what SARPE involves for adults who need genuine skeletal widening. [Start Photo Assessment](https://virtualconsultant.online/evaluations/quote) [Compare Costs](https://virtualconsultant.online/costs) ## How the mid-palatal suture works The roof of the mouth is formed by two palatine processes that fuse in the midline at the mid-palatal suture. This suture — like all cranial sutures — is not solid bone throughout childhood. It contains a fibrous, cartilaginous zone of active tissue that allows the two halves of the palate to gradually separate as the face grows. It is this suture that makes non-surgical expansion possible in children: an expander pushes the two halves apart, the suture responds by depositing new bone in the gap, and the arch widens. Once the suture fully ossifies (fuses into solid bone), no amount of orthodontic force will separate it without surgical assistance. ## Growth of the palate in childhood The upper jaw and palate grow significantly throughout childhood, with the most rapid phase occurring in the early mixed dentition (roughly ages 7 to 10) and a secondary phase in early adolescence. The mid-palatal suture begins to interdigitate (develop interlocking bony projections across the fibrous zone) from around age 10 to 11. By the mid-teens, interdigitation is significant enough that expansion becomes progressively harder. Full ossification typically occurs in the late teens to early twenties, though there is variation between individuals. Girls tend to ossify earlier than boys. ## Why expansion is easier in children under 13 Before significant interdigitation, the mid-palatal suture is relatively smooth and opens symmetrically when force is applied. Expansion in children under 12 to 13 is orthopedic — it moves bone, not just teeth. The results are stable, the treatment is well tolerated, and the bone fill in the expanded suture is reliable. After this age, the increasing interdigitation means more force is needed, the suture opens asymmetrically, and tip of teeth rather than true sutural separation becomes the dominant effect. Expansion in teenagers between 13 and 17 is therefore a grey area where some sutural opening still occurs but tooth tipping is a larger component of the result. ## Rapid maxillary expansion (RME) — how it works and what to expect RME uses a fixed expander — typically a Hyrax or a bonded acrylic expander — cemented to the upper molar and sometimes premolar teeth. A central screw mechanism is activated by the patient or parent, usually once or twice daily. Each activation opens the screw by approximately 0.25mm. The median diastema (a gap between the upper front teeth) typically opens visibly within 2 to 3 weeks of starting activation — a reassuring sign that true sutural separation is occurring. This gap closes spontaneously over the following months as the elastic gingival tissue remodels. The expansion phase lasts 3 to 6 months, after which the appliance is left in place passively for 6 to 12 months to allow bone consolidation. ## Expansion amounts achievable RME in children can reliably achieve 10 to 12mm of skeletal expansion in a single course of treatment. This is clinically significant: it can resolve posterior crossbites, create arch space equivalent to the extraction of premolars, and improve nasal breathing by widening the nasal floor. Expansion of this magnitude in an adult without surgery is not achievable — the suture does not open and the result is almost entirely dental tipping with significant relapse potential. ## Suture fusion in adults In adults, the mid-palatal suture is ossified. Applying conventional expander forces to an adult palate does not open the suture — it tips and flares the teeth laterally, creating a dental expansion with buccal inclination that is unstable and prone to relapse. Additionally, the bone on the buccal aspect of the upper posterior teeth is thin in adults, and excessive dental tipping risks fenestration (tooth root exposure through the bone) or dehiscence. For adults who genuinely need skeletal expansion — typically for significant crossbite, moderate-to-severe crowding, or sleep-disordered breathing — the only effective approach is surgically assisted expansion. ## SARPE (surgically assisted rapid palatal expansion) — what it involves SARPE is an oral surgical procedure performed under general or local anaesthesia. The surgeon makes osteotomy cuts through the bone of the upper jaw — typically along the midline and laterally — to release the fused suture and the surrounding bone so that an expander can physically separate the two halves. The expander (usually a bone-anchored device rather than a tooth-anchored one, to avoid tipping) is then activated post-operatively following the same protocol as paediatric RME. Because the bony resistance has been surgically removed, true skeletal expansion occurs even in fully ossified adults. SARPE is performed by an oral and maxillofacial surgeon, often in conjunction with an orthodontist managing the surrounding tooth movement. ## Recovery and results for adults Recovery from SARPE involves swelling and discomfort for 1 to 2 weeks, restricted diet for a similar period, and a return to normal activity within 2 to 4 weeks. The activation protocol begins approximately one week after surgery and follows a similar schedule to paediatric RME. A midline diastema develops as activation proceeds, confirming sutural separation. Results are comparable to those achievable in children with RME, with true skeletal expansion of 8 to 12mm possible depending on the surgical release. Post-expansion orthodontics to correct tooth positions, close any residual diastema, and coordinate arches is required in virtually all cases. ## Retention after expansion Whether achieved in children or adults, expanded palatal width requires retention. Without retention, the elastic forces of the soft tissue and the residual bony architecture will cause some relapse. The standard retention protocol involves leaving the expander in place passively for 6 to 12 months after the expansion phase ends, allowing bone to consolidate in the expanded position. Following removal, a transpalatal arch, a bonded palatal retainer, or an upper removable retainer is used to maintain width during and after orthodontic treatment. Long-term retainer wear is particularly important in adults where bone density and remodelling dynamics differ from children. ## Useful related pages [Palatal Expander UK](https://virtualconsultant.online/guides/palatal-expander-uk) [Palatal Expander for Adults UK](https://virtualconsultant.online/guides/palatal-expander-for-adults-uk) [SARPE Adult Palate Expansion UK](https://virtualconsultant.online/guides/sarpe-adult-palate-expansion-uk) [High Arch Palate and Orthodontics UK](https://virtualconsultant.online/guides/high-arch-palate-orthodontics-uk) [Nasal Breathing and Orthodontics UK](https://virtualconsultant.online/guides/mouth-breathing-orthodontics-uk) This guide is for general information only. It is not a diagnosis, treatment plan, or substitute for advice from a registered dentist or orthodontist. ### Compare next steps [Orthodontist Near Me](https://virtualconsultant.online/locations/orthodontic-treatment-near-me) [Clear Aligners Near Me](https://virtualconsultant.online/treatments/clear-aligners-near-me) [Invisalign Near Me](https://virtualconsultant.online/locations/invisalign-provider-near-me) [Browse Locations](https://virtualconsultant.online/locations) ### Ready for a clearer starting point? Upload guided photos and receive an indication of likely treatment options and pricing before booking appointments. [Get an Online Quote](https://virtualconsultant.online/evaluations/quote) ### Frequently Asked Questions What age is best for palatal expansion? Under about 12 to 13 years old is the ideal window, because that is before the mid-palatal suture in the roof of the mouth begins to interdigitate significantly. Up to that point the suture is still a fibrous zone, so an expander separates the two halves of the palate and new bone fills the gap — genuine orthopedic movement rather than tooth tipping. Interdigitation starts around age 10 or 11 and increases through the mid-teens, which is why expansion between 13 and 17 becomes a grey area with more tipping and less true sutural separation. Once the suture has fully ossified, usually in the late teens or early twenties, skeletal widening needs surgical assistance in the form of SARPE. Can adults have non-surgical palatal expansion? Non-surgical expansion in adults produces dental tipping rather than skeletal widening. The results are less stable and carry risks of gingival recession and root exposure. Genuine skeletal expansion in adults requires SARPE. Your orthodontist should assess whether dental or skeletal expansion is the actual treatment goal. How much wider can RME make the palate? RME can reliably achieve 10 to 12mm of skeletal expansion in children in a single course of treatment. That is a clinically meaningful amount: it resolves posterior crossbites, creates arch space roughly equivalent to extracting premolars, and widens the nasal floor. The mechanism is a screw in a fixed expander, activated once or twice a day, each turn opening it by about 0.25mm. A gap between the upper front teeth usually appears within two to three weeks, which is the visible confirmation that the suture itself is separating rather than the teeth simply tipping. In adults the same appliance cannot produce this — without surgical release the result is dental tipping with high relapse potential. How long does the expander need to stay in? Expect the expander to stay in for roughly 9 to 18 months in total. The active phase — turning the screw — runs 3 to 6 months, and the appliance is then left in place passively for a further 6 to 12 months while bone consolidates in the widened suture. That passive period is the part people are tempted to cut short, and it matters most: the gap created by expansion is initially filled with immature tissue, and removing the appliance before mature bone has formed allows the palate to narrow again. The same protocol applies after SARPE in adults, with activation beginning about a week after surgery. Does SARPE affect breathing? Widening the palate also widens the floor of the nose, so SARPE increases nasal airway volume and many patients report easier nasal breathing afterwards. That effect is one reason the procedure is sometimes considered in adults with nasal obstruction or sleep-disordered breathing linked to a narrow upper jaw. It is not a treatment for obstructive sleep apnoea in its own right, and the size of any breathing change varies between individuals — airway resistance depends on the soft tissues, turbinates and septum as well as bony width. If breathing is part of the reason surgery is being discussed, an ENT assessment alongside the orthodontic and maxillofacial planning gives a clearer picture of what expansion is likely to contribute. How do I know if I need dental tipping or true skeletal expansion? Your orthodontist can assess this clinically and, where needed, with a cone-beam CT scan showing the mid-palatal suture's degree of fusion. In general, patients under 12 to 13 respond with true skeletal movement, while an adult presenting with a narrow arch and crossbite will usually need this question answered before treatment starts, since choosing dental tipping over needed surgical expansion risks an unstable, relapse-prone result. Explore your options Quick links Not sure where to start? 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Upload guided photos and get a tailored recommendation for your teeth and bite. [Start Photo Assessment](https://virtualconsultant.online/evaluations/quote) [Find an Orthodontist](https://virtualconsultant.online/locations) Citation details Title Jaw Expansion: Children vs Adults UK Publisher Virtual Consultant Online Published 2024-06-01 Updated 2026-08-09 URL [https://staging.virtualconsultant.online/guides/jaw-expansion-children-vs-adults-uk](https://staging.virtualconsultant.online/guides/jaw-expansion-children-vs-adults-uk)