The Gap After Getting an Expander Is Normal: What's Really Happening in Your Child's Jaw
Posted on 2/8/2025 by NC Pediatric Dentistry |
 If your child recently got a palatal expander and you’ve noticed a gap forming between their two front teeth, take a breath: this is completely normal and actually a sign the expander is doing its job. It’s one of the most common questions parents ask our orthodontic team at NC Pediatric Dentistry, and the answer is reassuring.
In this post, we’ll explain why that gap appears, what’s happening inside your child’s jaw during expansion, and how the space closes once the active phase is complete. Understanding the process can make those first few weeks feel much less stressful.
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Why the Gap Forms After Expansion
A palatal expander works by gradually widening the upper jaw. In children and young teens, the two halves of the upper jaw (the maxilla) are connected by a flexible joint called the midpalatal suture. This suture hasn’t fully fused yet, which is exactly why expanders work so well during childhood.
Each time you turn the expander’s key, the device applies gentle outward pressure on the two halves of the palate. As the suture separates, the two central incisors, which sit on opposite sides of that joint, move apart. The result is a visible gap between the front teeth that can appear within the first week or two of treatment.
The gap is direct visual evidence that the jaw is actually widening. Without it, there would be reason to question whether the expander was working at all.
What’s Happening Inside the Jaw
Beneath the surface, the expander is creating space at the skeletal level, not just moving teeth. As the suture opens, the body responds by generating new bone tissue to fill the gap. This process is called osteogenesis, and it’s the same natural healing response the body uses to repair a broken bone.
During the active expansion phase, which typically lasts two to four weeks, you’ll turn the key once or twice daily based on your pediatric dentist’s instructions. After the prescribed turns are complete, the expander stays in place for several more months. This retention period gives the new bone time to mature and solidify, stabilizing the wider jaw shape permanently.
The suture itself is only a few millimeters wide at the point of maximum expansion. But those millimeters make a significant difference in creating room for crowded teeth, improving airway function, and setting the stage for a more balanced bite.
When the Gap Closes
This is the part most parents are eager to hear. Once the active turning phase ends, the gap between the front teeth typically begins closing on its own within a few weeks. The elastic fibers in the gum tissue naturally pull the two front teeth back toward each other.
For most children, the gap is noticeably smaller within one to two months and fully closed, or nearly so, by the time the expander is removed. In some cases, the remaining space is addressed during a later phase of orthodontic treatment if braces or aligners are part of the overall plan.
It’s worth noting that the gap doesn’t close because the jaw is “shrinking” back. The bone that formed in the suture stays in place. The teeth simply drift together through the new, wider arch. Your child keeps all the width that was gained.
Tips for Parents During Expansion
The expansion phase is short, but it comes with an adjustment period. Here are a few things that can help your child stay comfortable and keep the process on track.
Soft foods are your friend during the first few days after the expander is placed and after each key turn. Yogurt, scrambled eggs, pasta, and smoothies are all easy options. Your child may feel some pressure across the bridge of the nose or behind the eyes after turning the key; this is normal and usually fades within 15 to 20 minutes.
Keeping the expander clean matters. Food can easily get trapped around the device. A water flosser or a simple rinse with water after meals helps prevent buildup. Our parent resources page has additional tips on supporting your child through orthodontic treatment.
Stick to the turning schedule your orthodontist provides. Skipping turns or doubling up can both affect results. If you’re unsure whether a turn was completed, it’s better to skip that session and resume at the next scheduled time rather than risk turning twice.
Next Steps for Your Child’s Smile
A palatal expander is one of the most effective early orthodontic tools available, and the temporary gap between the front teeth is simply part of the process. If your child is experiencing crowding, crossbite, or breathing difficulties related to a narrow palate, visit our Locations page to find the NC Pediatric Dentistry office closest to you and schedule an evaluation.
Frequently Asked Questions
How big does the gap between the front teeth get?
The gap varies, but it’s typically a few millimeters wide at its largest. Some children develop a wider gap than others depending on how much expansion is needed.
Does the expander hurt?
Most children feel pressure rather than actual discomfort after each turn. The sensation usually lasts 15 to 20 minutes. Over-the-counter children’s pain relievers can help if needed, but many kids adjust quickly.
What age is best for a palatal expander?
Expanders are most effective while the midpalatal suture is still flexible, which is typically between ages 6 and 14. Your orthodontic team will evaluate your child’s jaw development to determine the ideal timing.
Will my child need braces after the expander?
Not always, but many children do benefit from braces or aligners after expansion to fine-tune tooth alignment. The expander addresses jaw width; braces address individual tooth positioning. Your dentist will outline the full treatment plan early on.
How long does the expander stay in after the turns are done?
The expander usually stays in for three to six months after active expansion ends. This retention period allows the new bone in the suture to fully harden and stabilize.
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