You had braces as a teenager, and for years your teeth stayed straight. Then the retainer cracked or got lost, and nobody replaced it. Now a lower front tooth has turned, or a gap you once closed is back.
If your teeth shifted after braces, you are far from the only one. Dentists call it relapse, and it has physical causes. Clear aligners can move a mild shift back, but without a retainer afterward the same forces move the teeth again.
One honest note first: we provide clear aligner treatment at Front Royal Dental Group, and we do not place braces. If your teeth need braces, I will tell you and point you to a practice that places them.
Why have my teeth shifted after braces?
To see why teeth move back, start with how braces moved them. Nothing cements a root into the jaw: it hangs in its socket from a thin sheet of fibers called the periodontal ligament. When braces press on a tooth, bone dissolves on the pushed side and new bone forms behind it, so the tooth travels.
A 2021 review of orthodontic retention lists the forces behind relapse (Millett, 2021). They include the gums and ligament, the lips, cheeks and tongue, the bite, growth, and normal aging. Here are two of them, and the change that lets them act.
The gum fibers pull back
The ligament around the root rebuilds around the new position. The fibers in the gum around the neck of the tooth do not settle as readily, and they are elastic. When braces turned a tooth, those fibers were twisted with it. They keep pulling it back toward where it started, like a stretched rubber band.
The evidence for this comes from cutting them. A study that began with 320 patients and ran for nearly 15 years cut these gum fibers after braces in one group. That group relapsed less than the group without the cut. The cut was a little more effective against turning than against front-to-back movement (Edwards, 1988). This is why a tooth that was turned straight tends to turn back.
The arch keeps shortening in adulthood
This part happens with or without braces. An Iowa growth study measured the same 30 people from age 3 to age 45. The length of both arches in front of the first molars grew through childhood, then shrank steadily up to age 45 (Bishara et al., 1998). In patients treated with braces, arch length and width also typically shrank after retention (Little, Wallen and Riedel, 1981). That held whether treatment had widened the arch or not.
A shorter arch holds the same number of teeth in less room, so the front teeth start to overlap.
The retainer stopped
A retainer holds the teeth while the gum fibers settle, and then against the slow drift of the arch. Once it lives in a drawer, nothing pushes back against either force.
How common is it for teeth to move after braces?
Common, even after a full course of braces and retainers. One study checked 65 patients, all treated with braces and premolar removal, at least 10 years after they stopped wearing retainers. Two thirds had lower front teeth that were no longer acceptably aligned (Little, Wallen and Riedel, 1981).
The researchers could not predict who would relapse, because age, sex and how crowded the teeth were at the start told them nothing useful.
Can clear aligners fix teeth that shifted after braces?
It depends on what moved and how far. The forces above produce shifts like a lower tooth that turned, front teeth that overlap, or a gap that reopened. Clear aligners move teeth with a series of trays, each shaped slightly differently from the last. Each tray presses the teeth toward its shape, and the bone remodels the same way it did under braces. A small shift of that kind is movement aligners can make.
Where do aligners fall short?
Aligners do not always get a tooth all the way to the planned spot. A 2020 study of one aligner brand, Invisalign, measured 38 patients. On average, teeth reached 50% of the movement planned in the software. Tipping a tooth toward the cheek or tongue was the most accurate movement, at 56%. Turning was the least accurate at 46%, and one direction of turning an upper canine reached only 37% (Haouili et al., 2020).
That matters here, because a turned tooth is the kind of relapse the gum fibers cause. A turn may take more than one round of trays. When teeth lag behind the plan, a new scan and another set of trays continue the movement, which adds time.
A 2019 review of eight studies compared aligners with braces (Ke, Zhu and Zhu, 2019). Aligners were less effective at controlling the tilt of a tooth's root and at getting the upper and lower teeth to meet well. If your shift needs that kind of control, we refer you to a practice that places braces.
One more condition comes before any tray. Moving teeth through inflamed gums puts the bone around them at risk, so gum disease has to be under control first.
Will my teeth move again after aligners?
They will if nothing holds them. Correcting the shift stretches the gum fibers again, and the arch keeps shortening through adulthood.
A 2023 Cochrane review included 47 trials covering 4,377 people treated with braces. Its authors could not name a best type of retainer, because the evidence was low to very low certainty (Martin et al., 2023). Its starting premise is plain: without a phase of retention, teeth tend to return toward their starting position.
A retainer is either removable, such as a clear plastic tray, or fixed, a thin wire bonded behind the front teeth. Before you start, ask how often to wear the retainer, how long it lasts and what a replacement involves.
If you still have your old retainer and it only goes in with force, stop wearing it and bring it to your exam. It was shaped to where your teeth used to sit.
What to do
Start with an exam. A dentist checks your gums and bite, takes a digital scan, and tells you whether your shift is aligner work or braces work. You get a written estimate before anything starts, and you can ask whether the retainer is part of it. For the day-to-day side of wearing trays, our earlier post on clear aligners in Front Royal walks through it. You decide from there whether to go ahead.
Ready to get started? Schedule a visit with Front Royal Dental Group, or call (540) 636-2003.
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