Can braces or aligners cause root resorption?

Root resorption defined, and what a review says about the average

The definition here comes from a 2017 study by Gay and colleagues in Progress in Orthodontics: “Root resorption (RR) is described as a permanent loss of tooth structure from the root apex.” That apex is the root’s tip, and the glossary entry on root resorption says more about the word.

A 2019 systematic review and meta-analysis of cone beam computed tomography (CBCT) studies by Samandara and colleagues in the European Journal of Orthodontics concluded: “Although the average OIRR measured with CBCT seems to lack clinical relevance, there are certain factors that may affect OIRR following orthodontic treatment. Nevertheless, due to data heterogeneity and low quality of the included studies, the corresponding results should be interpreted with some caution.” OIRR is orthodontically induced external root resorption.

The 2017 study’s background summarizes earlier literature this way: “RR is usually classified as minor or moderate in most orthodontic patients.” A 2021 overview of systematic reviews in the European Journal of Orthodontics says root resorption “can be considered the most unfortunate complication of orthodontic treatment”. None of these lines is a forecast for one patient.

Heavy force, intrusion, torque and longer treatment in the reviews

The reviews list what goes with more root resorption without settling cause and effect. The 2021 overview, by Yassir and colleagues in the European Journal of Orthodontics, found: “The incidence and severity of OIIRR increase with the fixed appliance, especially with heavy force, intrusion, torqueing movements, increased treatment duration, and treatment with extractions or with long apical displacement (particularly for maxillary incisors).” OIIRR is orthodontically induced inflammatory root resorption, and maxillary incisors are the upper front teeth.

The same overview adds that “the cause and effect relationship between OIIRR and orthodontic biomechanics has not been confirmed”, and “There was insufficient evidence regarding most other treatment- and patient-related factors on OIIRR.”

A 2010 systematic review by Weltman and colleagues in the American Journal of Orthodontics and Dentofacial Orthopedics, whose trials were of fixed appliances, is worded more strongly: “Evidence suggests that comprehensive orthodontic treatment causes increased incidence and severity of root resorption, and heavy forces might be particularly harmful.” It also says “The results were inconclusive in the clinical management of root resorption, but there is evidence to support the use of light forces, especially with incisor intrusion.”

These are findings about groups, not figures for your treatment, and the page on how braces work covers the appliance itself.

Aligners against fixed appliances: where the reviews disagree

Reviews disagree on whether aligners and fixed appliances differ in root resorption, and the sources cited here do not say aligners avoid it. A 2017 study of 71 adults in Progress in Orthodontics concluded: “Orthodontic treatment with Invisalign® aligners could lead to RR”, RR being root resorption, and added that “its incidence resulted to be very similar to that described for orthodontic light forces”. A 2026 review in PLoS One, a single-arm analysis with no comparison group, says minor apical root resorption appears to be among the most frequently reported adverse effects of removable aligners, with certainty of evidence that varies across outcomes.

One side finds less with aligners: a 2026 meta-analysis of six CBCT studies by Yıldırım and Topbas in Healthcare, with low certainty of evidence, says “Clear aligner therapy was associated with lower CBCT-measured external apical root resorption compared with fixed orthodontic appliances” and “The results should be considered exploratory rather than definitive.”

The other side finds no clinically meaningful difference: a 2025 meta-analysis by Kreuter and colleagues in BMC Oral Health, whose analysis covered upper incisors with a moderate to high risk of bias and whose results its authors say should be interpreted cautiously, reports no statistically significant difference between aligners and fixed appliances, and neither group showing clinically relevant root resorption, under 1 mm.

So this is a disagreement, not a finding either way, and no reason to choose an appliance from a page. How an aligner series moves teeth is part of clear aligner treatment.

What x-rays and scans can show about root resorption

The American Association of Orthodontists’ (AAO) February 2026 article on x-rays says “X-rays and scans can reveal hidden decay, root resorption, bone loss, and other conditions that might not be visible during a standard examination.” Its August 2025 article on dental x-rays lists among their uses in orthodontics: “Monitor tooth and root health: X-rays can detect root resorption, cysts, or other problems that might affect long-term tooth health, movement, or stability during treatment.”

Its October 2024 release for adults says “Without taking an X-ray, it is impossible to see anything the naked eye cannot see, such as the health of the tooth roots”.

The 2021 overview in the European Journal of Orthodontics says “Following all precautionary measures, pausing treatment and regular monitoring benefits patients with OIIRR”, its abbreviation for this root resorption. None of these lines gives a schedule or describes this practice; how often x-rays are taken during treatment is a question for the orthodontist.

Your own roots: what to ask the orthodontist

Your own risk of root resorption is not something a review can state, so it goes to the orthodontist, with questions like these:

• What do my x-rays show about my roots now?
• Does my plan involve the movements the reviews list, such as intrusion or torque, or any extractions?
• Would x-rays be taken during treatment?

Adult risks in general are set out under braces or clear aligners for adults, and other questions about treatment day to day are listed together.