Root resorption

The definition

Root resorption is a permanent loss of tooth structure from the root apex, the tip of the root, as a 2017 study by Gay and colleagues in Progress in Orthodontics describes it.

Root resorption in a 2017 orthodontic study’s words

Root resorption is defined here from orthodontic research: a 2017 study by Gay and colleagues in the journal Progress in Orthodontics opens its abstract with “Root resorption (RR) is described as a permanent loss of tooth structure from the root apex.” The apex is the tip of the root.

The same study adds a point that keeps the word in proportion, writing that “Several authors demonstrated that RR occurs even without orthodontic treatment”.

Root shortening, and the second sense for baby teeth

Root shortening is the plain phrase for root resorption, and the 2017 study itself speaks of apical root shortening, a shortening at the root tip.

In children’s teeth the word has a second sense. The American Academy of Pediatric Dentistry (AAPD) uses it for the roots of baby teeth, in a guideline sentence on x-ray signs: “Additional potential radiographic signs of maxillary canine impaction include enlarged follicular sac, lack of root resorption of primary canines, and presence of premolar impaction.” There, it is the missing resorption of a baby canine’s root that may point to a permanent upper canine that is impacted.

Where root resorption comes up in orthodontic treatment

Root resorption comes up in orthodontics as a risk the evidence has not fully explained. A 2021 overview of systematic reviews in the European Journal of Orthodontics, by Yassir, McIntyre and Bearn, calls the orthodontic form orthodontically induced inflammatory root resorption, or OIIRR, and concludes: “The influence of fixed appliance on root resorption was noted; however, the cause and effect relationship between OIIRR and orthodontic biomechanics has not been confirmed.”

The risk factors that overview names, and the AAO’s point that x-rays show the health of the roots, are on the page about braces or clear aligners as an adult. Impacted tooth, the term behind the AAPD’s baby-canine sign, has its own page in the orthodontic glossary. What any of this means for your own roots is a question for the orthodontist.

Sources

Gay G, and others, Progress in Orthodontics, 2017, Root resorption during orthodontic treatment with Invisalign®: a radiometric study
Yassir YA, McIntyre GT, Bearn DR, European Journal of Orthodontics, 2021, Orthodontic treatment and root resorption: an overview of systematic reviews
American Academy of Pediatric Dentistry, Management of the Developing Dentition and Occlusion in Pediatric Dentistry
American Association of Orthodontists, Adult Orthodontics FAQs: Your Concerns Addressed

Root resorption and your own roots: a question for your consultation

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