A 28-year-old patient presented for an orthodontic consultation. They had a history of previous fixed appliance-based treatment in adolescence. However, their upper fixed retainer had fractured 12 months previously and the patient had noted that their upper teeth were becoming crooked with an asymmetric open bite also developing. What is the likely cause of these changes?

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Send your answers to k.quinlan@nature.com by 23 February 2023. The answer will be revealed in an upcoming issue.

If you would like to send a clinical puzzle, view the details here: https://www.nature.com/articles/s41415-022-5392-2.