People with tongue piercings risk developing gaps between their front teeth as a result of playing with the stud, US researchers have found.
The University of Buffalo team says that, as well as potentially requiring cosmetic work, people can develop infections and chipped teeth.
It discusses a patient in the Journal of Clinical Orthodontics who needed braces to correct the gap in her teeth.
UK experts advised people to "steer clear" of the adornment.
The researchers said that people with tongue piercings were likely to push the metal stud up against their teeth and consequently cause gaps and other problems to arise.
Sawsan Tabbaa, professor of orthodontics at the University of Buffalo, detailed the 26-year-old's case.
She had had no space between her teeth before wearing a barbell-shaped tongue stud.
However, a space had appeared between her upper front teeth over the course of the seven years she had worn it for, because the metal bar was pushed against and between the teeth. BBC News
