Stressed-out pupils who are grinding teeth, chewing pencils and finger nails could be damaging their jaws.
Dentists are advising teen- agers that excessive grinding, known as "Bruxism", runs the risk of wearing teeth down, leading to loss of enamel and sensitive molars. Continuous clenching can result in headaches and even lockjaw.
The association recommends a visit to the dentist if jaws, as well as rains, are aching. Relaxation techniques and jaw exercises can also relieve the tension.
Another stress-buster, suggested this week by National Union of Teachers' spokeswoman Olive Forsyth, was for students to take a couple of hours off GCSE and A-level swotting to watch Euro 2000.
But, after England's 3-2 defeat by Portugal, tomorrow's high-pressure clash with Germany may prompt stressed fans to grind their teeth more furiously than ever.
A tooth-grinding fact sheet can be found on www.bda-dentistry.org.uk