A VISIT to the dentist to stop migraine sufferers clenching their teeth while asleep could cut the number of attacks by at least two- thirds, a Belfast doctor says. Philip Lamey, professor of oral medicine at Queen's University, says that teeth clenching in the night causes jaw spasms and triggers morning migraine attacks. A 2mm-thick splint, fitted by dentists and worn over the back teeth at night, could prevent this, he says in General Practitioner.