The Anglo-Irish Treaty of 1921 divided Ireland into two regions, the Irish Free State, given Commonwealth status and Northern Ireland which stayed part of the UK. Fiona Allison. The Anglo-Irish Treaty brought little peace to Ireland after its implementation: the Irish Free State plunged into civil war.
Tooth sensitivity is caused when the outside of teeth, or the hard enamel, wears down or gums recede and the tiny tubes in the tooth dentin become exposed. Each of those tiny tubes contains a lot of nerve endings, and when they’re left open, it can hurt when you put hot or cold things in your mouth.