Constant pain in the front teeth may be caused by tooth decay, gum problems, enamel wear, a cracked tooth, or nerve sensitivity. It may also occur due to an infection or pressure from the surrounding gums or sinuses. To help relieve it, avoid very hot or very cold foods, and brush gently with a fluoride toothpaste. You may take a simple pain reliever, such as paracetamol, if it is suitable for you. It is important to see a dentist soon so that the exact cause can be identified and properly treated.