There are a lot of reasons (including a blow to the mouth) why one of your permanent teeth might become loose. The most common: advanced periodontal (gum) disease that has weakened the gum attachment to the tooth. There’s also another, less common reason: you have a grinding habit that’s producing higher than normal biting forces.
Periodontal (gum) disease is the most likely cause of a loose, permanent tooth. This progressive infection causes damage to the gums and bone tissues that hold teeth in place, leading to looseness and ultimately tooth loss. Gum disease, however, isn’t the only cause: although not as common, excessive biting forces over time may also lead