Loose teeth in adults are most commonly caused by periodontal disease and injury to the teeth and mouth. Periodontal disease is a condition in which tartar buildup and the resulting infections essentially eat away at the bone to which teeth are anchored. This allows them to become looser and shift in the mouth. Mouth injury, such a blow to the face, can loosen teeth. Bruxism, or a condition in which a person grinds his teeth together, will also usually loosen teeth over time.
Dentists measure teeth mobility by pressing on the teeth and attempting to wiggle them to see how far they move. Teeth should feel firm and anchored in place. People in the beginning stages of gum disease might not notice loose teeth right away, but a dentist can usually feel the movement. The first sign of gingivitis people typically notice is slightly receding gums that bleed when brushed. If the disease isn't treated at this stage, it can progress to periodontitis. This is the more advanced stage of periodontal disease in which the teeth usually start to loosen rapidly.
Root planing, special mouthwashes and regular dental check-ups can often halt both early and later stages of periodontal disease. Some of the loosest teeth, however, may need to be extracted. Measures such as gum flap surgery and jawbone grafts can sometimes save loose teeth once the gum disease is under control.
A dental injury caused by a blow to the mouth may also be the cause of loose teeth. This type of accidental trauma may actually knock teeth out completely. Today, even extremely loose teeth caused by mouth injury can often be saved by a dentist. If the teeth are only slightly loosened and there is no gum disease present that might interfere with healing, they will often firm back up on their own. If the root of the tooth is knocked completely loose, dental intervention will probably be necessary to save the tooth.
Another common reason for loose teeth is bruxism. Many people grind their teeth together while they sleep, so they have no control over it. A dentist can usually tell if a patient grinds his teeth because of wear and tear where the teeth meet. Special mouth guards can be worn during sleep to prevent this type of damage and take pressure off the teeth. Some dentists will make these guards to fit the patient, though inexpensive guards that can be molded to an individual's mouth are also available in some stores.