The two most frequent causes of an adult's loose tooth is periodontal, or gum, disease and an accidental injury which involves the jaw.
In the event of a vehicular accident, sports injury, or confrontation that resulted in an injury to the jaw, the patient needs to seek immediate dental treatment. The dentist needs to assess the site for nerve damage, gum damage, and chipped or cracked teeth. The examination needs to take place as soon as possible, before further damage occurs. In the case of an accident, the tooth will often tighten back itself within a short time, usually within two weeks. If the tooth fails within two weeks to tighten, the patient needs to contact the dentist again.
Periodontal disease can not only cause a tooth to loosen, it can cause the tooth to literally fall out of the patient's mouth. Gingivitis and other diseases of the gums can be successfully treated if caught in the early stages. Of course, prevention of periodontal disease with good oral hygiene habits is best. However, if a patient notices red or white swollen gums or a loose tooth and immediately seeks dental treatment, the disease can be treated and the tooth may tighten.
During my years of work in the dental field, the only adult patients I saw lose a tooth by way of loosening and falling out were those with severe periodontal disease. These were all patients that did not follow through with periodontal treatment of the disease and good oral hygiene habits after treatment.
Treatment of periodontal disease begins with measurement of the pockets on the gums and root planing, which is a deep scaling and cleaning at the base line of the teeth. This deep cleaning and scaling removes built up plaque and tartar from the tooth underneath the gums and at the gum line. The build up beneath the gum line allows bacteria to grow, causes tooth decay, and causes swollen pockets to form in the gums. These areas may appear red and inflamed or may look whiter than the other oral tissues and puffy.
Root planing will help return the gums to normal health. It may be necessary for the patient to be given a course of antibiotics and a special mouthwash. In many cases of periodontal disease, a root planing at the patient's dentist is enough to eliminate the problem and a loose tooth tighten. In cases of more severe periodontal disease, the dentist may have to refer the patient to a periodontist for further cleaning and scaling.
Regardless of who performs a root planing due to periodontal disease, the patient will be set up for subsequent visits after all four quadrants of the mouth have been cleaned. During these subsequent visits the dentist or periodontist will measure the pockets of the gums again and chart the patient's progress.
Faulty dental appliances are sometimes the cause of a loose tooth, though this is rather unlikely to occur. In the event it does occur, the dentist will be able to resolve the problem with the faulty appliance immediately. The tooth should tighten again within two weeks. If not, the patient needs to follow up with another visit to the dentist.
On even rarer occasions, it is possible to bite into something with a healthy tooth too hard and loosen the tooth. In most cases, though, of a tooth becoming loose due to eating, there is an underlying cause. The patient needs to see their dentist as soon as possible. The dentist will need to assess the tooth for signs of decay, fracture of the tooth, and damage to the gum. If the tooth is otherwise healthy, it should tighten again within two weeks. If it fails to, the patient needs to see the dentist again.
The best course of action if you should find yourself with a loose tooth is to seek an appointment with a dentist as soon as possible. Do not become overly alarmed until you talk with your dentist, but never ignore the situation assuming it will correct itself.