The most common reason for a loose tooth in an adult is periodontal disease. Periodontal disease (gum disease) is a chronic, low grade infection of the gums surrounding the teeth. It is caused by bacterial plaque which lives in your mouth and attaches to the surface of the teeth both above and below the gum. If enough plaque accumulates under the gum, and remains for enough time, an infection will start. This infection starts in the small spaces between your teeth and gums. The gums react to this process by swelling up and loosening their grip around the individual teeth. This loosening opens up deeper spaces between the gum and tooth allowing for more debris, plaque and food to work their way into the spaces. As the disease progresses, it slowly dissolves the bone around your teeth and, as it shrinks away, the gums may follow. Many times, the patient is unaware of this disease because there is no pain involved until it gets to a more advanced stage. Other symptoms of periodontal disease are bleeding gums (when brushing, or spontaneously), bad breath and receding gums. Many times, by the time an individual notices these symptoms, the disease has been active for quite some time, even years. Periodontal disease can be treated and many of the symptoms can be reversed. You need to tell you dentist about this this week and he might want to see you before your next scheduled appointment. He will diagnosis the severity of your condition and recommend treatment. Many times this disease can be treated with a thorough dental cleaning and root debridement. Once the plaque, infection and inflammatory toxins are removed from between your teeth and gums, the looseness should improve, if not resolve completely. Keep in mind that periodontal disease can not be cured; only treated. After the initial treatment from you dentist, you will need to return a few times a year to him/her for regular dental cleanings. This will keep the disease at bay and prevent it from escalating to the degree that causes bone loss and tooth looseness.
Other reasons you tooth might be loose are grinding of the teeth during the day or night or the pressure from dental abscess under the tooth (but this is normally quite painful) As mentioned before you should call you dentist tomorrow and make an appointment to diagnose the problem. I hope you find this information helpful. If you have any concerns that I have not addressed regarding this matter, please let me know and I will get back to you with more information.
Sincerely, XXXXX XXXXX DDS