If you have not cared for your teeth over the years, such as visiting a dentist regularly for dental cleanings, brushing, and flossing, you will have problems. One of these potential problems is loose teeth. The main thing that causes this problem is periodontal disease. If you do not brush, bacteria will build up and form plaque. If the plaque is left on the teeth, it will cause cavities. The plaque can also get under your gums, causing infection.