The stability of each tooth relies mainly on the synergistic action of the periodontal soft tissues and the periodontal hard tissues together. The causes of tooth loosening can be divided into physiological loosening and pathological loosening. When women’s physiological period, pregnancy or taking certain drugs, the teeth will appear a little transient loosening for physiological loosening, but when the degree of loosening is greater than physiological loosening is called pathological loosening. Pathological loosening is also divided into loosening caused by local factors and loosening caused by overall factors. The loosening caused by local factors includes gingivitis, periodontitis, gum recession, periodontal disease, dental caries, acute and chronic pulpitis, acute and chronic apical inflammation, calculus, food impaction, etc.; the loosening caused by overall factors includes traumatic occlusion, dental trauma, impact, bruise, cyst or tumor of jaw bone, etc.. These factors can be present singly or in concert to cause loosening of teeth. In short, once the teeth become loose, must go to the regular hospital dentistry in time to seek medical attention, some teeth according to the cause of tooth loosening and the degree of tooth loosening through some specialist technology timely treatment can be retained, to avoid missing teeth caused by missing the best time for treatment.