The main hazards of missing teeth are as follows: 1, occlusal relationship disorders, dental integrity has been damaged, missing teeth, if not for a long time to repair, neighboring teeth due to the loss of support and constraints, will become tilted, maxillary teeth will be elongated, which over time will also lead to the original set of teeth space becomes smaller, difficult to set teeth or even can not set teeth; 2, cause dental caries, missing teeth are not repaired in time, the missing teeth will be tilted to the side of the gap under the force of chewing. Neighboring teeth will be tilted to the side of the gap under the force of chewing, easy to cause food impaction caries; 3, cause food impaction, normal teeth are arranged very tightly between the teeth, neighboring teeth will appear after the teeth and teeth will appear between the gap, easy to make the food impaction to the teeth gap caused by halitosis, caries, periodontal disease, etc.; 4, caused by periodontal disease, individual teeth missing patients like to choose not to have a missing tooth side for partial side mastication. The side without missing teeth for partial chewing, the waste side due to the loss of long-term self-cleaning effect has a large amount of tartar deposition, resulting in periodontitis, while the missing side of the jaw teeth lost the original chewing stimulus, will gradually to the direction of the missing teeth to elongate, resulting in occlusal trauma as well as occlusal relationship of imbalance; 5, induced temporomandibular joint disorders, missing teeth for a long time without teeth, due to the tilt of the teeth, the elongation of the jaw will impede the normal function of the jaw movement, so there will be joint popping, pain and discomfort, the joints and the jaws will be able to move. Therefore, a series of symptoms of TMJ disorder such as joint popping, pain, joint limitation will occur, and once TMJ disorder occurs, it is very difficult to cure it completely; 6, affecting the aesthetics, due to the lack of front teeth will lead to the weakening of the effect of facial and lip support, resulting in facial and lip aesthetics, and at the same time, affecting the normal pronunciation and social functions.