Very poor quality of teeth usually includes enamel underdevelopment, tetracycline teeth, teeth misalignment, etc. Some of them can be corrected by wearing braces and braces. 1. Enamel underdevelopment: If in the process of tooth development, endocrine disorders, malnutrition or abnormal calcium and phosphorus metabolism may lead to enamel underdevelopment or poor mineralization, which can be corrected by wearing braces. 2. Tetracycline teeth: If children take tetracycline or doxycycline during the critical period of tooth development, it is possible that the drug combines with the teeth to form tetracycline teeth, which can also be corrected. 3. Poorly aligned teeth: When the teeth are not aligned and the upper jaw is malformed, teeth can be straightened by wearing braces. When there is a bad quality of teeth, you need to consult a doctor in time, with the help of the doctor to clarify the cause of the disease, and targeted treatment or treatment.