It is not safe to buy filling materials online to fill the tooth by yourself, which may cause infection, trauma and other results as follows. 1. Infection: filling teeth by yourself cannot guarantee aseptic operation, bacteria in the instruments and environment may enter the open wound, leading to cross-infection and secondary infection. Caries-causing bacteria still exist in the tooth tissue and caries will continue to develop. 2. Trauma: When a person who has not been professionally trained fills a tooth, he or she is unable to complete the formal and correct operation process, which may cause more damage to the existing caries or damage to other hard and soft tissues, and in serious cases, endanger life and health. When caries occurs, it is recommended to go to the hospital in time to receive professional treatment with the help of doctors.