Antibiotics cure a tooth infection by targeting and killing the specific bacteria that caused the infection. Often, these are used in conjunction with a physical treatment, such as a root canal treatment or pus drainage, to stop the infection and restore health to the tooth.
Clindamycin and penicillin-based antibiotics are most commonly used to treat oral infections, including amoxicillin. Penicillin and amoxicillin are both beta lactam antibiotics, and kill certain types of bacteria by attacking the bacteria's cell walls and not letting them synthesize the components to make new cell walls. Without their cell walls, these species of bacteria quickly die. Clindamycin interferes with certain species of bacteria's ability to make new proteins, and this keeps them from growing. The human immune system then quickly kills the remaining bacteria.
Antibiotics along with another treatment, such as a root canal, are very effective at clearing infection of the gums and jaw. If the antibiotics are not taken correctly, however, then the infection may return. If the antibiotics are ineffective, then there is a risk that the bacteria causing the tooth infection may become resistant to that class of antibiotic in the future. If the bacteria becomes antibiotic resistant, then the following infection will be much harder to treat.