If dental caries are not treated, they may further infect and cause inflammation of the dental nerves, leading to pulpitis or apical periodontitis, causing severe pain. When apical periodontitis occurs, it may sometimes lead to a space infection, which is facial swelling. If the inflammation is not controlled in time, it may also cause osteomyelitis of the jawbone. Therefore, dental caries need to be treated as early as possible. Dental caries are caused by bacterial infections that lead to the decay of the hard tissues of the teeth; in the early stages of decay, using a drill to stop the development of the disease—namely, timely filling—can effectively control the further progression of dental caries. If dental caries further infect and cause inflammation of the dental nerves, it can lead to pain while eating or sleeping, sometimes waking from sleep due to pain, and in severe cases, it can cause facial swelling.