If you have a toothache in the back of your mouth due to high temperatures, you should take the appropriate treatment according to the cause of the toothache. Fire does not directly cause toothache. Common causes of toothache include periodontitis, pulpitis and apical periodontitis. Commonly used treatments include general treatment, physical therapy, medication and surgery. 1. Periodontitis: control oral plaque, maintain oral hygiene, remove tartar, with medication. Commonly used drugs are nitroimidazoles such as metronidazole, tetracyclines such as tetracycline, penicillins such as amoxicillin, macrolides such as roxithromycin. If the symptoms are serious, surgical treatment such as flap scraping surgery. 2. Pulpitis: In acute stage, the pulp can be opened and drained to reduce the symptoms, and the common methods to save the pulp include pulp capping, pulp cutting, and so on. The main method to save the affected tooth is root canal treatment. 3. Periapical periodontitis: The pain caused by periapical periodontitis requires root canal treatment to eliminate the inflammation at the root tip, which is ineffective with medication alone and is prone to recurring when the body’s resistance declines. There may be other reasons for back tooth pain such as wisdom tooth pericoronitis, etc. It is recommended to go to the hospital in time and have it diagnosed by a professional doctor for standardized treatment. The above mentioned drugs should be used under the guidance of a doctor, avoid self-medication.