Ear pain may be caused by dental caries, inflammation of the ear canal, temporomandibular arthritis and other reasons. 1. Dental caries: Dental caries will involve the dental pulp and cause pulpitis, and there are nerves in the pulp that involve the root of the ear. When biting, it is often manifested as radiating pain, and it will pull half of the face to the root of the ear to produce pain, so when you bite your teeth, the root of the ear hurts. 2. Inflammation of the ear canal: when the patient has otitis media, tympanitis, otitis externa and other ear canal diseases, the skin and muscles around the teeth will be stretched and pulled to the ear when clenching, so the root of the ear hurts when clenching. 3. Temporomandibular arthritis: the temporomandibular joint surface is congested and edematous due to the hard food consumed for a long time, the opening of the mouth is too big, and the biting is disordered, etc. When the patient clenches the teeth, the joints are stressed and the pain reacts to the ear, which results in the pain in the root of the ear when clenching the teeth. The pain in the root of the ear when biting the teeth needs to go to the hospital in time for diagnosis, and according to the doctor’s advice to take appropriate treatment.