of tooth. the infection at the root of the tooth can travel through bone and infect surrounding soft tissue. mouth infections are usually diagnosed on history and physical exam in the dental office or at a clinic visit with an otolaryngologist. swelling within the oral cavity or cheeks, along with a history of progressively worsening tooth pain and fevers, is usually enough evidence to support the diagnosis of a mouth infection. depending on the severity of the infection, further tests may include x-rays and ct scans of the mouth to better characterize the location and extent of the infection. if the infection is drained with a needle or scalpel, then a swab of the infection is collected to identify the microbes present in the abscess and to determine their respective susceptibilities to antibiotics. other lab tests may include a complete blood count with differential, serum electrolyte concentrations, and other routine assays for an infectious workup. treatment although mouth infections can present in many different ways, they are managed according to the same guiding principles - protect the airway, drain the abscess, and treat with antibiotics if necessary. securing a patient's airway is the most important part of initial treatment because loss of airway is emergently life-threatening. inflammation and large abscesses, particularly those within the floor of the mouth, may block airflow into the lungs. to pre-emptively protect a patient's airway, placing flexible plastic tubing through the nasal cavity and into the trachea, called endonasal intubation, is typically the first option. it can be performed with or without direct visualization with laryngoscopy, a small camera with a live video feed to ensure the tubing is placed in the proper location. if attempts to intubate through the nasal cavity are unsuccessful or if the airway must be re-established quickly, then an incision can be made through the front of the neck to gain access into the trachea, also known as a tracheotomy. after stabilizing the patient's airway, extracting the infected tooth will typically promote adequate drainage and the infection will resolve shortly thereafter. if the infection involves multiple primary spaces or any of the secondary spaces previously mentioned, then incision and drainage with culture-guided antibiotics may be indicated. since most mouth infections are polymicrobial, penicillin is an appropriate initial choice of antibiotic because of its activity against streptococcus and gram negative anaerobes. if the patient has a penicillin allergy, then clindamycin with or without metronidazole are also effective empiric antibiotic regimens. additionally, empiric antibiotics should be initiated in patients with a compromised immune system, like those on immunosuppressive medications, with diabetes, or with cancer. in situations where the infection worsens or fails to improve after multiple days, washing out the wound in the operating room should control the source of infection and promote healing.