A 49-year-old patient complains of constant mandibular pain irradiating to the ear, soft tissue edema, body temperature rise up to 39,0°C. Objectively: there is an edema in the submandibular region, the skin has not changed in colour. Alveolar mucosa around the 45, 46 teeth is hyperemic and edematic on the oral and vestibular side. Crowns of the 45,46 teeth are completely destroyed, the teeth are mobile. Vincent's symptom is present. What is the most likely diagnosis?