A patient complains about acute intense pain and a slight swelling in the area of a decayed tooth of the lower jaw on the right, ill health, body temperature rise up to 38,3°C, lack of appetite, insomnia. Objectively: there is collateral edema of soft tissues of submandibular area and lower part of right cheek. Regional lymph nodes are enlarged on the right, palpatory painful. Crown of the 46 tooth is half decayed, the 45, 46, 47 teeth are mobile, there is also a cuff infiltrate in the area of these teeth. Vincent’s symptom is positive on the right. Make a diagnosis: