Maxillofacial gap infection is a general term for enlarged purulent inflammation of the soft tissues of the oropharynx, face and neck. Purulent inflammation is called cellulitis when diffuse and abscess when confined. Normal maxillofacial layers of tissue between the existence of potential fascial gaps, when the infection invades these gaps, septic inflammation so that the lax connective tissue dissolution liquefaction, inflammation products filled with, the infection can be confined to an interstitial gap, but also through the resistance of the weak tissue diffusion, the formation of diffuse multi-gap infection. Clinical manifestations: the nature of the infection can be purulent or necrotizing; the location of the infection can be superficial or deep, can be confined to an interstitial space, can also be diffused to other interstitial space through the tissue of less resistance, the formation of multi-interstitial infections, and thus have different clinical manifestations. The local manifestations of generalized septic infection are redness, swelling, heat, pain and dysfunction. If the inflammation reflects severely, the whole body shows toxic symptoms such as high fever, chills, dehydration, elevated hundred-cell count, loss of appetite, and general malaise. The local redness and heat signs of putrefactive necrotizing infection are not as obvious as those of purulent infection, but there is extensive edema in the local soft tissues, and even subcutaneous emphysema is produced, which can be palpated and twisted. The clinical symptoms of odontogenic infection are more intense, mostly secondary to alveolar abscess or osteomyelitis, and there is pus formation in the early stage; whereas the inflammation of adenogenic infection is slower, with plasma inflammation in the early stage, and then enter into the suppurative stage, which is known as adenohypoptic cellulitis. Symptoms are relatively mild in adults and sometimes extremely severe in infants and children. Infection occurs in the superficial interstitial space, localized signs are extremely pronounced, and a fluctuating sensation can be detected when the inflammation is limited by suppuration. Infection occurs in the deep interstitial space, due to the dense muscle and fascia around the jaw and the floor of the mouth, the local signs are not obvious, even if the abscess formation, it is difficult to detect the fluctuating sense, but there are localized depressed edema compression pain points. Clinical manifestations of different parts of interstitial infection 1, infraorbital interstitial infection: the infection occurs below the orbit, between the anterior wall of the maxilla and the local expression muscles. Mostly from the maxillary cusp teeth and other odontogenic infections (such as periapical inflammation, etc.), but also from the upper lip or nasal side of the infection. Local manifestations are redness, swelling and pain in the infraorbital region. Lower eyelid edema causing difficulty in opening the eyes. The upper lip is swollen and the nasolabial groove disappears. Erythema at the vestibular groove of the maxillary anterior teeth. The teeth of origin can often be found. Incision and drainage points: generally in the mouth of the maxillary cusp area of the vestibular groove at the bottom of the transverse incision, deep to the bone surface, to the cusp of the concave bone surface separation, in order to achieve drainage. 2.Infection of the subocclusal space: The infection occurs between the lateral bone wall of the ascending branch of the mandible and the occlusal muscle, mainly from pericoronitis of the mandibular wisdom teeth and pericuspid infection of the mandibular molars. It is more common in perimandibular cellulitis. The main clinical features are redness, swelling and pain in the parotid area of the biting muscle centered on the angle of the mandible; due to inflammatory stimulation, the biting muscle is in a state of spasm, resulting in local hardness, restricted mouth opening and even teeth closing; even if the abscess has been formed, the fluctuation of the abscess is not obvious in the early stage and it is not easy to penetrate by itself, therefore, it should be incised and drained in a timely manner. If you are not sure whether the abscess is mature or not, puncture examination is helpful for diagnosis. If treatment is delayed and the abscess is not incised and drained in time, the infection will spread and may lead to osteomyelitis of the mandible. The main points of incision and drainage: make a curved incision parallel to the mandible at 1.5-2cm below the angle of the mandible with a length of about 3-5cm, and incise the skin, subcutaneous tissues, and the vastus cervicis muscle in layers. The lower border of the mandible was then exposed upward, and care was taken to avoid damaging the mandibular marginal branch of the facial nerve and the parotid gland. The occlusal muscle attachment at the lower edge of the mandible is cut, and the pus is separated and drained out upward with a long curved vascular forceps tightly attached to the outer side of the mandible, and drainage is placed. 3.Infection of submandibular space: It is more common in clinic. The infection occurs in the submandibular triangle. Mostly from the infection of the mandibular molar, can also be caused by submandibular lymphadenitis, the latter is especially common in children. Local manifestations include redness, swelling, and pain in the submandibular region, loss of skin lines, and shiny skin, and the lower edge of the jaw may not be visible due to swelling. Severe submandibular cellulitis may spread to the adjacent interstitial space or the neck. Points of incision and drainage: in the lower edge of the mandible about 2cm, make a parallel incision with the lower edge of the mandible to incise the skin, subcutaneous tissue and the vastus cervicis muscle, and then use vascular forceps to separate the drainage. Pay attention to prevent damage to the mandibular marginal branch of the facial nerve. Cellulitis of the floor of the mouth: Cellulitis of the floor of the mouth can be caused by infection of mandibular teeth, acute tonsillitis, acute osteomyelitis of the mandible or secondary infection of trauma to the floor of the mouth. Although rare, it is one of the serious infections of the oral and maxillofacial region. The infection invades multiple spaces in the floor of the mouth. It is clinically categorized into septic and necrotizing cellulitis, with the latter being more serious. The disease is mainly caused by anaerobic, necrotizing bacteria and develops rapidly. The systemic toxic reaction is severe, with weak pulse and shortness of breath, and in severe cases, the body temperature may not rise and the blood pressure may fall. Localized swelling, hardness, dark red skin color, palpation may be twisted. Inflammation usually begins to occur on one side of the sublingual or submandibular area, and later rapidly extends to the under-chin and the opposite side. When the inflammation spreads to the interstices of the floor of the mouth, there is extensive swelling of the submandibular and sub-chin regions bilaterally and even of the upper neck. The head is tilted back and the mouth is half open. Swelling of the floor of the mouth, tongue elevation, and limited tongue movement are seen in the mouth. The patient has difficulty in speech and swallowing. If the swelling spreads to the root of the tongue, it may compress the pharynx and epiglottis and cause dyspnea or even asphyxia. If not timely and correctly treated, the patient’s life can be jeopardized, so we should actively take comprehensive treatment measures. Systemic joint application of high-dose antimicrobial agents, maintain water electrolyte balance, enhance the patient’s resistance, local incision should be timely decompression, drainage, incision is generally from one side of the submandibular to the opposite side of the submandibular, if necessary, can be used for the auxiliary incision of the chin, incision, cut off part of the floor of the mouth muscle to open the pus cavity, placing the drainage. Corrosive cellulitis of the floor of the mouth can also be treated with an oxygen releasing agent such as 1-35 hydrogen peroxide solution or 1:5000 potassium permanganate solution to irrigate and apply wet compresses to the wound. If there is severe respiratory distress, a tracheotomy should be performed promptly to ensure breathing patency.