Bite abnormalities and bad oral habits Bad oral habits formed during infancy and childhood for some reasons can cause lined-jaw-facial deformities. With the duration of bad habits, the frequency of occurrence and the intensity of action increase, the bite lining relationship is changed and the wrong lining is produced. Correction of bad oral habits should be taken seriously from the nursing period, and correction of mislined should be started after the age of 3 when young children can cooperate. This period of correction time is short, the efficacy is obvious. 1, anterior teeth anterior lined clinical seen: upper and lower milk anterior teeth or replacement period anterior teeth anterior lined, or even for the whole row of teeth anterior lined, lower anterior teeth compensatory tongue to the position of tilt; chin protrusion, face in the 1/3 depression with the increase in age and aggravated; swallowing action can be filled with the tongue between the upper and lower teeth, said live when the mouth teeth slurred, tongue sound heavy. Etiological analysis: The causative factor is the childish swallowing habit. The causes of this habit are as follows: (1) improper feeding posture during lactation, such as the mother lying down to nurse or artificial feeding when holding the bottle from the top down vertically causing the infant to lean forward; (2) artificial feeding after weaning food is too fine, so that young children are allowed to suck the milk way to eat, as shown by eating very slowly or wrapped rice, long fiber vegetables do not chew and easy to vomit heart when swallowing; (3) infant’s Imitation. Genetic factors are rare, but it is common for mothers and infants to have almost identical speech patterns and swallowing habits. 2, anterior teeth open lined clinical seen: the period of milk teeth, teeth replacement and permanent teeth can be seen in the early stage of the anterior teeth without incision, with the tongue forward touch position can be combined with the maxillary anterior protrusion type, bimaxillary anterior protrusion type and anti-lined type; completely without teeth chewing its lined surface is full of tartar; swallowing action can be filled with the tongue body between the upper and lower teeth, say live when the mouth teeth, tongue sound heavy. Etiological analysis: the formation of open lined last manifestation is childish type swallowing, but there are various mechanisms to produce. (1) chewing mode. Breastfeeding for too long, food is too fine and other reasons, resulting in young children “wrapped rice” “package of rice”, or even a mouthful of rice containing a long time only swallowed without chewing, forming a habit. (2) chronic pharyngeal diseases, such as chronic tonsillitis or chronic pain of pharyngitis, so that children swallowing tongue forward to avoid or alleviate the pain, and become a habit; (3) nasal factors. Chronic rhinitis, sinusitis, turbinate hypertrophy and other obstruction of the normal nasal breathing channel, open-mouth breathing, and over time into a habit. (4) Imitation factors. If it is a genetic factor, we have not seen three generations of open lined people clinically in this area; it is common for mother and child, mother and daughter similar people, the degree of open lined is not great, and the way of pronunciation is similar. Mother and child face to face for a long time from the language learning to produce imitation effect. (5) Other factors. Rickets, high lined teeth and other factors. 3, anterior protrusion type deep lined clinical seen: maxillary protrusion and deep lined are obvious, open lips and teeth, lower lip curl jaw retraction is significant, the lower 1/3 of the face is short, both sides of the cheek into, sucking and biting fingers or biting the lower lip. Etiological analysis: there are genetic and bad habit factors. (1) The maxillary protrusion of yellow people is greater than that of Caucasian people, and it is mostly seen in people with genetic factors causing maxillary protrusion; (2) incorrect artificial feeding. (3) sucking fingers and biting the lower lip makes the lower jaw anterior extension obstructed, resulting in excessive development of the upper jaw forward and restricted development. 4, mandibular deviation Clinical findings: mandibular chin deviation to one side, unequal mandibular body lengths on both sides, inconsistent upper and lower central incisors, upper and lower teeth on the too-small side lined against the edge or antilined, lateralized chewing, most of the mandibular protrusion accompanied by childish swallowing. Etiology analysis: there are the formation of lateral chewing habit and one side of mandibular ascending branch or condylar pathological factors. (1) The untreated caries of milk teeth or the delayed process of milk tooth loss makes one side painful and turn to the other side to eat to form a habit, and when combined with childish swallowing habit, the mandibular deviation and protrusion at the same time. The chewing side is smaller than the disuse side. (2) The growth and development of the temporomandibular joint on one side is impaired due to trauma during the period of deciduous teeth or teething, which makes the mandibular body asymmetrical and oblique on both sides, and such cases are also complicated by the symptoms of temporomandibular joint ankylosis and difficulty in opening the mouth. The affected side is short and small. (3) Pathological expansion of the tumor, and the affected side becomes larger. 5, nocturnal molar clinical seen: upper and lower incisal edge and lined surface can be seen evenly abrasive surface, grinding occurs at night when sleeping, some data show that its incidence up to 15%, mostly by relatives on behalf of the complaint. Etiology: such cases are mostly seen in children who are emotionally rich and easily agitated, and also unpredictable during sleep, often accompanied by finger sucking, nail biting and other habits; also seen in certain diseases, such as parasitic diseases, gastrointestinal disorders, epilepsy, meningitis, etc.