Malocclusion is the problem of misaligned teeth, uncoordinated upper and lower dental arches, differences between dental arches and jawbones, facial deformities and other problems caused by congenital genetic or acquired environmental factors during the growth and development of adolescents, which is synthetically called misaligned malocclusion. In order to prevent malocclusion, the following measures should be taken: 1. Prevent caries of milk teeth: When caries of milk teeth occurs, it may affect the eruption of permanent teeth. If the order of permanent teeth eruption is disordered, the neatness of teeth and bite will have certain problems, so parents must be very concerned about the caries problem of children during the period of milk teeth; 2, oral bad habits: some children will bite the pen, bite the hand, spit out the tongue and so on bad habits when writing homework and thinking problems, all of which will cause the occurrence of oral teeth misalignment and mis(dentition) malocclusion; 3, mouth breathing: need to go to Ear, nose and throat department for respiratory tract examination; 4, sleeping on the stomach or chewing unilaterally, etc. The above problems that may cause malocclusion can be nipped in the bud in order to truly prevent malocclusion.