Dental crowding is suitable for orthodontics and can be seen in 60-70% of malocclusions. Dental crowding is due to evolutionary factors, genetic factors, and abnormalities during replacement of teeth. Dental crowding can be divided into two major types in clinical manifestations, as follows: 1. Simple dental crowding: it only manifests as irregular teeth alignment and bad occlusal relationship of the back teeth, but there is no abnormality of the upper and lower jaws, and the patient’s face is normal, but the teeth are just misaligned, which is called simple dental crowding; 2. Complex dental crowding: in addition to the above manifestations of dental crowding, it also manifests as the abnormality of the upper and lower jaws, for example, maxillary protrusion, mandibular hypoplasia, mandibular anomalies and other malformations. Complex dental crowding: In addition to the above manifestations of dental crowding, there are also abnormalities in the upper and lower jaws, such as maxillary protrusion, mandibular retraction, etc., which is called complex dental crowding. If crowding occurs, no matter what type is mentioned above, you should find an orthodontist to correct it in time.