Is the best age for orthodontic treatment 12 years old? At this stage, teeth are prone to dental caries (worm teeth), which not only affects the chewing function, but also shortens the arch length and leads to crowded teeth after tooth replacement; it is easy to cause lateral chewing and leads to asymmetry of facial development. At this stage, it is easy to produce bad habits such as biting pencil, triangular board, licking teeth, sticking out tongue, stretching down stool and biting mouth and lip, which lead to malocclusion, and then there are early loss of milk teeth, late loss of milk teeth and tonsil hypertrophy, adenoid hypertrophy, chronic rhinitis, upper respiratory and systemic chronic diseases in this period, which can lead to the occurrence of malocclusion. If we treat the malocclusion as early as possible, we can prevent more than 50% of malocclusion from occurring and save time and effort. Which jaw deformities need to be corrected in time before the period of tooth replacement? At this stage, teeth are prone to dental caries (worm teeth), which not only affects the chewing function but also shortens the arch length and leads to crowding after tooth replacement; it is easy to cause lateral chewing and leads to asymmetry of facial development. At this stage, it is easy to produce bad habits such as biting pencil, triangular board, licking teeth, sticking out tongue, stretching down stool and biting mouth and lip, which lead to malocclusion, and then there are early loss of milk teeth, late loss of milk teeth and tonsil hypertrophy, adenoid hypertrophy, chronic rhinitis, upper respiratory and systemic chronic diseases in this period, which can lead to the occurrence of malocclusion. If the treatment of malocclusion is early, more than 50% of malocclusion can be prevented, and time and effort can be saved. Is orthodontic tooth extraction bad for health? Twelve years old is good for orthodontics because the entire dental arch is fully developed and in the peak growth period. However, it is not suitable for all types of malocclusion, such as the early orthodontic treatment of anterior teeth (“enamel”) and malocclusion caused by bad habits during the period of teething (3-6 years old). Which jaw deformities need to be corrected in time before the period of dentition? Anterior teeth retrusion, serious misalignment of individual anterior and posterior teeth, multiple teeth, maxillary protrusion, mandibular recession, or various malocclusions caused by bad habits need to be corrected early. It is recommended to consult a professional orthodontist during the period of teething or tooth replacement.