Teeth lost for half a year without growth is mainly caused by factors such as late eruption of permanent teeth or congenital absence of permanent teeth. 1. Late eruption of permanent teeth: Inflammation of the periapical region of milk teeth or dental trauma will lead to early loss of milk teeth, and early loss of milk teeth will lead to thickening of the gums on the side of the crown of the permanent teeth, resulting in the symptom of late eruption of the permanent teeth; it is necessary to go to the doctor to have dental eruption surgery, that is, to cut open the gums on the side of the crown of the permanent teeth in order to promote the normal eruption of the permanent teeth. 2. Congenital absence of permanent teeth: it will also lead to the appearance of the above symptoms, and it is necessary to go to the doctor for oral radiological examination (such as dental radiographs, panoramic films of the oral cavity, etc.) in order to confirm the diagnosis of congenital absence of teeth; if there is congenital absence of teeth, then the teeth will not erupt, and it is necessary to carry out regular observation and choose the period for orthodontic or restorative treatment in order to restore the normal function of mastication or articulation. It is recommended to consult a doctor for a clear diagnosis and symptomatic treatment to avoid delaying the condition.