“Buck teeth” is a northern term, but in the south it is often called “whistling teeth”. What causes the child “buck teeth” “whistle teeth”? 1, congenital factors: upper anterior teeth area has multiple teeth, the lower teeth congenital missing teeth, congenital maxillary development is too large or underdevelopment of the jaw. 2.Bad oral habits: finger biting, lower lip biting, mouth breathing. 3.Premature loss of molar teeth in the lower teeth, abnormal order of teeth replacement. 4, nasopharyngeal diseases: rhinitis, adenoid hypertrophy caused by the patient’s mouth breathing, manifested in snoring, waking up in the morning with dry lips. 5, rickets.