The causes of gingivitis in children are multifaceted, including local irritants and systemic factors, mainly due to the following reasons: 1, plaque is the initiating factor of gingivitis in children, which is the main reason for its occurrence; 2, the gingival epithelium of the milk teeth is thin, keratinization is poor, epithelial function is poor, susceptible to bacterial infections or trauma and inflammation; in addition, due to the existence of physiological gaps, the temporary dental irregularities are prone to make the plaque buildup, tartar In addition, due to the presence of physiological gaps, temporary malocclusion is prone to plaque accumulation, tartar and food impaction, which stimulate the gums and lead to gingival inflammation; 3, irregular orthodontic treatment, poor restorations, fillings overhanging, open-mouth breathing or open lips and teeth and other oral bad habits, can cause gingival trauma and plaque retention and gingivitis; 4, children’s oral hygiene and cleanliness work is not complete prone to inflammation of the gingiva; 5, children are susceptible to a variety of systemic diseases, such as fever, Diarrhea, etc., can make the periodontal tissue resistance decline induced gingivitis; 6, long-term use of certain drugs, such as anti-epileptic drugs and immunosuppressants, etc., which can cause gingival fibrous hyperplasia; 7, systemic factors on the occurrence and development of gingiva should not be ignored, such as children’s immune system imperfection, endocrine hormonal changes, vitamin C deficiency, etc., so that periodontal tissues are susceptible to bacterial invasion and destruction, resulting in gingivitis occurs.