Abstract: [Abstract] Objective Understand the condition of closure of the first permanent molars in children, and to explore the relationship and the role of various factors that may affect the pit and fissure sealant shedding. Methods 362 children in Harbin who were eligible for pit and fissure closure were selected, and the first permanent molars (1229) were closed with 3 kinds of pit and fissure sealants. The pit and fissure closure was examined at 3 and 6 months after surgery. Statistical analysis of the impact of children oral hygiene, eating habits, psychological factors, the number of surface caries, the kind of pit and fissure sealants five factors on pit and fissure shedding. Results After 3 and 6 months,checking a total of 353 children (1218); 3 and 6 months of pit and fissure expulsion rate was 10.0%, 11.9% respectively. The children of having the low frequency of dietary desserts and carbonated beverages, good oral hygiene, few facets, a quiet mind,and using with Helioseal F have low rate of the pit and fissure sealant shedding (P<0.05). Conclusion The pit and fissure sealant shedding of the first permanent molars of children aged 7-9 years were related to the kind of pit and fissure sealant, oral hygiene, facial number, psychological factors and eating habits.

Key words: the first permanent molars, pit and fissure sealant shedding , multi-factors analysis