Abstract: PURPOSE: To investigate the difference of parent's cognition of children's space loss and its influencing factors, to provide reference for children's oral health education, in order to reduce the incidence of malocclusion. METHODS: A self-designed questionnaire was used to investigate the basic information and related problems of 36 parents whose children received space loss treatment. SPSS 22.0 software package was used for statistical analysis. RESULTS: Parents paid more attention to the common oral problems of their children, the awareness of oral prevention and health care were weak, the attention to treatment was higher than that of prevention. The attitude of parents to the cognition and targeted treatment of malocclusion caused by space loss was low(27.78%), which was significantly different from that of caries (75.00%) and premature loss of deciduous teeth (63.89%). The total cognition of space loss was 61.11%. The cognitive degree of parents with different characteristics was different: the cognitive degree of parents over 50 years old was lower(14.29%), the cognitive degree of parents with higher education was higher(82.35%), there was no significant difference in cognitive degree among different gender, occupation and family monthly income groups. Parents paid more attention to the basic oral health of their children, most of the interval time between this visit and the last visit was 3 months(63.89%). The main purpose of the visit was caries or tooth pain caused by caries(63.89%). Most of parents did not know the harmful effect of space loss(72.22%). There were more parents who did not know the necessity of treatment to space loss(58.33%). Parents mainly learned the treatment to space loss through the doctor's education during dental visits(72.22%). The number of active visits were less when space loss occured(22.22%), and most of parents were recommended by dentist when they came to the clinics(72.22%). Most parents were able to accept the dentists' advice on the treatment of space loss(77.78%). CONCLUSIONS: It is necessary to strengthen the propaganda, coverage and depth of oral health education care, strengthen the awareness of oral preventive health care, especially for the parents with special personality on the importance of space loss, to prevent primary teeth caries and premature loss of primary teeth, avoid the loss of dental space, make the complete primary dentition to form a normal permanent dentition.

Key words: Space loss, Premature loss of primary teeth, Space management, Cognitive investigation