Abstract: 0bjective To investigate the prevalence and distribution of teeth number abnormalities in school-age children at the mixed dentition stage by performing panoramic radiographs analysis．Methods A total of 3432 panoramic radiographs of pediatric patients aged 5 years to 12 years who were admitted to the hospitals from January 2013 to June 2017 were reviewed．The presence of teeth number abnormalities were recorded as follow：congenitally absent teeth，supernumerary teeth，odontoma. SPSS 13.0 software was used for statistical analysis．Results The prevalence of teeth number abnormalities in pediatric patients’permanent teeth was 25.52%. The prevalence was higher in males. Significant difference between the genders was observed（P<0.05）．Tooth agenesis，the most frequent dental anomaly（13.43%），was considerably common in females；supernumerary teeth(11.74%)followed，which was significantly common in males．Both differences were statistically significant（P<0.05）．The prevalence of odontoma was 0.35%. Conclusion The prevalence of teeth morphology abnormalities in children’s permanent teeth at the mixed dentition stage is apparently high. Panoramic radiograph is an efficient method for the early diagnosis of teeth number abnormalities．

Key words: mixed dentition, dental anomalies, panoramic radiograph, School-age children