Objective:The aim of this study is to evaluate clinical effects of early removal ofmaxillary mesiodens on reducingwidened di- astema of maxillary incisors in children.Methods:Totally 76 children with widened diastema of maxillary incisors were classified according to the aetiology of diastema. The mesiodens were removed, and patients were followed up for 3 years to investigate the changes of diastema.Results:The widened diastema of maxillary incisors in children was associated with central mesiodens (46P 47), as the rate of diastema in individuals with mesiodens was higher than thatwithout mesiodens (P