The aim of the present cross-sectional study was to radiologically investigate the continuous eruption process in the deciduous dentition by assessing the difference in the width of radiologically-defined attached gingiva (RAG) in 6-year-old and 10-year-old children. The group of 6-year-olds had predominantly deciduous teeth and the 10-year-olds were in their mixed dentition period. The mucogingival junction was revealed with Schiller's iodine solution and marked mid-labially along the long axis of each tooth with a piece of metal wire prior to taking panoramic radiographs. The width of RAG over deciduous canines and molars was measured from the cementoenamel junction to the mucogingival junction. A significant increase in the width of RAG was found from 6 to 10 years of age.