ObjectiveThis study aimed to measure the taper and diameter of root canal, as well as the elastic modulus and hardness in the root dentin of maxillary primary anterior teeth.MethodsPatients under general anesthesia who needed root canal therapy in the maxillary primary anterior teeth were selected. Silicone impression material was used to take impressions. The impressions were scanned, and the taper and diameter of root canal were measured. Maxillary primary anterior teeth were collectedin vitro. The elastic modulus and hardness of root dentin was tested.ResultsA total of 74 silicone impressions were obtained. The mean tapers of primary incisor teeth, primary lateral incisor teeth, and primary canine teeth were 0.106, 0.185, and 0.098, respectively. The mean diameters of the root canal 5 mm below the cementum-enamel junction (CEJ) were 1.267, 0.860, and 1.429 mm, respectively. The elastic modulus and hardness of root dentin were measured in 10 primary anterior teethin vitro. The range of elastic modulus was 19.919-25.017 GPa. The range of hardness was 0.867-1.082 GPa.ConclusionThe root canal post used in primary anterior teeth can be produced by the following data: taper of primary incisor teeth and primary canine teeth, 0.1; diameters of their tips, 1.2 mm and 1.4 mm, respectively; taper of primary lateral incisor teeth, 0.2; diameter of their tips, 0.8 mm; range of elastic modulus, 20-25 GPa; and range of hardness, 0.87-1.08 GPa.