Aim: To evaluate the performance of a three-dimensions (3D) imaging software (3D Slicer) developed for medical surgeons, in the 3D rendering of images of deciduous teeth made by CBCT. 3D Slicer is an open source platform for segmentation, registration and 3D visualization of medical imaging data. Slicer started as a research project between the Surgical Planning Lab (Harvard) and the CSAIL - Computer Science and Artificial Intelligence Laboratory (MIT). So far this software has never been used for evaluating root canal anatomy in dentistry and more specifically in paediatric dentistry. Therefore we wanted to explore its possibilities to clearly visualize the external root surface of deciduous teeth and the relative canal configuration in three-dimensions. Methods: Clinical CBCT images were used for the study, selecting scans previously taken for other purpose (e.g. impacted canines, odontoma) in which deciduous teeth were present. The CBCT scan had been obtained with the consent of the parents for the specific therapies. The age of young patients ranged from 6 to 14 years old . To use 3D slicer, some changes in the use and in the procedures had to be made. First import the DICOM file into software. Then crop volume for single tooth visualization, so do the segmentation selecting a satisfying threshold. Eventually edit the segment created for remove the aberration. Results: Results are shown by pictures, illustrating the possible achievement: root anatomy including resorption, root canal anatomy, intracanal navigation, measurements. In addition is possible export created surface in .stl file (stereo litography). With .stl file, for example students can navigate with a stl viewer application, even on their smartphone. Furthermore is possible with 3D printer make model that show root resorption and difference between anatomic apex and apical foramen. Conclusion: 3D rendering of deciduous teeth is an interesting diagnostic and teaching tools in pediatric dentistry. The available software, even though is not specifically developed for tooth rendering, it can be used for do this and excellent results can be achieved. However it must be underlined the fact that the suggested modifications are custom made and require computer skills and knowledge to be applied. Moreover they are time consuming. Therefore the hope is that in future new specific software for dentistry could be developed, to make 3d rendering more easy and rapid to perform.