Diagnosis, treatment planning, and treatment monitoring in endodontics depend to a very large extent on results from radiographic examinations. The often complex anatomy in respect to the teeth themselves as well as their surrounding structures may render those tasks difficult. New tomographic techniques hold promises for improvements in all those areas, in particular techniques that can display the object in all its three dimensions and remove disturbing anatomical structures to make it possible to evaluate each root and its closest surroundings in detail. They also provide images, taken at different points in time, that are similar in geometry and contrast making it possible to evaluate differences occurring in the fourth dimension – time. Image-processing techniques applied to digital images obtained with conventional periapical radiography can be of some help towards improved diagnosis provided that optimal irradiation geometry has been used during image acquisition. When conventional radiographs are used and conventional means employed for their evaluation, one should take radiographs from more than one direction to ensure that at least some three-dimensional information will be obtained. When evaluating images over time they must be compared side by side to provide best possibilities of subjectively detecting changes occurring over time.