Good day
Usually a clinical exam would be advised in conjunction with an x-ray. An x-ray is only a 2-dimensional image, and although on an x-ray you can see the caries going into the pulp, the restorability and success of the root canal would better be judged in conjunction with a clinical exam.
With the Covid situation, it might call for some dentists to judge based on a x-ray alone, since they try and limit unnecessary patient contact in hot-spot areas.