To fill a hole drilled in a dental bridge for a root canal, Should filling material make it look like the hole was never there?

Ideally, it should be masked completely but due to the difference in material sometimes it is visible. It does not affect the function of the restoration but if you do not like the look of it, please discuss it with your dentist as he will be able to restore it according to your wishes.

The goal is to mask it, however it is not always possible due to the metal frame under the porcelain. However, if it an all percelain bridge, it makes it easier.

What material was used for your bridge? porcelain stacked on metal? all ceramic (emax or zirconium)? If you see grey most likely the metal underneath is showing through the resin restoration. you can block out the metal with some very opaque flowable resins. you then use a more natural shading system to match the ceramics. It is not uncommon to see the access but is the time involved and extra cost worth it? does the access show when you smile or speak? make your concerns known to the the treating dds and see what options can be done to make the end result more esthetic