Hi ...This is normal procedure that many dentist follow if decay is not very deep and is asymptomatic, as was in your case. Don't worry.Different dentist should have no problem doing filling in this particular tooth, but again that would b dentist's call.

Hello dear Please be advised I suggest you to please share pic and treatment details for confirmation of diagnosis. Thanks

We are in an exciting period of minimally invasive dentistry which enables us to use these amazing new materials that help us in remineralization instead of the old drill and fill concept. What protocol your dentist has followed is based on this concept, most likely he may have used either silver diamine fluoride/ GIC which arrests cavity without the need to drill and remove it. It also helps to save the tooth structure. If there's no pain then you have nothing to lose, if there is pain there's always another treatment option that can be planned. This is a conservative approach to treating tooth decay.