As a thumb rule if you have done a RCT. You must cap the tooth immediately as soon as possible or else the tooth will crumble and break. Different varieties of crowns are available depending on the quality and price.

Hello, The colour change in the root canal treated tooth is because the tooth becomes non vital once the infected nerves(pulp) of the tooth is taken out in the root canal treatment procedure, and thats very normal as there is no nutrient supply to the tooth, it becomes darker from normal with time. Root canal treated tooth also becomes brittle and tend to break with time, hence it is advised that after RCT once the tooth becomes asymtomatic and patient doesnt feel any discomfort, go for crown. There are several types of crowns available, you can choose one according to your need and budget.