Hi, I Have a divitalised molar, with a crown ontop. A few months ago I Got a small pimple on the gum by the crown, this comes and goes, but no pain. the dentist noticed some infection under the tooth, but its firm and not wobbly. He thinks extraction is better as recleaning the root canal will be costly and may not last long or solve the problem. I think its best to cure existing tooth under the crown. as it may Have Got a little unsealed and therefore needs resealing. what is the best advice?