Could a dentist answer this question please?

Is it possible to have a painless abscess under a tooth where the nerve is still alive, or does this only happen if the root has died?

Is an abscess visible on an xray? Does the tooth have to be decayed before an abscess forms? I've had the tooth xrayed......it doesn't ache. Would an abscess have showed up at that stage? There was infection around the tooth and an abscess on the gum next to that particular tooth. The infection was cleared up with antibiotics and a dental clean. The gum abscess has healed, but the tooth throbs slightly, especially after cleaning my teeth and when I'm lying in bed. The dental work was done about a month ago. The tooth is also slightly sensitive if I tap it with something metal. I have a digestive problem that is acting up and I need to eliminate any dental problems asap. I would appreciate anymore input. Thanks.

Yes, it is possible in some instances, like if the abscess is draining. The reason there is no pain is because the source of the infection is draining; no pressure inside the root to buildup and cause pain. If the abscess isn't draining, and you have no pain, that indicates that the nerve in the root is dead. If you do have draining, your root could still be alive. Regardless, in both situations, you will need to have a root canal done , since once a root is infected, there is no other way to relieve the infection. Your tooth can't heal itself when the decay has extended that far