I was recently diagnosed with idiopathic root reabsorption on one of my lower molars.
"Common Symptoms: Resorption is typically asymptomatic and progresses slowly, making routine dental check-ups vital. When symptoms do appear, they often include: Pinkish spots or a pink tint on the surface of the tooth.Unexplained radiating tooth pain."
*This is what happened with me. I had some discomfort and then upon closer inspection my dentist noticed a very small pink area and referred me to an endodontist.
The endodontist wasn't sure if the tooth could be salvaged and he referred me to a periodontist. He said he had only seen one other case similar to mine during his entire career. They classified mine as idiopathic in which they don't really know what caused the condition. 3D imaging was done of that specific tooth.
It was never really discussed whether it was internal or external in my case, so I don't really know. I was presented with the option of either doing a root canal or getting an extraction. The extraction was strongly advised because they had low confidence that a root canal would work for the long-term and if I was going to spend that amount of money it would be better spent toward the permanent solution of an implant.
A bridge/denture was another option and would have been less expensive but is an inferior solution in the long run for multiple reasons. I could have also just have not done anything after the extraction but I didn't want to leave a hole there for the rest of my life and then also experience the inevitable bone loss that occurs in that part of the jaw bone. It can have negative clinical and aesthetic consequences over time.
After thousands of dollars and many months of the multi-step implant process, I am now rocking a dental implant. It was completed September of last year. Of course every case is going to be different. Apparently, mine was a little too far gone when it was discovered to reasonably save the tooth even though I am meticulous with my dental care and in having cleaning/exams every 6 months.