I practiced pediatric dentistry for 30+ years in my private office, now semi-retired I work locum tenens. About the only experience I have with your type of problem is my own situation. First, what is the problem with the tooth? Does it have a large cavity, or an old large restoration, or a periodontal (gum) problem, or has the tooth given up to years of service and split, or cracked. If it has an old restoration, is it a gold restoration, silver restoration, or composite (plastic)? These are the things I would look at before deciding how to treat your situation. In my case, I had two upper molars, one on each side, that had cracked vertically, involving the root. I had root canal therapy on the first, and it failed after several years. I had a implant placed with a crown and it is vey acceptable. Several years later the other molar had the same problem, and I consulted a different endodontist about root canal therapy. He did not think this one would be treatable, so I had another extraction and implant placed. I am very happy with the implants, but it is not inexpensive. If you happen to have a copy of your X-ray, I would be happy to look at it and give you my opinion. If you are able to copy it on your computer, please send me a PM. Good luck.