Q. I have a post and crown on a front tooth that I’ve had for some 20 years. I’m currently experiencing some discomfort and sensitivity in the tooth although I’m told by my dentist that there is no nerve there. I’ve been referred to a specialist who suggests that there is bacteria in the root canal, and I need minor surgery to clean it up (at £500). The specialist says there is nothing to see on the X-ray, but this is the most likely cause. He says surgery is better than removing and replacing the crown and post, as they’re a very good fit (although not a particularly good match for my other teeth. I have three questions: (1) does this sound like good advice from my specialist? (2) What other possibilities are there if his diagnosis is wrong? (3) I’m concerned that the problem will recur after surgery. I’m in my late 40s and my gums are receding. I guess the problem has occurred because there are gaps in the seal between post and gum. Thanks very much