When a tooth "dies", the nerves and/or roots break down and things can get yucky. Been there, done that. In my case, I developed a cyst in my mouth and the oral surgeon had to cut the gum, peel it back, scrape out the cyst, and sew the gum back into place, while I remained conscious. I was amazed that I could sit through the entire procedure, which was followed up with a root canal and a crown by my dentist. The teeth closer to the front of your mouth are rather thin (unlike molars), so a root canal further weakens the tooth. After performing the root canal, the dentist will often grind the tooth down to a point where it is wider, insert a post, and add a crown. The crown should be as strong as the original tooth was, while a veneer is a cosmetic thing with less strength. It would be a shame to get a veneer and have it break later on. I'm not an expert, just an educated survivor. Your best answer should come from a true professional. Some people may claim to be pros, but you shouldn't trust the 'net that much...even if they really are pros, because it's difficult to confirm that they really are.