Advice on Suggested Dental Crown Replacement with Implant?

You have described a pretty typical problem that I see in my dental practice frequently. You have a front tooth that needed a root canal and crown. A front tooth with a root canal should also have a post placed in the tooth. The post act like rebar to reenforce the tooth and minimize the risk of tooth fracture. Unfortunately, posts also present inherent risks including root fracture and displacement of the post. 

Most of the time when a crown as you described is "loose" it means that the post has debonded from the tooth. If the post and crown only lasted six years then doing a new post and crown would probably not last any longer. Therefore, the suggestion to take the tooth out and replace it with an implant and crown is not a bad idea since we know the implant will last indefinitely. Sometimes it makes no sense to continue investing in a tooth that doesn't have a good long-term prognosis. 

If I can't honestly tell my patient that a restoration will last a long time I am extremely reluctant to offer it as a viable option. There are almost always multiple ways to fix a dental problem; in your case, a dental implant and crown could well be your best treatment option.

Good luck!

It's usually best to keep your natural teeth as long as possible. Sometimes however, teeth are so badly broken down or have such a bad crown/root ratio that it doesn't make much sense to keep them. An implant could be the least expensive and most reliable option for you long term. Today, implants have a very high success rate and it's often better and less expensive to have a successful implant rather than complicated dentistry on questionable teeth.

If you have a crown that  no longer has a favorable or reliable prognosis due to a compromised tooth structure than an Implant would be the ideal replacement.  There are times when an existing crown might have recurrent cavity and what remains under the old crown is limited.   Another possibility could be a poor ratio of crown to root.  This means that the remaining support of the root by the bone is limited.  Cases like this tend to happen if there is a periodontal (gum) issue over time where bone is gradually  lost. The replacement of the tooth by an implant is the way to go and this can be done with great success.