Do Dental Implants Ever Fail?
Dental implant treatment is one of the most successful procedures in the medical-dental field, with documented success rates over 95%. Although successful treatment is very predictable, there are rare occasions where the bone does not completely bond to the implants. When this occurs, new implants are placed, and the success rates for the replacement implants are even higher.

There is no guarantee in any dental implant procedure.
There are patients factors as well as dentist factors.
but, implants has been reported to last until 30 years in the mouth.
Try this article, its most FAQ on dental implants.
http://www.intelligentdental.com/2010/03/19/most-asked-questions-on-dental-implants-part-2/
Unfortunately, they do. However, it’s mostly due to patient neglect in their home care. I’ve found implants to be better than real teeth. They don’t decay and if properly cared for, seem to last forever. If you smoke however, forget about them!
Doesnt *everything* fail at some point or another?