Dentist here...this is not advice, just a general comment. Implants are incredibly safe and by far the best method of tooth replacement compared to something like a partial denture or bridge. Teeth that have had root canals and crowns will ALWAYS need future work. It might be 5 or 10 or +20 years but they will always need more treatment and crowns and root canals fail far more often than implants. Root canals fail because the root canal system becomes infected again and crowns fail because cavities start adjacent to the crown margin and start to undermine the crown. Really the only issue with implants is if it fails to integrate into the bone and that's rare, and it usually just means removing the implant, letting the hole heal, and trying again. Once it is integrated into the bone, you're usually good to go. Titanium is incredibly biocompatible, it undergoes osteointegration (fuses to the bone), and it's really an ideal implant material.