Tooth implants are often problematic, not just due to their metal content but because they are a foreign piece of material that is drilled into your jaw bone - this can lead to tmj and other problems - they also affect energy flow in the particular meridian and can put stress on other organs (just like root canaled teeth).
If you don't have any issues currently with that root canal I would just have meridian stress assessment done on the tooth to see if its affecting your system in any way (although infection is most likely present). X-rays often don't show underlying infection - one of my root canaled tooth had beautiful X-rays and couldnt get my dentist and oral surgeon to remove it (because it looked good), but when my new dentist removed it, it had a large cyst of infection in one of the roots (about 0.5cm diameter) and horrible stench.
If down the road you decide to remove it, bridges are a better option compared to dental implants in my view.
Mike