Dental implants are titanium fixtures which are inserted into the jawbone to replace missing single/multiple teeth. Most modern implants are made from titanium which is an extremely safe and biocompatible metal with little reported complications although best avoided if you have a metal allergy. They are extremely strong, flexible and have been proven long term. Titanium is used extensively for other medical procedures too such as hip and knee replacements.
Newer dental implant materials include zirconia ceramic implants which are white in colour and although are gaining in popularity are not as commonly placed as titanium. There are concerns with ceramic implants fracturing although zirconia is an extremely strong material and there is little evidence for long term follow up. They can be a great aesthetic alternative in the front of the mouth due to no metal show. There are also some studies which show greater bone loss and less survival rates compared to titanium.
Dental implant placement requires a great degree of skill and planning, respecting the surrounding anatomy and vital structures in addition to following sound evidence based biological protocols. If all this is taken into consideration then placement of dental implants is a very safe and predictable procedure.