Although many companies make dental implants, they all are very similar. They are conical in shape and have threads for srewing into bone. Until recently they were all made from titanium. Now there is a ceramic (nonmetal) implant available in the United States. Historically the first dental implants were titanium. Then they changed the materials and the sprayed all sorts of surface coatings on them to make them work better. However, nothing worked as good as the original recipe so the manufacturers went back to commercially pure titanium again.
Titanium is a very reactive metal but not when it has an oxide layer covering its outer surface. Titanium only exists with this oxide layer when exposed to air. This oxide layer is what makes titanium such a biocompatible material. The bone and body tissues do not recognize it as a foreign body and bond directly to it. The titanium oxide layer is also anti-inflammatory. Titanium does not corrode in contact with body fluids. Galvanic corrosion can occur if a crown made of dissimilar metal is cemented on a titanium implant. The crowns that we use in our practice are all nonmetal crowns so galvanic corrosion cannot occur.
(No one can claim that any dental material is not biocompatible just because it contains certain ingredients (again, just considering general and immunological biocompatibility here). The initial ingredients do not determine the compatibility of a dental material. The corrosive by-products (which are chemically different from the original chemical structure of a material) and the corrosion rate (or half life) are the most important information in determining whether a dental material is compatible or not. If a material remains chemically intact and does not break down on a molecular level to any consequential degree, it cannot harm you. The corrosive by-products (if not compatible) have to be bio-available to the cells in enough quantity to cause a problem for your body.)