For years Grade 4 commercially pure titanium has been the material of choice for dental implants. There is plenty of long term data demonstrating safety and success.
More recently some manufacturers have been switching over to Grade 5 titanium. Titanium Grade 5 is alloyed with 6% Aluminum and 4% Vanadium and is commonly known as Ti 6Al-4V. For dentistry, there is another version called “ELI”, extra low interstitials, which further reduces surface impurities. Grade 5 titanium is said to be stronger than Grade 4. However there is evidence that Vanadium is released into the host tissues and can be cytotoxic.
A recent literature review concluded that there is not enough evidence indicating superiority of one vs the other, noting specifically that good clinical comparison studies do not exist.
I have made inquiries to implant manufacturers asking for long term safety data in humans, and so far I have received nothing decisive. Hmmm…