Overview of clinical trials on endosseous implants

Early history of clinical trials on endosseous implants revolved around anecdotal reports on predominantly blade implants in the U.S. The first criteria to define success or failure were established at the National Institutes of Health (NIH)-Harvard Conference in 1978. This was followed by the multi-center trials from the Branemark group which described round, metallic implants. At the 1988 NIH Conference, questions dealt with the following: 1) the effectiveness of dental implants for the long-term; 2) indications and contra-indications of various types of implants; 3) requirements for management of dental implants; 4) health risks of dental implants; and 5) future directions in research. In the ensuing 7 years since the second NIH Conference, most of the data generated have been from non-controlled case reports, which describe a 90% success rate in 5 years or more with many types of endosteal systems in both partially and fully edentulous patients. Therefore, it can be said that there is evidence that dental implants are effective for the long-term. The other questions posed at the 1988 NIH Conference have not been as well described and have led to many controversies and future research areas. Two areas which will have a special future impact are 1) the establishment of a standard of care and risk-benefit ratio for implants and 2) the use of various factors to accelerate bone formation to allow greater access to dental implants by patients.