Abstract
This article shows the factors of importance in the long-term success and failure of oral implants based on literature review. Many factors are attributed to the failure of dental implants. The critical components leading to early and late implant failures are evaluated. The behavior of natural teeth and implants is compared in healthy and unfavorable local and systemic conditions. Similarities and differences among dental implants, healthy natural teeth, and ankylosed teeth are examined. Based on this comparison, the author attempts to draw a conclusion on the vulnerability of dental implants and their prognosis. The importance of ongoing clinical supervision of a patient's implant condition with a good recall program and the necessity to accumulate clinical data concerning implant failures over an extended period of time in a standardized manner are emphasized. It is also suggested that implant practitioners avoid giving guarantees of long-term implant success to their patients.