Determination of the success and failure of root-form osseointegrated dental implants

Permucosal osseointegrated dental implants are a highly effective and predictable treatment modality for edentulism. This review discusses some controversial aspects of the definitions for success and failure of root-form dental implants. The discussion will focus on the underlying pathologies that, if untreated, may lead to loss of the implanted device. Few clinical syndromes are described based on human pathological material and clinical presentation. The theoretical chronological relationship between implant loss and the incidence of pathology of the soft- and hard-tissue seal around implants is also discussed. The review also examines the finding that implant failures are not randomly distributed in the treated populations and that implant loss clusters in specific high-risk groups and individuals. Known risk indicators, and possible risk factors, are discussed, taking into account the patient, the reconstruction, the implant, and implant site-specific factors. Particular emphasis is placed on the need for better determination of whether periodontal patients are at higher risk for implant failures as a consequence of their increased susceptibility to infectious, inflammatory-response-driven tissue breakdown.