Peri-implantitis is a relatively new disease process that results in gingival in ammation and bone loss around implants. The associated co-morbidities are signi cant due to the relative nancial and biological costs of implant provision. At the current time there is a lack of consensus on the exact aetiology and subsequent pathological process, although this is largely thought to be infective in nature. Unfortunately, due to the relatively new nature of this problem, evidence is continually emerging

on diagnosis, prevention, prevalence and incidence. This rst part of three reviews will discuss these points and will act as an introduction to part two on prevention and part three on management of this now signi cant dental pathology.