Periodontometric and Periotest mobility parameters of 87 endosseous implants were studied during a period of up to 6 years. Moreover, the condition of the surrounding bone and mucosa was assessed by means of the Periodontal Index (PI). Mobility of endosseous implants was lowest during the first year of insertion and highest at the end of the study. Among all those variables that had a favorable effect on implant function, the length of the implants was in the first line. What is called the osseointegration of dental implants is no longer evident after just a short period of masticatory loading by a denture. Mobility parameters of implants then increase to those of periodontally healthy natural teeth. Improved dental hygiene and cleansing of the periimplant area reduce the incidence of pathological findings and improve the prognosis of dental implants.