TIMING OF LOADING AND EFFECT OF MICROMOTION ON BONE-DENTAL IMPLANT INTERFACE - REVIEW OF EXPERIMENTAL LITERATURE

A significant no-load healing period is the generally accepted prerequ isite for osseointegration in dental implantology. The aim of this art icle was to examine whether this no-load healing period is validated b y the experimental literature, In viva histological data was scrutiniz ed to identify the effect of early loading protocols on the bone-impla nt interface. Several Heading modes were identified. They were categor ized into groups according, to implant design and the type of prosthet ic reconstruction, and by their ability to introduce a distinct magnit ude of motion at the interface. Specific histologic responses of early loaded implants (i.e., fibrous repair or osseointegration) were sugge sted to be directly related to the specific combinations of the above parameters. Early loading per se was not found to be detrimental to os seointegration. Specifically, only excessive micromotion was directly implicated in the formation of fibrous encapsulation. The literature s uggests that there is a critical threshold of micromotion above which fibrous encapsulation prevails over osseointegration. This critical le vel, however, was not zero micromotion as generally interpreted. Inste ad, the tolerated micromotion threshold was found to lie somewhere bet ween 50 and 150 mu m. Suggestions are made for the earliest loading ti me that achieves osseointegration. (C) 1998 John Wiley & Sons, Inc.