There is an increasing awareness that, for clinical monitoring of oral implants, there is a need for reliable diagnostics and possibly prognostic parameters. Indeed, reports have too often limited results to an inventory of failures, while no mention was made of progressive marginal bone loss or other symptoms of a future failure. Several parameters, such as marginal bone level assessment and/or probing attachment level, give a precision of up to 0.5 mm. Both measurements also seem related. The damping characteristics of the individual implant/bone unit also offer a highly reproducible diagnostic tool. The Periotest allows for detection of subclinical mobilities, and 95% of repeated measurements fall within a range of one unit on the arbitrary scale. So far, these three parameters offer no prognostic value.