The use and abuse of the Periotest for 2-piece implant/abutment systems

While the Periotest continues to be used in assessing the integrity of impl ants, there are numerous reports of its inconsistencies. To understand more precisely what the Periotest is actually measuring, a mathematical model w as developed that illustrates the effect that various geometric and clinica l parameters have on the Periotest value (PTV). In addition, the model was validated with an in vitro experiment. Results of the mathematical model ar e shown to correlate with those obtained from the experimental test. The PT V is very sensitive to the position at which the Periotest impacts the abut ment and to angulation of the handpiece. It was shown that a change in posi tion of 1 mm in striking height can produce a difference in PTV of between 1 and 2. Since the angulation of the handpiece can produce a difference in striking position of 2 mm, it must be controlled as well. The model also sh owed that the Periotest can detect changes in bone height of 0.5 mm.