Sunday, November 1, 2009
Periotest M: Measurement of Dental Implant Osseointegration
Periotest M: The Periotest M is a measuring device for use in dental practices and is designed for the following range of applications:
- Implants: Assessment of the osseointegration of dental implants
- Natural teeth: Diagnosis and assessment of periodontopathies,
assessment of the occlusal load and control of the treatment’s progress
The Periotest’s scale ranges from -8 to +50. The lower the Periotest value, the higher is the stability / damping effect of the test object (tooth or implant).
Assessment of the osseointegration of dental implants
Nowadays there are many implant systems which are in use. The Periotest M unit is able to take measurements on all of them. Moreover, measurements can be made at all stages of the implant process: directly after implantation, to measure primary stability, following the healing phase to determine that the required degree of osseointegration has taken place to enable pressure to be applied to the implant, and following completion of the prosthetic, to enable any negative developments to be recognised at an early stage.
As a result of the different implant systems and the existence of varying clinical conditions with individual patients, it is only possible to present guide values here. These show which Periotest value indicate good osseointegration and which are insufficient for withstanding pressure on the implant.
Periotest Value Range Interpretation
-8 to 0 Good osseointegration; the implant is well integrated and pressure can be applied to it
+1 to +9 A clinical examination is required: the application of pressure on the implant is generally not (yet) possible
+10 to +50 Osseointegration is insufficient and no pressure may be allowed to act on the implant
On the whole, implants lose a certain amount of stability in the first 14 days following implantation, and this is reflected by an increase in the Periotest values of one to two units. However, once the healing phase is over, the Periotest values obtained will be similar to those immediately following implantation (primary stability). Significantly greater increases in Periotest values, even a number of years after implantation, are an indication that the implant has become unstable, one of its screws has loosened, or it has excess pressure or has become infected (e.g. periimplantitis). It is therefore advisable to record all measurements to allow monitoring checks to be conducted over time.
The Periotest measuring procedure is electromechanical. An electrically driven and electronically monitored tapping head percusses the test object (tooth or implant) 16 times. The entire measuring procedure requires approx. 4 seconds. The tapping head is pressure sensitive and records the duration of contact with the test object. Loose teeth or implants display a longer contact time and the Periotest values are correspondingly higher, while sturdy teeth or well osseointegrated implants have a short contact time and result in low Periotest values.
To ensure that the measurement is valid and meaningful, it is important to ensure that the handpiece is positioned correctly with respect to the test object (distance, angle). The device itself provides assistance by monitoring all 16 impulses. Incorrect impulses are eliminated to ensure reliable and reproducible measurements.