RELATIONSHIP BETWEEN CONTACT TIME MEASUREMENTS AND PTV VALUES WHEN USING THE PERIOTEST TO MEASURE IMPLANT STABILITY

Purpose: The Periotest is an electronic instrument that has been advoc ated for the measurement of implant stability and osseointegration. Th e aims of this investigation were to establish the relationship betwee n contact time and PTV values when the Periotest was used to assess im plants in vivo and in vitro, and to investigate the influence of the s triking height of the Periotest handpiece and the length of implant ab utment. Materials and Methods: The accelerometer signal from a Periote st was captured and compared with the resulting PTV value. In vitro me asurements of PTV and contact time were performed on a 3-mm abutment t hat had been attached to a 15-mm implant luted into an aluminium block , and were repeated on a patient in vivo. Further measurements were ma de of the abutments of six implants in turn in the maxilla of the same patient. The standard abutment lengths on the implants were 3, 4 (x 2 ), 5.5 (x 2), and 7 mm. Results: The results indicated that there was a linear relationship between contact rime and PTV value for implants measured in vitro and in vivo. Greater scatter of the in vivo data was attributed to test and patient variables including striking position, distance, and damping as a result of the presence of soft tissues. Th ere was a linear relationship between the PTV value and the striking h eight for implant measurements in vivo and in vitro. Conclusion: It ca n be concluded that the sensitivity of the Periotest to clinical varia bles including striking height and handpiece angulation limit the appl ication of the instrument as a clinical diagnostic aid to measure impl ant stability.