Assessment of Osstell™ and Periotest® systems in measuring dental implant stability (in vitro study).

Objectives: The objectives of this in vitro study were to investigate the sensitivity and reliability of the Osstell™ systems (Resonance Frequency Analysis - RFA) compared to the Periotest® system in implant bone simulated conditions. Three conditions were simulated: (1) the direct fixture-bone contact and fibrous tissue fixture contact, (2) The different levels of horizontal bone loss, and (3) The hardening implant-bone interface.

Materials And Methods: Forty-nine dental implant fixtures were placed in the center of acrylic cubes. In Part I seven fixtures were placed in direct contact with acrylic and another seven were placed in contact with polyvinyl siloxane impression material as soft interface. Part II: four sets of 0, 2, 4 and 6 mm horizontally exposed fixture samples were made (seven fixtures in each set). Part III: seven fixtures were placed in contact with a thin mix of autopolymerizing resin. The stability of these fixtures was measured using Osstell™ and Periotest® systems.

Results: The mean Periotest® value(PTV) and Osstell™ measurements showed a significant difference between the direct contact and soft interface (P < 0.001). These values also showed statistically significant difference between the different levels of horizontally exposed fixture groups (P < 0.001). The level of horizontal fixture exposure was strongly correlated with the PTVS (r = 0.967) and strongly negatively correlated with Implant Stability Quotient (r = -0.946). A strong correlation was found between the Osstell™ readings and the change in the stiffness of the autopolymerizing resin fixture interface group (r = 0.986).

Conclusions: Both Osstell™ and Periotest® systems proved to be sensitive in measuring dental implant stability in hard and in soft interfaces. Osstell™ also proved to be sensitive in detecting changes in the fixture interface stiffness. Osstell™ system proved to be more reliable compared to Periotest® system in measuring dental implant stability in hard and in soft interfaces.