Assessment of implant stability using a novel percussion measurement device 

Method: Polyurethane bone blocks (Sawbones) with various composition and densities including, solid rigid with 0.48 g/cm^{3 (}(group A); cellular rigid with 0.20 g/cm^{3 (}group B), and cellular rigid with 0.12 g/cm³ (group C) were used to simulate human cortical and cancellous bone in vitro. Straumann^® (10mm,ø3.3mm) implants were inserted into the sites prepared by an undersized technique. Implant stability was assessed by tapping the implant before and after torqueing the prosthetic abutment, by 3 investigators taking 5 readings with IMS and Periotest (PT) devices. Inter & Intra class correlation analyses for repeated measurements were performed to assess reliability of both devices. Pearson correlation analyses were performed on the initial placement torque (primary stability) and devices’ quotients.

 Result: There were strong correlation between investigators (r=.85) and repeated measurements (0.75) when IMS device was used.  More fluctuations of values and weaker correlations noted for the Periotest. Both devices indicated that a block with the greatest density (group A) provided the highest implant stability. The primary stabilities (IMS and PT) values before abutment placement were 79±0.3 and -4±1 for group A, 72±0.4 and 7.4±0.8 for group B, and 64±0.5 and 14±2 for group C, respectively. While, the primary stabilities (IMS and PT) values after abutment placement were 61±0.5 and 8±3 for group A, 40±0.8 and 31±0.7 for group B, and 32.6±0.8 and 41.8±4 for group C, respectively.

Conclusion: This in vitro study demonstrated that IMS is a highly reliable device for measuring dental implant stability. The study showed comparable results for both devices in relation to change in bone density.