Relation between bone quality values from ultrasound transmission velocity and implant stability parameters - an ex vivo study

Aim The objective of this study was to determine the relationship between bone qualities measured by ultrasound transmission velocity (UTV) and primary implant stability parameters measured by radiofrequency analysis (RFA) and push-out test (POT) in an ex-vivo model. Materials and methods Three blocks of fresh porcine bone samples were obtained from different anatomic regions, correlating to cortical, mixed and cancellous bone. Mechanical bone qualities of these samples were measured using UTV (expressed in m/s) prior to implantation. Three similar implants (4.1 \x \11 \mm, AstraTech OS) were inserted into each of the procured bone blocks. The evaluation of implant-bone interface stability was evaluated by RFA expressed as implant stability quotient (ISQ), and POT measured in Newton (N). Results For cortical, mixed and cancellous bone samples UTV values showed a mean of 2049.33, 1728.67 and 1427.67 \m/s, respectively. For the implants inserted into cortical, mixed and cancellous bone samples the mean RFA (ISQ) values were 94.33, 81.33 and 63.11, whereas the POT values were >2000, 680 and 290 \N, respectively. There was a strong correlation between UTV values and implant stability parameters that was shown descriptively by scatter box plots. Conclusion The bone quality measurements obtained by UTV values significantly correlated to primary implant stability values measured by RFA and push-out test. Moreover, UTV was able to significantly differentiate between the different bone types. This suggested that UTV may be considered as a reasonable instrument to measure bone quality preoperatively and would help clinicians predict primary implant stability before implant insertion.