Relationship Between Primary/Mechanical and Secondary/Biological Implant Stability

This systematic review was prepared as part of the Academy of Osseointegration (AO) 2018 Summit, held August 8-10 in Oak Brook Hills, Illinois, to assess the relationship between the primary (mechanical) and secondary (biological) implant stability.Electronic and manual searches were conducted by two independent examiners in order to address the following issues. Meta-regression analyses explored the relationship between primary stability, as measured by insertion torque (IT) and implant stability quotient (ISQ), and secondary stability, by means of survival and peri-implant marginal bone loss (MBL).Overall, 37 articles were included for quantitative assessment. Of these, 17 reported on implant stability using only resonance frequncy analysis (RFA), 11 used only IT data, 7 used a combination of RFA and IT, and 2 used only the Periotest. The following findings were reached: ·Relationship between primary and secondary implant stability: Strong positive statistically significant relationship (P < .001). ·Relationship between primary stability by means of ISQ and implant survival: No statistically significant relationship (P = .4). ·Relationship between IT and implant survival: No statistically significant relationship (P = .2). ·Relationship between primary stability by means of ISQ unit and MBL: No statistically significant relationship (P = .9). ·Relationship between IT and MBL: Positive statistically significant relationship (P = .02). ·Accuracy of methods and devices to assess implant stability: Insufficient data to address this issue.Data suggest that primary/mechanical stability leads to more efficient achievement of secondary/biological stability, but the achievement of high primary stability might be detrimental for bone level stability. While current methods/devices for tracking implant stability over time can be clinically useful, a robust connection between existing stability metrics with implant survival remains inconclusive.