Assessment of implant stability by resonant frequency analysis.

The hardness of compact bone is about 10 times higher than cancellous (trabecular) bone, thanks to both its density and mineralization. The higher bone density gives the higher primary implants stability values . Considering that cancellous bone has lower biomechanical values, some authors like to name it ‘lower quality bone’, which is not quite exact and correct term. It is better to name it – ‘low density bone’. The most important parameter is the quality of bone that can be classified by its density based on panoramic radiography . Bone is then classified as: type 1 – compact bone; type 2 – thick layer of compact bone which overlays trabecular bone; type 3 – thin layer of cortical bone which overlays dense trabecular bone; type 4 – thin layer of cortical bone which overlays low density trabecular bone (Figure 1). Regardless bone density, particular concern should be carried out with patients at risk, like patients after radiotherapy 15, . Implant stability can also be differentiated by the location in the jaw bone region. Higher values of primary stability are achieved in the regions with higher bone density (measured by computed tomography – CT), such are intercanine and molar regions. In case of higher bone density, a high value of primary stability will be achieved 17, . Fig.1 – Bone type scheme, drawn by Dr. Filip Ivanjac, inspired by Lekholm and Zarb .