[Effect of implant geometry on strain distribution in peri-implant bone]

Recent developments and results in the field of mechanical bone stimulation have made it possible to define limits between physiological and non-physiological transmission of strength to the bone. Now it is necessary to investigate the different geometries of dental implants regarding biomechanical reliability. The aim of this study was to examine the distribution of strain on the bone along different basic forms of implants during loading using finite element analysis (FEA). The following implant designs were included in the study: cylinder, threaded cylinder, cylinder with steps, threaded cylinder with steps, and double-disk implants. All implants had a length of 12 mm and a diameter of 4 mm, the axial loading was defined as 300 N. Threaded implants showed more homogeneous distribution of strain than stepped implants, however, the maximum values were below the physiological range. Shortening of the implants led to an increase of the values, however, there was a zone of hypophysiological strain apically. Disk implants showed extremely low values at the disk margins, possibly due to the lack of physiological bone stimulus by the disks. Overall, none of the implants showed optimal distribution of strain, even though homogeneous strain distribution is decisive for long-term implant stability.