Engineering Science and Technology, an International Journal (May 2023)
Investigation of subcrestally placed dental implants with and without apical cortical bone anchorage under conventional or immediate loading
Abstract
There is no firm evidence regarding the effect of apical cortical bone anchorage of subcrestally placed dental implants in terms of the stress and strain distribution in the peri-implant bone, implant and prosthetic components and in terms of the micromotion of the implant. The purpose of this study was to form an estimate of the effect of different apical bone anchorages of subcrestally placed implants on the stress and strain values of peri-implant bone, implant and prosthetic components and micromotion of the implants by making use of three-dimensional (3D) finite element analysis (FEA). Six 3D FEA models with different apical bone anchorages and different implant loading protocols were created. Both the von Mises stress values for implant and prosthetic components and the maximum (tensile) principal stresses (TPS) and minimum (compressive) principal stresses (CPS) and principal elastic strain (PES) values in peri-implant bone were obtained. Additionally, micromotion values in the implants were analyzed. In subcrestally placed implants, it is observed that providing apical cortical anchorage diminishes the average values of TPS and CPS in the trabecular bone (TPS oblique M2A-0.63 MPa, TPS oblique M3A-0.58 MPa; CPS oblique M2A-0.82 MPa, CPS oblique M3A-0.65 MPa; TPS axial M2A-0.37 MPa, TPS axial M3A-0.14 MPa; CPS axial M2A-0.78 MPa, CPS axial M3A-0.30 MPa). Similarly, it is seen that the apical cortical anchorage diminishes the maximum and minimum PES values in the trabecular bone in subcrestally placed implants (min PES oblique M2A-15542 µɛ, min PES oblique M3A-14334 µɛ; max PES oblique M2A-9607 µɛ, max PES oblique M3A-8850 µɛ; min PES axial M2A-5156 µɛ, min PES axial M3A-2206 µɛ; max PES axial M2A-4487 µɛ, max PES axial M3A-3096 µɛ). It was also found that apical cortical bone anchorage is advantageous in terms of micromotion in the subcrestally placed implant (trabecular bone-implant (4th) micromotion values: oblique M2A-3.23 μm, oblique M3A-2.36 μm; axial M2A-0.96 μm, axial M3A-0.49 μm; trabecular bone-implant (6th) micromotion values: oblique M2A-3.45 μm, oblique M3A-2.72 μm; axial M2A-1.32 μm, axial M3A-0.59 μm). The present study demonstrated that apical cortical bone anchorage in subcrestally placed implants provided more favorable values of stress and strain in the peri-implant bone and reduced the micromotion of the implant.
