Finite element and experimental analysis to select patient's bone condition specific porous dental implant, fabricated using additive manufacturing

Background: Differences in patients' bone conditions lead to variations in the bio-mechanical environment at the peri-implant bone after implantation. It is therefore imperative to design patient-specific dental implants with customized stiffness to minimize stress shielding and better osseointegration. Method: Nine Ti-6Al-4V implants with pore sizes of 500, 700, 900 mu m and 10, 20, 30% porosity each and one non-porous (solid) implant were modelled for experimental and finite element (FE) analysis. Using computed tomography (CT) data of the mandible, five different bone conditions were considered by varying bone density. Implants were fabricated using additive manufacturing, and micro-CT analysis was performed for assessing accuracy of fabricated implants and further modelling for FE analyses. The FE results were also compared with experimental results. Results: Under a 200 N static load, the average difference between the experimental and FE observations of deformation was 9.7%. The peri-implant bone micro-strain revealed statistically significant interactions between percentage porosity (%porosity) and bone condition, as well as between pore size and %porosity (p 0.05). In contrast, no statistically significant interaction between pore size and bone condition (p 0.05) was observed. Together, %porosity and bone conditions contributed about 45.22% of the overall peri-implant bone micro strain. Conclusions: Considering 1500-2000 as the maximum generated peri-implant bone micro-strain during regular physiological functioning, implants with 700 and 900 mu m pore size and 10% porosity were deemed suitable for a 'very weak' bone condition. Contrarily, implants with 900 mu m pore size and 30% porosity generated the highest peri-implant bone micro-strain for a 'normal' bone condition. Overall, the study establishes the necessity for considering the patient's bone condition as an important factor for the design of dental implants.