A biomechanical assessment of dental implant stability under the effect of changes in bone remodeling factors and implant elastic modulus.

BACKGROUND AND OBJECTIVE: The simulation of the biological phenomena can assist physicians in development of the advanced therapeutic plans and methods based on the computer model results and engineering analysis. The application of these models can predict and evaluate the medical experiment output by removing the barriers of technical and practical limitations, and expensive laboratory equipment. This provides the scholars with the preview and insight to design practical experiments and save cost, energy, and time. The present study aimed to provide a calculational, finite element-based simulation of the mandible bone's remodeling under the osteoporosis condition to quantify and evaluate the stability of a dental implant using the indicator implant stability quotient (ISQ). The effects of the significant chemical factors involved in bone remodeling including osteoprotegerin (OPG), transforming growth factor beta (TGF-beta), and the parathyroid hormone (PTH) as well as the effect of the implant's elastic modulus were also included in the model. The literature lacks a predictive combinatory model considering the comparative effects of these chemicals on the implant stability which was addressed by this study. METHODS: A 3D geometry of the mandible portion assembled with a Straumann implant geometry was developed using a CT image dataset. The model geometries were imported to finite element software for the definition of the material properties, boundary conditions, constraints, and mathematical relations. The model's basic parameters were based on other published works. A mesh of the geometry was created and bone remodeling partial differential equations were incorporated. The mastication force was assumed constant and the damping factor was considered zero in our study. Finally, the calculated resonance frequencies of the implant-mandible portion assembly were utilized to obtain and assess the implant stability quotient. RESULTS: The results showed that a 6 % increase in the dosage rates of TGF-beta had the highest increase in ISQ values to 24.28 % from the baseline and the implant elastic modulus of 12.5 GPa caused a 21.55 % relative growth in the ISQ value of the baseline. The accuracy of the results was tested by the mesh convergence and sensitivity studies. CONCLUSIONS: Based on the results, TGF-beta had the most significant effect on the growth of ISQ, and the implant elastic modulus remarkably increased ISQ values when its value was close to the average values of the mandible equivalent elastic modulus.