# Proposal for a New Bioactive Kinetic Screw in an Implant, Using a Numerical Model
## 2 Materials and Methods  
To describe this ongoing research, an explicit dynamic numerical model was developed using ANSYS 2020 R2 (r)--Workbench 2020 R2 with the new BKS biomechanical [19] in titanium alloy versus cortical bone material. This program is a nonlinear transient dynamic finite element program with an explicit time scheme function. The equation of motion is evaluated in the previous time step and works in time step increments, where displacements are calculated as time progresses. Gradually, over time, the deformation also changes. The numerical model aims to simulate the drilling process of the BKS biomechanical and evaluate the mechanical stress distribution in the bone material. The new BKS biomechanical, as seen in Table 1, also presents itself as a new delivery system for the use of natural growth factors (GF), since the characteristic of the new biomechanical is to introduce protein molecules, cells, blood, and particulate bone through the new screw hole by a drill channel system as an innovative biomechanical; it also becomes a new means of delivery of GFs in surgery for bone expansion, lifting, and fixation [1]. Adding the advantages of using homogeneous autogenous bone (new gold standard to be tested), its macro design is bioactive for the first time in bone implants. To observe chip formation and chip flow mechanism in a virtual environment, an explicit dynamic finite element analysis must be done with the BKS tool and bone work piece interaction. The BKS diameter is 4 mm and the bone workpiece material has a diameter of 10 mm in diameter, a height of 8 mm, and a central hole of 2 mm with a height of 2 mm. In this work, three-dimensional finite element modelling, and numerical analysis were carried out to simulate the dynamic process of dental bone perforation. The 3D models were built in Solidworks (r)and ANSYS 2020 R2 (r)--Workbench 2020 R2 software programs. The BKS modelling was carried out in Solidworks and imported into ANSYS Workbench, as shown in Figure 1. After importing the Solidworks model into ANSYS, a bone block (workpiece) was constructed, representing the surrounding dental bone. Several authors used the Johnson-Cook model, or its modified formulations [20; 21; 22; 23; 24; 25], to investigate and describe problems in which the strain-rate component was relevant. The Johnson-Cook model is the simplest model able to predict the mechanical behaviour of the materials under different loading conditions. It is one of the most used material models, so it is implemented in many finite element codes, and therefore the values of the Johnson-Cook parameters for different materials are quite easy to find in the literature. In the study, both models were modelled by Johnson-Cook material for explicit behaviour, where titanium alloy was chosen as the screw and the workpiece was in bone material. The mechanical properties of the materials used in the study are shown in Table 1.  
Titanium alloys are the most attractive metallic materials for biomedical applications, and are used for various implants and dental devices [26]. Ti6 Al4V is heterogeneous and used for different medical implants, namely for dental osseo-integrated screws [26]. The chemical composition of Ti6 Al4V is almost 90% titanium, 6.19% aluminium, 3.67% vanadium, 0.17% iron, and 0.12% oxygen [26]. Based on the geometrical models, finite element meshes were generated. The numerical model was prepared in ANSYS 2020 R2 (r)--Workbench 2020 R2. The BKS model and the bone disc were meshed with 3D SOLID elements. Lagrangian finite element model-based simulations were performed to determine the effective stress and the effective strain. Different mesh convergence tests were performed to minimize computational error. Figure 2 represents the mesh model and all applied boundary conditions.