## 4 Discussion
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Clenching Tasks** & **Dental Implant System Parts** & **Central Incisor** & **Lateral Incisor** & **Canine** & **First Premier** & **Second Premolar** & **First Modular** & **Second molar** \\ \hline
**INC** & Dental implant & 19.278 MPa & 33.038 MPa & & & & & \\  & Abutment & 21.772 MPa & 46.608 MPa & - & - & - & - & - \\  & Abutment screw & 15.538 MPa & 21.346 MPa & & & & & \\ \hline
**ICP** & Dental implant & & & 24.704 MPa & 25.698 MPa & 39.887 MPa & 67.858 MPa & 83.292 MPa \\  & Abutment & - & - & 19.601 MPa & 22.875 MPa & 33.922 MPa & 46.864 MPa & 86.246 MPa \\  & Abutment screw & & & 12.443 MPa & 11.547 MPa & 22.712 MPa & 27.760 MPa & 54.327 MPa \\ \hline
**RMOL** & Dental implant & & & & & & & \\  & Abutment & - & - & - & - & - & 113.72 MPa & 113.99 MPa \\  & Abutment screw & & & & & & & \\ \hline
**RGF** & Dental implant & & & & & & & \\  & Abutment & - & - & - & - & - & 101.89 MPa & 87.328 MPa \\  & Abutment screw & & & & & & & \\  & Abutment & - & - & - & - & - & 58.614 MPa & 42.373 MPa \\ \hline
**RGF** & Dental implant & & & & & & & \\  & Abutment & - & - & - & - & - & 20.018 MPa & 59.300 MPa \\  & Abutment & - & - & - & - & - & 20.018 MPa & 47.492 MPa \\  & Abutment & - & - & - & - & - & 20.018 MPa &  
to the loading, which may cause deformations and tensions in cartilaginous structures [33]. RMOL mainly simulates the contact of the posterior teeth on the right side (unilateral). As an unbalanced occlusion, besides the fact that the occlusal force is concentrated on the posterior teeth, the external force applied by the muscles is also high. Thus, the reaction forces on the first molar (261.09 N) and second molar (214.91 N) are high, especially the reaction force on the first molar near the mesial side. Therefore, to avoid postoperative failure in patients, implantations in the posterior teeth region can use thicker implants capable of bearing greater external forces. Furthermore, in INC and RGF occlusions, the reaction forces on the fixed top ends of the abutment are relatively low (However, in the case of INC occlusion, the reaction force value of the fixed top of the abutment on the lateral incisor reaches 70.431 N. This value is greater than in some cases under the occlusion of ICP). INC mainly simulates the contact between incision edges. Since the muscles that produce this movement do not exert a strong force, only a small reaction force is generated on the central incisor. RGF mainly simulates the lateral movement of the right posterior teeth. Thus, the vertical force exerted by the muscles to the mandible is not strong, thus the reaction forces exerted on the canine, first premolar, second premolar, first molar, and second molar are also weak. In addition, according to the results of this study, the reaction force on the posterior region (26.968 N to 261.09 N) during occlusion is not necessarily greater than that on the anterior region (28.819 N to 70.431 N). The magnitude of the force on the dental implant is mainly determined by the external force given by the muscle on the mandible in different occlusion situations. The results of the FEA showed the external forces (magnitude and direction) applied to the dental implants at different positions under the four occlusal conditions. Thus, when conducting in vitro experiments or FEA of the biomechanics of dental implants in the future, the results of this study (the reaction force on the fixed top end of the abutment of each dental implant system) can be used as a reference for the setting of the loading conditions. Whereby different implant designs at different positions can be evaluated and that studies on the biomechanics of dental implants will not be limited by the application of a single vertical, horizontal, or oblique external force. The distribution of the von Mises stress in the entire mandibular bone shows that high stress occurs at the neck near the TMJ. This is because the cross-sectional area here is small, and thus when a force is passed, higher stress will be generated.