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ORIGINAL RESEARCH
Year : 2023 | Volume
: 14
| Issue : 2 | Page : 45-48
Bilinear Numerical Analysis of the Structural Behavior of a Dental Implant Applied as a Biomaterial Carbon Fiber Reinforced Polyether-Ether-Ketone (CFR-PEEK): A Finite Element Analysis
Miguel Martinez-Mondragon, Guillermo Urriolagoitia-Sosa, Beatriz Romero-Ángeles, Juan C Pérez-Partida, Itzel M Cruz-Olivares, Guillermo Urriolagoitia-Calderón
Instituto Politécnico Nacional, Escuela Superior de Ingeniería Mecánica y Eléctrica, Sección de Estudios de Posgrado e Investigación, Unidad Profesional Adolfo López Mateos “Zacatenco”, Ciudad de México, México
Correspondence Address:
Guillermo Urriolagoitia-Sosa
Instituto Politécnico Nacional, Escuela Superior de Ingeniería Mecánica y Eléctrica, Sección de Estudios de Posgrado e Investigación, Unidad Profesional Adolfo López Mateos “Zacatenco”, Ciudad de México
México
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/denthyp.denthyp_42_23
Introduction: This research aims to compare the distribution of stresses and general displacements between different dental implant abutments against a healthy tooth, as well as the mechanical behavior of the carbon fiber-reinforced polyether-ether-ketone (CFR-PEEK) material under load conditions. Methods: A biomodel of a healthy tooth was implemented by computed tomography (CT), considering three essential parts of the tooth (enamel, dentin, and pulp). Three different dental abutments were produced using the SolidWorks computer program. Applying the finite element method (FEM), a numerical evaluation was performed by introducing a critical load of 550 N and then unloading it to 0 N taking into consideration the behavior of the material (titanium and CFR-PEEK) as bilinear, isotropic, and homogeneous. Results: The difference in stress and total displacement between the dental implant (titanium and CFR-PEEK) and the healthy tooth was significant, going from critical stress values of 1087 to 324 MPa. Conclusion: When removing the load from the CFR-PEEK material, it presented residual stresses because the material passed its elastic limit despite this, demonstrating a better mechanical behavior than titanium.
Keywords: Bilinear behavior, dental implant, finite element analysis, numerical analysis, PEEK
In the last four decades, pure titanium and titanium alloys have been used as a biomaterial for the manufacture of dental implants, with an effectiveness rate of 90% due to their high mechanical resistance.[1],[2] However, polymeric materials that have proven to be suitable for biomedical applications have entered the competition, they also have excellent physical and mechanical properties, as well as good biocompatibility.[3],[4] One of the materials that has attracted attention is polyether-ether-ketone (PEEK), which belongs to the family of poly aryl ether-ketones (PAEK).[5] Polyether-ether-ketone (PEEK) is a polymeric material that emerged in the late 1970s.[6] It is a polymer with a semi-crystalline structure with excellent biological, mechanical, and physical properties, such as wear resistance, thermal and chemical stability, good biocompatibility, and a modulus of elasticity more similar to human cortical bone (3-4 GPa).[7],[8],[9] The recent research aims to perform a numerical analysis for three types of dental implant abutments with two different materials (titanium and polyetheretherketone) comparing their mechanical behavior and effects with the biomodel of a healthy tooth.
Materials and MethodsFor this research work, were carried out seven numerical simulations and distributed in three case studies. The dental implant models were developed for a lower right first molar with a diameter of 5.5 mm and a length of 14 mm. The type of connection is internal hexagonal conical. The parts model for the implant consisted of three; the body of the implant, the abutment, and the prosthetic screw [Supplementary Figure 1].[10] The manner in which to apply the load was based on the ISO 14801 standard for fatigue tests, which specifies that the dental implant must be placed at 30° concerning the direction of the loading system (vertical). It is worth mentioning that a fatigue analysis was not performed, the parameter was simply taken as a reference. The bite force of a human was obtained based on studies where the magnitude of the masticatory force is between 22 and 55 kg (200-550 N).[11],[12] The numerical simulations of the dental implants were carried out as a bilinear analysis to observe the plastic behavior (permanent deformation) and effects in each material when the load acts. All finite element simulations were carried out using the Ansys Student 2022 R2 software (ANSYS, Inc., San Diego, CA, USA).
First case of study
For the first case study, a three-dimensional biomodel of a first right lower molar of an apparently healthy 37-year-old patient was performed. It was developed using the 3D Slicer program (www.slicer.org) based on computed tomography. It consists of three main parts: enamel, dentin, and pulp [Supplementary Figure 2].[10],[13],[14] The mechanical properties of the tooth are shown in Supplementary Table 1.[10],[15],[16] The boundary conditions were applied in the area of the root of the tooth (dentin), restricting the movement of its six degrees of freedom (Ux, Uy, Uz, Rotx, Roty, and Rotz). The external conditions were placed on the occlusal face of the tooth applying a critical load of 550 N at 30°. The force vector was decomposed into two vectors (axial and tangential). [Supplementary Figure 3].[10]
Second case of study
For the second case study, three different dental implant abutments (snappy, universal, and esthetic) were modeled [Supplementary Figure 4][10] using the SolidWorks (CAD) program (Dassault Systèmes SolidWorks Corp., Waltham, MA, USA). These were selected from the models developed by the Swiss company Nobel Biocare (Kloten, Switzerland).
The boundary conditions and external agents were placed in the body part of the dental implant and the upper part of the abutment respectively [Supplementary Figure 5],[10] applying the same critical load of 550 N at 30° but now adding to the analysis the effect caused when the critical load is removed. The material used for this second case study was alpha-beta titanium alloy (Ti6Al4V).[17] The mechanical properties are described in Supplementary Table 2.[10]
Third case of study
For the third case of study, the same considerations were made as in the first two cases, except for the material, which in this case used polyether-ether-ketone with carbon fiber reinforced, which is considered biocompatible material. The analysis is carried out for the same three implants as in previous cases. The mechanical properties of CFR-PEEK are described in Supplementary Table 3.[10]
ResultsThe results obtained from the numerical simulation manifest the structural behavior that is shown graphically in terms of displacement and forces for each case study. In the case of the tooth and the behavior when applying the critical load [Supplementary Figures 6-7][10] and in the case of dental implants shows two structural behaviors: one when loading (left side) and the other when unloading (right side) [Supplementary Figures 8-18'].[10] All the results obtained in this research are shown in Supplementary Table 4.[10] Finally, of all the simulations that presented the best structural behavior was the Esthetic abutment [Figure 1].
DiscussionsRegarding the first case study, the results indicate that the maximum displacement is occurring in the lingual area and maximum effort is manifested mostly in the dental crown. The critical stresses were presented throughout the periphery of the crown due to the curvature, behaving as stress concentrators, with maximum values between 600 and 700 MPa. These results were comparable with reports by Hernández-Vázquez et al.,[15],[16] where displacements tend to be very similar in the areas of the tooth. However, our results differ in the values of effort due to the different morphology of the tooth.
In the second and third case studies the results of the bilinear analysis indicate that the three different dental abutments with titanium alloy have a linear-elastic structural and mechanical behavior as in the case of the tooth while with CFR-PEEK the structural and mechanical behavior is nonlinear (elastoplastic) as shown in [Figure 2].
Figure 2 Mechanical behavior between titanium alloy and carbon fiber reinforced polyether-ether-ketone.The permanent deformations that are located in a part of the CFR-PEEK abutment indicate that there are residual stresses that affect susceptibility to fractures and fatigue. That is why the authors consider that a fatigue analysis must be carried out in the future to find out if it is a risk to work with this material in the plastic area. These results were compared with a previous report by Martinez-Mondragon et al.,[17] where it is shown that when nonlinear conditions are applied, materials tend to behave more similarly to reality.
The limitations of our study were in the case of the tooth which it was difficult to apply a bilinear numerical analysis because the mechanical properties of the tooth when it exceeds the elastic limit are difficult to predict since each person is different. In the case of dental implants, the analysis was limited to considering the part of the bone and other aspects of the tooth such as the dental cementum and the periodontal ligament. Although it is intended to be done in the future.
So, the development presented in this research is based on knowing the effects produced by the critical load that occurs in the chewing process (maximum load when biting). The application of the finite element method for numerical simulations has the advantage of being able to solve complex model systems for the different study areas. This type of evaluation has managed to substantially reduce experimental evaluation processes in which standards and regulations are even involved, as in the case of experimentation with living beings (biological systems). Finally, the use of imaging studies for the development of numerical biomodels of biological systems allows the development of assessments closer to reality and the possibility of implementing innovative methodologies or procedures that optimize the way of estimating any pathology.
ConclusionsPolymeric dental implants are an alternative that does not include metal and are also useful in patients with allergies. Without leaving aside the versatility they have to be compatible with the human body.Carbon fiber-reinforced polyetheretherketone may be a potential material for implant applications due to its acceptable mechanical properties and low density.Although titanium is a material with high rigidity, carbon fiber-reinforced polyetheretherketone showed better stress behavior with lower critical stress values than titanium.Acknowledgments
The authors gratefully acknowledge the Instituto Politécnico Nacional and the Consejo Nacional de Ciencia y Tecnología for their support of this research.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
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