Abstract
OBJECTIVE: The current study used finite element analysis (FEA) to investigate the rigidity, through Von-Mises stresses and deformation of cobalt-chromium, Polyetheretherketone (PEEK), Polyetherketoneketone (PEKK), and BioHPP constructed for mandibular class I RPD with lingual bar major connector. Although the general stress-strain relationships followed expected mechanical behavior, this study provides quantitative insight into how different polymeric materials (PEEK, PEKK, BioHPP) compare with conventional cobalt-chromium frameworks under identical loading conditions. MATERIALS AND METHODS: Four virtual models for mandibular Kennedy's class I situations, with the remaining eight anterior and premolar teeth, were generated that closely resemble the actual cases. Mandibular cobalt-chromium class I RPD with lingual bar major connectors, half pear-shaped, with standard dimensions (50 × 5 × 3 mm), was constructed as a control group. Another 3 models similar to the control group in dimension but with 3 materials, PEEK, PEKK, and Bio HPP, were constructed as study groups. 3D finite element analysis was done, and data were collected and analyzed using bar chart. RESULTS: The PEEK, PEKK, and Bio HPP major connectors showed more deformation (0.1798, 0.17554, 0.17104)mm, indicating weaker rigidity than the cobalt-chromium (0.028999)mm. The maximum von Mises stresses of the cobalt chromium lingual bar were 646.14 MPa, demonstrating stronger rigidity than the PEEK, PEKK, and Bio HPP, which exhibited values of 303.28, 295.29, and 301.23 MPa, respectively. In the case of PEEK and Bio HPP, greater stresses were transmitted to the supporting structures, particularly the mucosa, with maximum von Mises stress values of 3.0319 and 2.3047 MPa. These values were higher than the maximum stress transmitted to the mucosa in cobalt chromium, which was 0.60382 MPa. However, PEKK transmitted lower stresses to the supporting structures, particularly the mucosa, with a maximum von Mises stress value of 0.082096 MPa. CONCLUSION: Using the same size of PEEK, Bio HPP as the optimal dimensions of the cobalt chromium major connector of the mandibular class I RPD causes increased stress and deflection to the supporting structure, teeth, and soft tissues. This can be assigned to the PEEK's, Bio HPP, lower stiffness compared to cobalt chromium. On the other hand, PEKK showed decreased stresses and deflection of the supporting structure. When using PEEK and Bio HPP for class I RPD, the mandibular major connector must be larger.