Three-Dimensional finite element analysis of tooth and implant-supported telescopic prosthesis using zirconia, PEKK, and cobalt chromium crowns

Objectives. Telescopic prosthesis is one of the treatment options to rehabilitate partially edentulous cases supported by the teeth and implants using different material. This study investigates the stresses pattern of telescopic, double-crown, prostheses connecting natural teeth and implants, utilizing various material combinations for the primary and secondary crowns. Materials and Methods. Three dimensional (3 D) Finite Element Analysis (FEA) was employed in this study to facilitate the visualization and measures of Von misses stress distribution across the prosthetic structure, identifying areas susceptible to stress concentration. A patient simulated digital mandibular model with two canines and two implants in the first molar area was constructed and nine groups of prostheses were created using Zirconia, PEKK, and Cobalt-Chromium. ANSYS 9.0 version software was used to create the model and the nine groups of the telescopic prosthesis, apply the load and get the stresses and deformation of the different material of telescopic prosthesis and the stresses on the supporting structures. The occlusal loads were exerted on the anterior, canines, about 100-N axial load, and also 250-N axial load was applied in the posterior region, bilaterally. Results. Von Mises stress analysis showed that the use of PEKK as a primary crown, in comparison to the zirconia and cobalt chromium, leads to decreased stresses on the primary and secondary crown whatever was of the material of the secondary crown used but it not affect the stresses transmitted to the supporting structures, either the bone, teeth, and implants. Conclusions. In comparison to the Zirconia, and Cobalt-chromium, PEKK decreased stresses on double crowns while transferring increased stresses to the supporting structures when utilized as a secondary crown. PEKK, on the other hand, decreased stress on the prosthetic components when used as a primary crown, but it had no effect on the stress levels in the supporting structures. Clinical Relevance. The selection of materials had a major impact on the distribution of stresses transmitted to the prosthesis and the supporting structures, teeth and implants. PEKK decreased stresses on prosthetic components but increased the stresses to the supporting structure. In every material combination, implants were subjected to more load than natural teeth.PEKK is not recommended as a secondary crown material if the goal of the treatment was to protect the weak supporting teeth and implant; zirconia or cobalt-chromium can be utilized instead.