Performance of Graphene-Based and Polyether-Ether-Ketone Polymers as Removable Partial Denture Esthetic Clasp Materials after Cyclic Fatigue

Abstract

The esthetic clasp material is a clinical demand for a satisfactory removable partial denture. The purpose of this study is to assess the mechanical performance of graphene-based polymer (GBP) and polyether-ether-ketone (PEEK) materials as clasp materials. Thirty-two clasps were fabricated by CAD-CAM from two materials, GBP and PEEK. All clasps were tested for retention force after 10,000 cycles of insertion and removal and thermocycling. The clasp arms’ deformation was measured, and areas of stress–strain concentration were explored. The Mann–Whitney U test was used to compare the retentive force of the studied groups, while the independent sample t-test was applied to check the difference in clasp arm deformation at α = 0.5. The results showed a significantly higher retentive force (2.248 ± 0.315 N) in PEEK clasps, at p < 0.001. The deformation of the clasp arm of the GBP clasps was significantly higher than PEEK clasps. Areas of stress–strain concentration were seen at the junction of the retentive arm to the minor connector and at the retentive arm terminal. It could be concluded that PEEK polymer had a better mechanical performance as an esthetic clasp material than the GBP. An optimization study for GBP might be required to check the validity of such an application.

Dimensional Optimization of Graphene-Modified Polymethyl Methacrylate Material Used as an Aesthetic Removable Partial Denture Clasp Material

“…It is a PMMA polymer enhanced by graphene nanomaterial with an elastic modulus (3.2 GPa). 17,24 This value is close to polymers used for a such application as PEEK (3.0-5.5 GPa) and far beyond alloys such as Cr-Co (200 GPa), which allows reduced clasp thickness and width. 1,26,[31][32][33] However, the material has the required flexibility to act as clasp material but is not rigid enough to be shaped in small and thin sections.…”

“…38,39 Previous studies showed higher stress values at the connection between the retentive clasp arm and the guiding plane, rendering it more prone to fracture. 1,24,26,38 Thus, keeping larger dimensions in that area is wise to endure stress concentrations. Although adequate tapering of the clasp tips is mandatory for metallic clasps because of their high rigidity, higher flexibility renders polymer clasps acceptable in less tapering values.…”

“…It also encouraged optimization studies for the material before clinical application. 24 To the best of the author's knowledge, no study has investigated optimizing the dimensions of a clasp made with CAD-CAM technology from graphene-doped PMMA. Thus, the current study aimed to assess the optimal dimensions of aesthetic clasps milled from graphene-doped PMMA CAD-CAM disks by a validated parametric FEA.…”

“…Bending and retention force laboratory simulations considering cyclic fatigue have been studied. 10 13 24 25 Virtual analysis by digital mathematical methods as the finite element analysis (FEA) was also considered. 1 26 Because of the marked difference in the elastic modulus of the tested polymers versus the frequently used alloys, less retention force was generated.…”

Clinical Applications of Polyetheretherketone in Removable Dental Prostheses: Accuracy, Characteristics, and Performance

“…It also allows for a comparison of any permanent distortion of the clasps following prolonged cyclic testing, which would be expected to have a detrimental effect on clasp retention [ 72 ]. Hussein [ 73 ] evaluated the retentive force after cyclic aging and the pull-off force of removable partial denture clasps manufactured from PEEK and GBP (graphene-based polymer) materials. The analog tooth material selected was CoCr material.…”