EVALUATION OF SOME MECHANICAL PROPERTIES OF POLY ETHER-ETHER-KETONE AS ALTERNATIVE TO POLYMETHYL-METH-ACRYLATE DENTURE BASE MATERIAL (AN IN VITRO STUDY)

Objectives: This in-vitro study was conducted to evaluate and compare the flexural strength and water sorption of a high-performance thermoplastic polymer, Polyetheretherketone (PEEK), against conventional heat-cured polymethylmethacrylate (PMMA) denture base material. Methods: Forty specimens were divided into PEEK (Group K, n=20) and PMMA (Group C, n=20) groups, then subdivided (n=10) for testing. For the flexural strength test, rectangular specimens (65×10×2.5 mm) were evaluated via a three-point bending test on an Instron 3345 machine in accordance with ISO 20795-1 at a crosshead speed of 5 mm/min. For the water sorption test, disc specimens (10 mm diameter × 2 mm thickness) were desiccator-dried to a constant weight, then immersed in distilled water at 37°C for one week. Weight changes were recorded using a highly precise four-digit analytical balance in accordance with ISO 20795-1 specifications. Statistical analysis was performed using Student’s t-test with the significance level set at (p < 0.05). Results: Statistical analysis revealed that the PEEK group recorded a significantly higher mean flexural strength (196.1 ± 7.6 MPa) compared to the PMMA group (125.6 ± 6.4 MPa) (p < 0.0001). Conversely, the PMMA group demonstrated a significantly higher mean water sorption percentage (0.65 ± 0.24%) than the PEEK group (0.30 ± 0.11%) (p < 0.0001). Conclusions: CAD/CAM-milled PEEK demonstrated superior flexural strength and significantly lower water sorption compared to PMMA. Consequently, it offers a highly durable, dimensionally stable alternative to overcome conventional acrylic resin limitations. Clinical relevance: Using CAD/CAM PEEK denture bases directly minimizes common clinical failures, such as midline fractures and partial denture clasp breakage. Furthermore, its minimal fluid absorption ensures long-term dimensional stability, color preservation, and excellent fit inside the oral cavity. Additionally, its biocompatible, monomer-free nature completely eliminates the risk of patient allergic reactions and mucosal irritation.