# In vitro comparative evaluation of the flexural strength of acrylic denture bases reinforced with nano-PEEK and PEEK–zirconia composites

## TL;DR

This study compares how adding nano-PEEK and zirconia to acrylic denture material affects its strength, finding that a hybrid mix improves durability.

## Contribution

The novel contribution is demonstrating that a hybrid of PEEK and zirconia nanoparticles significantly enhances PMMA's mechanical properties.

## Key findings

- The ZP group showed the highest flexural strength (139.78 MPa), significantly better than the control and PEEK-only groups.
- Hybrid PEEK-zirconia nanoparticles improved mechanical and structural behavior of PMMA.
- PEEK-only and control groups showed no significant difference in flexural strength.

## Abstract

Poly(methyl methacrylate) (PMMA) is the most widely used denture base material but exhibits limited fracture resistance under functional loads. This study investigates the effect of incorporating zirconia (ZrO2) and polyether ether ketone (PEEK) nanoparticles on the structural and mechanical properties of PMMA. Thirty rectangular heat-cured PMMA specimens (65 × 10 × 2.5 mm) were divided into three groups: Group C (control): unmodified PMMA; Group P: PMMA with 5% PEEK nanoparticles; and Group ZP: PMMA with a hybrid of 2.5% ZrO2 and 2.5% PEEK nanoparticles. Nanoparticle morphology was analyzed by field emission scanning electron microscopy (FESEM), showing PEEK sizes between 26 and 100 nm and spherical ZrO2 with a mean diameter of 47 nm. Energy-dispersive X-ray spectrometry (EDXS) was performed on ZrO2 only. FTIR analysis confirmed interfacial bonding in the hybrid composite. Flexural strength was measured via a three-point bending test. The ZP group exhibited the highest flexural strength (mean: 139.78 MPa), significantly outperforming both P and C groups (p < 0.05), with no significant difference between P and C. The synergistic addition of ZrO2 and PEEK nanoparticles significantly improved the mechanical and structural behavior of PMMA, offering a promising strategy to enhance durability and clinical performance of denture base materials in prosthodontics.

The online version contains supplementary material available at 10.1038/s41598-026-36102-3.