D8 discover

The macroscopic fracture appearance of the fractured PEEK crowns was observed visually. To observe the microscopic fracture pattern of PEEK crowns, the non-conductive fracture surface was analyzed using a scanning electron microscope (SEM) (JSM-6500F, JEOL, Tokyo, Japan) with secondary electron image mode and 15 kV acceleration voltage after being coated with a thin (~10 nm) conductive platinum film. Meanwhile, an energy dispersive spectrometer (EDS) (Ultim Max 100, Oxford Instruments, Abingdon-on-Thames, UK) with mapping analysis mode was used to analyze the elemental distribution of titanium (Ti), oxygen (O), and carbon (C) on the fracture surface to confirm the dispersion of TiO₂ particles in the PEEK matrix. Furthermore, the crystallinity of the fracture surface was analyzed using a high-intensity X-ray micro-area diffractometer (D8 Discover, Brucker, Billerica, MA, USA) with beam sizes down to 180 × 180 μm² to investigate the crystalline structure of test PEEK crowns. The measured 2θ ranged from 10 to 80°, with a scanning rate of approximately 1° per minute.

For determining the extent of crystallinity of the EFs, X-ray diffraction was performed using a D-8 Discover diffractometer (Brucker) at 2θ position ranging from 5–50° and 40 kV.

The crystal structure was investigated using a Brucker D8 Discover diffractometer with Cu K alpha radiation of 0.154 nm operating at 40 kV and 40 mA in parallel beam configuration. Grazing incidence at an angle of 0.5° was used as investigation method.