PEEK polymer, consisting of polyphenylene oxide, has excellent stability at temperatures above 3000℃, and is more tolerant than many metals. It is hydrophobic and insoluble in any solvents except high-concentration sulfuric acid. Its resistance to hydrolysis makes it a better material than carbon fiber. The material also has high radiation stability and is X-ray penetrable. Compared with other currently used materials such as titanium and zirconia, it is a lightweight material with strong resistance to deformation and excellent biomechanical performance. It has a very good polishing effect, so there is little tendency for residual plaque.
The color of polyetheretherketone is white, so it has good aesthetics and customization possibilities. It is biocompatible because it is insoluble in water and is an ideal choice for allergy sufferers. It is also a material that does not corrode, so it will not degrade due to saliva, acidic pH, food or drink, plaque, etc. It will not degrade due to aging and is very resistant to gamma and X-rays, feeling like a chemically stable material.
PEEK can be combined with other materials such as carbon fiber or ceramic particles (BioHPP) to improve some of its properties. In terms of elastic modulus, polyetheretherketone reinforced with carbon fiber can even be comparable to cortical bone and dentin, reducing potential pressure on bones, avoiding resorption, and future damage.
PEEK can exist in the form of granules, powder, or ultra-fine powder, depending on the molding technology used.
Injection molding: It involves injecting molten polymer through a small hole called a sprue into a closed, cold molding tool that fills all spaces and takes on the shape of the desired part; granules are recommended.
Extrusion molding: It uses a screw conveyor; the polymer is transported from the hopper, through the heating chamber, and to the outlet; loose powder is recommended.
Compression molding: This is a process of molding parts where the polymer is introduced into an open mold and then subjected to pressure and heat to take the shape of the mold; ultra-fine powders are recommended.
Two manufacturing processes, injection process and CAD-CAM process, are described for the use of PEEK polymer in dental restorations. In the latter, a milling machine is used to manufacture the previously designed structure from some PEEK blocks.