Polyetheretherketone (PEEK) is a semi-crystalline linear polycyclic thermoplastic that has been proposed as a substitute for metals in biomaterials. PEEK can also be applied to dental implant materials as a superstructure, implant abutment, or implant body. This article summarizes the current research on PEEK applications in dental implants, especially for the improvement of PEEK surface and body modifications. Although various benchmark reports on the reinforcement and surface modifications of PEEK are available, few clinical trials using PEEK for dental implant bodies have been published. Controlled clinical trials, especially for the use of PEEK in implant abutment and implant bodies, are necessary.

Clasp retainers made of metal alloys may be esthetically unappealing or cause allergic reactions. To investigate alternative materials, we used the nonfiller polyetheretherketone (PEEK) to fabricate the clasp retainer of a removable partial denture for the mandibular bilateral distal free-end abutment of an 84-year-old female. Two years later, few color and texture changes of PEEK were found macroscopically. The rest part and the clasp arm fitted well without any deformation. There were no particular occlusal or periodontal problems. Subjective satisfaction was expressed by both the practitioner and the patient.

To introduce a new clinical procedure for fabricating duplicates of complete dentures by bite pressure impression using digital technology, and to discuss its clinical significance. The denture is placed on a rotary table and the 3-dimensional form of the denture is digitized using a general-purpose handheld optical scanner. The duplicate denture is made of polylactic acid by a 3-dimensional printer using the 3-dimensional data. This procedure has the advantages of wasting less material, employing less human power, decreasing treatment time at the chair side, lowering the rates of contamination, and being readily fabricated at the time of the treatment visit.

These days, new prosthodontic materials are appearing with the development of digitalization. Among these, the use of polyetheretherketone (PEEK) as the clasp of removable partial dentures has been proposed. The adhesive strength between the PEEK and acrylic resin influences the probability of denture fracture. To investigate the effect of PEEK surface treatments on the shear bond strength to acrylic resin, five surface treatment conditions of PEEK were analyzed: 1. no treatment; 2. ceramic primer application; 3. Al₂O₃ sandblasting; 4. Rocatec; and 5. Rocatec with ceramic primer application, comparing with a metal primer-treated Co-Cr alloy. Two kinds of autopolymerizing resin (Unifast II and Palapress Vario) were used as bonding materials. The specimens were evaluated to determine the bond strength. Rocatec treatment with ceramic primer application yielded the highest bond strengths (12.71 MPa and 15.32 MPa, respectively, for Unifast II and Palapress Vario). When compared to a metal primer-treated Co-Cr alloy, the bond strength of PEEK to Unifast II was similar, whereas it was about 60% of that to Palapress Vario. Rocatec treatment, combined with ceramic primer, showed the highest bond strength of PEEK to acrylic resin. Treatment of PEEK will enable its use as the clasp of removable dentures and the fixation of PEEK prostheses.

The mechanical properties of seven denture adhesives and eight oral moisturizers, all of which are commercially available, were evaluated using a texture profile analysis. A new assessment chart is proposed for the selection criteria of denture adhesive and oral moisturizers using a radar chart with three axes: hardness, cohesiveness, and adhesiveness.

A previously developed carbon fibre-reinforced addition-type polyimide composite material was exposed to temperatures of 240, 270 and 300 °C in air for 3000 h to study its long-term stability in terms of its compressive strength. The in-plane shear modulus, compressive failure mode and transverse crack density were also evaluated to determine whether a degradation process induces a decrease in the compressive strength of a high-temperature polymer matrix composite having a laminated configuration of [90/0]_4s. The carbon fibre-reinforced polyimide composite exhibited excellent thermal stability in terms of its compressive strength after being subjected to ageing at 240 °C for 3000 h and at 270 °C for 2000 h, with degradation becoming significant at 300 °C. The compressive strength decreased only when the surface degradation caused the 90° plies sandwiching the 0° plies to degrade severely.