Polyetherketoneketone (PEKK): An emerging biomaterial for oral implants and dental prostheses

Abstract

Polyetherketoneketone (PEKK) is a new evolving polymeric material. The present article comprehensively reviewed an overview of various applications of PEKK in prosthodontics and oral implantology, highlighting its prospects for clinical applications. PEKK biomaterials is an elastic material with good shock absorbance and fracture resistance and present ultra-high performance among all thermoplastic composites for excellent mechanical strength, chemical resistance, and high thermal stability. Available articles on PEKK for dental applications were reviewed from January 1957 to August 2020) using MEDLINE/PubMed, Web of Science, and ScienceDirect resources. PEKK presents suitable physical, mechanical, and chemical properties for applications in prosthodontics and oral implantology. PEKK has good potential for a wide range of dental applications, including tooth restorations, crowns, bridge, endoposts, denture framework, implant-supported fixed prosthesis, and dental implants. PEKK dental implants have shown lesser stress shielding compared to titanium for dental implant applications. Further modifications and improving material properties can result in broader applications in the field of dentistry. Long term evaluations are needed as PEKK is recently applied in dentistry, and there are limited studies published on PEKK.

Keywords: Dental implants; High-performance polymer; PEKK; Prosthodontics; Restorations, dental.

Graphical abstract

Fig. 1

Structure and performance of PAEK (PEKK and PEEK), and fabrication of PEKK. (A) Performance of PAEK; (B) Structures of PAEK; (C) Production of PEKK by electrophilic substitution using nitrobenzene and aluminum chloride (AlCl₃). PAEK = Polyaryletherketone, PEEK = Polyetheretherketone, PEKK = Polyetheretherketone, PPS = Polyphenylene sulfide, PAI = Polyamideimide, PES = Polyethersulfone, PEI = Polyethylenimine, POM = Polyoxymethylene, PC = Polycarbonates, PA = polyamide, PMMA = Polymethyl methacrylate.

Fig. 2

Current and potential applications of PEKK in dentistry.

Fig. 3

(A–C) Various PEKK implant prostheses made by Pekkton (Cendres + Métaux, Switzerland) containing monolithic and bi-layered veneered resin; (D–K) Use of PEKK for implant prosthesis framework with single lithium disilicate glass-ceramic crowns . (D) Diagnostic tooth arrangement following the duplication of maxillary and mandibular interim dentures. (E) Maxillary framework resin pattern. (F) Maxillary teeth fitted on resin pattern framework. (G) Maxillary resin pattern framework for investment. (H) Teeth fitted over PEKK frameworks on maxillary and mandibular casts. (I) Maxillary complete denture, and mandibular implant-supported prosthesis. (J) Tissue surface of the maxillary denture. (K) Frontal view of the completed maxillary complete denture and mandibular implant-supported prosthesis.

Fig. 4

PEKK framework material for rehabilitation of a mandibulectomy patient . (A) Panoramic radiograph of mandible following reconstruction with fibula free flap. (B) Trial denture. (C) PEKK framework fabricated after scanning the completed wax trial denture. (D) Final prosthesis after adding gingiva opaquer and gingiva-colored resins to match the gingiva, and cementing PMMA crowns to the framework. (E) Intraoral view of the prosthesis. (F) Final prosthesis in the patient. (G) Panoramic radiograph at follow up visit.

Fig. 5

Digital workflow for the fabrication of a PEKK in removal speech bulb prosthesis . (A) Pretreatment maxillary arch with a defect of the soft palate. (B) Intraoral scan of the maxillary arch. (C) Computer-aided design of PEKK framework with showing components design of PEKK framework. (D) Computed-aided manufacturing showing milled framework in PEKK disk. (E) PEKK framework on the master cast. (F) Maxillary edentulous area definitive impression, maxillo-mandibular record, and impression of the soft-palate defect. (G), Final PEKK removable prosthesis. (H) Maxillary major connector. (I) PEEK rod and acrylic bulb of the prosthesis. (J) Intraoral view of the removable prosthesis with speech bulb.

Fig. 6

Stress distribution of the PEEK post compared to gold post-core and fiberglass post with resin core . (A) Sagittal section views of stress distribution of the components. (B) Coronal section views of the stress distribution at the labial side interface surface of dentine and post cement along the mid-plane.