The Structural Integrity and Fracture Behaviour of Teeth Restored with PEEK and Lithium-Disilicate Glass Ceramic Crowns

Abstract

Polyetheretherketone (PEEK) is a unique polymer material which has recently been introduced to dentistry. This study aimed to assess the structural integrity of PEEK as a posterior tooth crown and compared it with ceramic-based material. A total of 31 monolithic CAD-CAM PEEK (JuvoraTM, Strumann, Andover, MA, USA) crowns and 31 lithium disilicate (IPS e.max®CAD, Voclar Vivadent AG, Liechtenstein) crowns were created and cemented on dentin-like teeth (AlphaDie®MF, Schütz Dental GmbH, Rosbach, Germany) in a precise procedure mimicking the physical and mechanical properties of natural teeth and periodontal ligaments. A static compressive strength test using a universal testing machine and a dynamic fatigue test using a chewing simulator machine were used until crown failure to assess the fracture behaviour by mode of fracture (fractographic analysis) and 3D digital subtraction analysis. The results showed that PEEK has a greater fracture resistance than IPS e.max®CAD by 2060 N to 703 N. Additionally, in fatigue limit, IPS e.max®CAD showed a constant failure under 2.0 Kg (=320 N) before 5000 chewing cycles while PEEK survived at a significantly higher load > 11 Kg (930 N). Furthermore, PEEK showed a continued survival at >1,250,000 cycles while the mean fatigue life of IPS e.max®CAD was around 133,470 cycles. PEEK illustrated a significantly less catastrophic failure mode with some plastic deformation at the fractographic stereomicroscope and in the 3D digital subtraction analysis. Using PEEK for crowns looks very promising, however, further clinical studies are required to assure this study’s results.

Qualitative SEM analysis of fracture surfaces for dental ceramics and polymers broken by flexural strength testing and crown compression

“…The fabrication of dental restorations has been simulated in research laboratories for in vitro studies with standardized specimens (bars and discs) to study the quality of the material as provided by the manufacturer; to expose the specimens to conditions similar to the oral environment (low‐temperature degradation 7 ) and dental laboratory (finishing, polishing, and sandblasting); and to determine the mechanical properties (failure load, 8 flexural strengths, 9–12 fracture toughness, 13 wear, 14 and fatigue) 15 …”

Barrier Membrane in Regenerative Therapy: A Narrative Review

“…It is widely used in the medical field as an excellent alternative to titanium in orthopedics [ 77 ]. The research and application of PEEK in dentistry are extensive; specifically, it has been used as a dental implant, provisional abutment, obturator, denture base, clasp for dentures and others because of its good biological, mechanical, aesthetic and handling properties [ 78 , 79 , 80 , 81 , 82 , 83 ]. Given its excellent mechanical properties and structural integrity, PEEK has been suggested by Papia et al to be used as a barrier membrane in complex three-dimensional surgery, because of its satisfactory mechanical properties under tensile and flexural strength with the thickness range of 0.5–1.0 mm, making it a desirable material for regeneration therapy [ 84 ].…”

Fracture Resistance of Provisional Crowns Fabricated by Conventional, CAD/CAM, and 3D Printing Techniques

“…This premolar was prepared to receive an all ceramic crown. The preparation was carried out by using CNC (centroid milling machine) with 2mm occlusal reduction, 1.5mm axial reduction, 1mm deep chamfer finish line circumferentially at 1mm above the cementoenamel junction, and a convergence angle of 6 degree (13) .…”