Fracture Load of Polyaryletherketone for 4-Unit Posterior Fixed Dental Prostheses: An In Vitro Study

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Mechanical Engineering

Background:

• Evaluating mechanical properties of CAD-CAM materials for fixed dental prostheses (FDPs) is vital for posterior load-bearing applications.
• Understanding fracture load and patterns informs material selection for long-term prosthesis success.

Purpose of the Study:

• To assess and compare the fracture load, modulus of elasticity, and fracture patterns of four-unit posterior FDPs fabricated from PEEK, PEKK, 3Y zirconia, and 4Y zirconia.
• To determine the suitability of these CAD-CAM materials for high-stress dental restorations.

Main Methods:

• Sixty-eight four-unit FDP frameworks were fabricated from PEEK, PEKK, 3Y zirconia, and 4Y zirconia.
• Three-point bending tests were conducted to evaluate fracture load and modulus of elasticity.
• Fracture patterns were analyzed visually and via scanning electron microscopy (SEM).

Main Results:

• 3Y zirconia exhibited the highest fracture load (2275 N), followed by 4Y zirconia (1034 N), PEEK (883 N), and PEKK (402 N).
• PEEK demonstrated ductile fracture, while PEKK and both zirconia groups showed brittle fracture patterns.
• PEEK and 4Y zirconia had similar fracture loads but distinct failure behaviors.

Conclusions:

• Material selection for posterior FDPs requires consideration of both fracture load and failure mode.
• 3Y zirconia offers superior fracture resistance but lacks flexibility; PEKK shows the lowest mechanical performance.
• PEEK and 4Y zirconia present viable options with different mechanical profiles for posterior restorations.