Mechanical properties of 3D printed denture base polymers

Area of Science:

• Biomaterials Science
• Dental Materials Science
• Additive Manufacturing

Background:

• Limited data exists on the mechanical properties of 3D printed denture base polymers using standardized testing methods.
• Evaluating these properties is crucial for clinical application and material development.

Purpose of the Study:

• To determine flexural strength (σf), elastic modulus (E), fracture toughness (KIC), work of fracture (ωe), and Martens hardness (HM) of 3D printed denture base polymers.
• To compare these mechanical properties against an injection-molded control material.

Main Methods:

• Three additive manufacturing resins (Lucitone Digital Print, Flexcera Base, experimental) and one injection molding resin (IvoBase Hybrid) were analyzed.
• Specimens underwent fabrication, polishing, tempering, and thermal cycling before mechanical property testing.
• Statistical analysis included Kolmogorov-Smirnov tests and parametric/nonparametric pairwise comparisons (α=.05).

Main Results:

• 3D printed polymers showed significantly lower flexural strength (σf), elastic modulus (E), and Martens hardness (HM) compared to the injection-molded material, both before and after aging.
• Fracture toughness (KIC) and work of fracture (ωe) were highest for a specific 3D printed polymer (LDP) after aging, while others were comparable.
• The injection-molded material (IBH) was unaffected by artificial aging, unlike the 3D printed resins.

Conclusions:

• Printable denture base polymers generally exhibit inferior σf, E, and HM compared to conventional injection-molded materials.
• Certain 3D printed materials demonstrate competitive or superior KIC and ωe, suggesting potential for improved fracture resistance.
• Tension testing is recommended for evaluating ductile materials like these, alongside traditional bend tests.