Properties of injection-molded thermoplastic polyester denture base resins

Area of Science:

• Materials Science
• Biomaterials Engineering
• Dental Prosthetics

Background:

• Thermoplastic polyester resins offer potential advantages for denture bases.
• Injection molding is a viable fabrication technique for denture bases.
• Understanding material properties is crucial for clinical performance.

Purpose of the Study:

• To compare the mechanical and bonding properties of two injection-molded thermoplastic polyester denture base resins.
• To evaluate flexural properties, impact strength, and shear bond strength.
• To determine the suitability of these materials for denture applications.

Main Methods:

• Two types of injection-molded thermoplastic polyester denture base resins were used: polyethylene terephthalate copolymer and polycycloalkylene terephthalate copolymer.
• Specimens were prepared for flexural testing, Charpy impact testing, and shear bond testing (n=10).
• Key mechanical properties including flexural strength at proportional limit, elastic modulus, impact strength, and shear bond strength were measured.

Main Results:

• Polycycloalkylene terephthalate copolymer exhibited significantly lower flexural strength at the proportional limit and elastic modulus compared to polyethylene terephthalate copolymer.
• Polycycloalkylene terephthalate copolymer demonstrated significantly higher Charpy impact strength than polyethylene terephthalate copolymer.
• Shear bond strength was significantly lower for the polycycloalkylene terephthalate copolymer compared to the polyethylene terephthalate copolymer.

Conclusions:

• The tested injection-molded thermoplastic polyester denture base resins possess distinct material properties.
• Polycycloalkylene terephthalate copolymer shows a different mechanical profile, with reduced stiffness and strength but increased toughness.
• These property differences necessitate careful consideration for clinical selection and application in removable prosthodontics.