Compressive creep of denture base polymers

Area of Science:

• Materials Science
• Biomaterials Engineering
• Dental Materials

Background:

• Denture base materials are crucial for prosthetic tooth function and patient comfort.
• Understanding the mechanical properties, such as creep, is essential for predicting material longevity and performance.
• Heat-polymerized and auto-polymerized acrylic resins are common denture base materials with potentially different creep behaviors.

Purpose of the Study:

• To investigate and compare the creep characteristics of heat-polymerized and auto-polymerized denture base materials.
• To correlate creep rates with processing conditions and material composition.
• To identify the underlying deformation mechanisms influencing creep behavior at various stress levels and temperatures.

Main Methods:

• Creep tests were conducted on heat-polymerized and auto-polymerized denture base materials at temperatures of 23, 37, and 50 degrees C.
• Secondary steady-state creep rates were measured and analyzed.
• Creep data were correlated with processing conditions and material composition, and deformation mechanisms were investigated under different stress levels.

Main Results:

• Heat-polymerized materials demonstrated the lowest secondary steady-state creep rates.
• Two distinct creep mechanisms were observed: homogeneous deformation at lower stress levels (< 20-40 MNm⁻² at 37°C) and inhomogeneous deformation at higher stress levels.
• Variations in creep rates among auto-polymerized materials were linked to differences in their composition.

Conclusions:

• Heat-polymerized denture base materials offer superior resistance to creep compared to auto-polymerized alternatives.
• Material composition and processing significantly impact creep resistance and deformation mechanisms in denture base resins.
• Understanding these factors is vital for selecting and processing optimal denture base materials for clinical applications.