Water sorption of plasticized denture acrylic lining materials

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Denture acrylic lining materials are susceptible to water sorption, affecting their mechanical properties and longevity.
• Understanding water diffusion and uptake is critical for developing more stable and durable denture base materials.

Purpose of the Study:

• To characterize the water sorption behavior, including uptake and diffusion coefficients, of plasticized denture acrylic lining materials.
• To investigate the influence of phthalate plasticizers on the water sorption properties of poly(methyl methacrylate) (PMMA).

Main Methods:

• Preparation of plasticized PMMA by radiation polymerization of methyl methacrylate/plasticizer solutions.
• Water desorption measurements were used to determine water uptake and diffusion coefficients (D).
• Characterization of proprietary denture materials for glass transition temperature (Tg) and composition.

Main Results:

• Plasticizers were found to decrease water uptake in PMMA, attributed to their hydrophobic nature and microvoid filling.
• Diffusion coefficients (D) increased monotonically with increasing plasticizer volume fraction.
• The rate of increase in D was more pronounced when plasticizer content raised the material above its glass transition temperature (Tg).

Conclusions:

• Phthalate plasticizers significantly alter the water sorption characteristics of PMMA-based denture materials.
• The findings provide insights into optimizing denture material formulations for reduced water absorption and controlled diffusion.
• Further characterization of commercial materials confirmed the observed trends, highlighting the importance of plasticizer content and Tg.