Comparative Evaluation of Water Sorption of Heat-Polymerized Polymethyl Methacrylate Denture Base Resin Reinforced...

Polymethyl methacrylate (PMMA) is the most regularly used material in denture fabrication. Water sorption of denture base PMMA denture base resin has negative effects on physical properties, may lead to harmful tissue reactions in patients, and also has detrimental effects on color stability of the denture base.

The purpose of this study was to evaluate the effect on water sorption of heat-cured PMMA denture base material after incorporation of 1%, 3%, and 5% by weight of silanized titanium dioxide (TiO₂) nanoparticles.

For preparation of test samples, TiO₂ nanoparticles (PCode: 700339, Sigma-Aldrich, USA) were coated with a layer of trimethoxysilylpropylmethacrylate (PCode: 440159, Sigma-Aldrich, USA) before sonicated in monomer (MMA) (DPI Heat Cure) with the percentages 1%, 3%, and 5% by weight; after sonication, it was mixed with PMMA powder using conventional denture fabrication procedure. Then, we prepared total 40 samples for study; 10 samples for each four groups, i.e. that is one control group and three experimental groups. The first group was prepared from PMMA without addition of TiO₂ nanoparticles (control group), the second group with the addition of 1 wt% TiO₂ nanoparticles, the third group with 3 wt% TiO₂ nanoparticles, and the fourth one with 5 wt% TiO₂ nanoparticles (experimental groups). Water sorption test was then conducted on each sample.

Each group was evaluated for water sorption test, and it was found that increasing the wt% of nanoparticles, there was a significant decrease in water sorption of denture base resin from 1.74 to 1.46 mean wt%. P value suggested that the difference of mean percent increase across all groups was statistically significant with P = 0.034.

The maximum decrease in water sorption was observed in denture base resin incorporated with 5 wt% TiO₂ nanoparticles.