Investigation of two types of denture disinfectant agents on micro-hardness and surface roughness of conventional heat cure acryl and Titanium Dioxide Nanoparticles boosted acryl

Abstract

Background and objective: Chemical agents are used for disinfecting dentures that are generally used along with mechanical methods. Researches have shown that chemical agents play a significant role in eliminating microorganisms and microbial plaques. However, they can cause physical and mechanical changes in acrylic resins including changes in color, micro-hardness and surface roughness. Over time, reduce in micro-hardness and increase in surface roughness increase the adhesion of microbial and food particles to the acrylic surface, which eventually leads to irritation and inflammation of the oral mucosa. Adding a weight amount of 1% Tio2 Nanoparticles to acryl can improve its properties. The objective of this study was to investigate the effect of two denture disinfectant agents on micro-hardness and surface roughness of conventional heat cure acryl and TiO2 nanoparticles boosted acryl.

Materials and methods: In this Invitro study, the samples included 60 acrylic specimens in 2 groups of 30, each group in 10 subtypes. Samples of dentures with heat cure acryl and acryl with 1% weight of Tio2 Nanoparticles were prepared and immersed in three solutions containing water, a solution prepared with Nature Dent pills, and sodium hypochlorite 1% for three periods of 30, 60 and 90 days.Each day, the antiseptic solution was replaced and this process was repeated. Then, the samples were washed with distilled water and placed in a special container filled with distilled water to make the storage condition uniform. After that, micro-hardness and surface roughness tests were performed on each sample during each stage. The obtained data were analyzed using descriptive statistical methods, two way ANOVA, one-way ANOVA, T-test and Tukey HSD test and analyzed using SPSS version 17 statistical software. In this study, p values less than 0.05 were considered significant.

Findings: In days 30, 60 and 90, micro-hardness in the water samples was significantly the highest amount (p> .05) and in the samples of Hypochlorite was significantly the lowest amount (p <.05) in both conventional and TiO2 1% boosted acryl. Micro-hardness was in the second place in Nature Dent samples (p <.05). Micro-hardness was significantly higher in TiO2 boosted acryl samples compared to conventional acryl (p <.05). A significant difference was seen in surface roughness by changing the type of resin on days 1, 30, 60 and 90 (p <.05). Changing the type of antiseptic did not alter surface roughness significantly on days 1, 30, and 60 (p> .05). However, on the 90th day, the difference was significant (p <.05). In addition, the results indicated that the amount of increase in sodium hypochlorite solution was higher than Nature Dent and the amount of change in surface roughness in acryl with 1% weight of titanium Nano-dioxide was less than conventional acryl.

Conclusion: Adding one percent powder of Tio2 Nanoparticles to heat cure acryl can increase the strength of denture to changes in micro-hardness and surface roughness against sodium hypochlorite and Nature Dent disinfectant tablet solutions. In addition, the effect of the type of disinfectant solution on micro-hardness and roughness increases over time. This effect is lower in Tio2 Nanoparticles boosted acryl compared to conventional heat cure acryl.