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. 2016 Jul-Sep;7(3):307-11.
doi: 10.4103/0976-237X.188543.

Effect of nanoscale particles incorporation on microhardness of polymers for oral prosthesis

Marcelo Coelho Goiato  1 , Bruna Carolina Rossatti Zuccolotti  1 , Amalia Moreno  2 , Aljomar José Vechiato Filho  1 , Marcela Borghi Paulini  1 , Daniela Micheline Dos Santos  1
Affiliations

Effect of nanoscale particles incorporation on microhardness of polymers for oral prosthesis

Marcelo Coelho Goiato et al. Contemp Clin Dent. 2016 Jul-Sep.

Abstract

Objectives: This study aimed to evaluate the influence of the incorporation of pigments on surface hardness of four acrylic resins subjected to thermocycling and analyze their elemental composition using energy dispersive X-ray spectroscopy (EDS).

Materials and methods: Twenty-one discs of each resin were fabricated, whereas seven had no additive, seven had 3% of nanoscale pigments and last seven had 10% of them. The percentage was obtained by measuring the total weight of each resin disc. Besides, seven discs composed by only nanoscale pigments were also fabricated, totalizing 91 discs. The pigment was weighed by using an analytical balance (BEL Analytical Equipment, SP, Brazil). The surface hardness was measured through a hardness tester machine before and after thermocycling (5-55°C, for 2000 cycles). Data were analyzed by ANOVA and Tukey's test (P < 0.05). The chemical composition of the discs composed only by nanoscale pigments was analyzed with EDS test.

Results: Hardness of all resins decreased after thermocycling. The lowest values were observed on the discs with 3% of nanoscale pigments and discs fabricated only with them. EDS showed the presence of titanium dioxide.

Conclusion: Discs with 7% of pigments (after thermocycling) showed higher hardness values.

Keywords: Acrylic resins; denture bases; geriatrics.

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Figures

Figure 1
Figure 1
Average values of hardness for each period, regardless of pigment and resin used. *Lowercase letters between the different resins indicates statistically significant difference between periods (P < 0.05)
Figure 2
Figure 2
Mean results of Knoop microhardness for each resin at different pigment concentrations, regardless the period of evaluation. *Only the specimens with 3% of pigmentation concentration from the resin QC-20 showed statistically significant difference compared to the other specimens of the same resin brand
Figure 3
Figure 3
Energy dispersive X-ray spectroscopy/MEV image of the pigment powder
See this image and copyright information in PMC

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