Publicação
Effect of thermal treatments on optical properties of bis-acryl resins
| Resumo: | Aim: The purpose of this study was to evaluate the effect of various thermal treatments on the chromatic stability of two bis-acrylic resins, after 24h and 7d. Materials and Methods: Ten experimental groups (n=10) were set according to the several possible combinations between the bis-acrylic resin (Protemp 4, P4; Structur 3, S3) and post-polymerization thermal treatment (without any post-polymerization treatment, nt; post-polymerization in a water bath at 60°C for 5 minutes, wb5; microwave at 750W for 1 minute, mw1; water bath at 60°C for 1 minute, wb1; conventional hairdryer for 1 minute, hd1). Thirty minutes after the polymerization, the baseline color values were measured, and all the specimens were immersed in the staining solution (coffee). After 24h and 7d new measurements were taken and ΔE calculated. A ΔE higher than 3.7 was considered clinically unacceptable. After confirming the normality and homogeneity of the data with Shapiro-Wilk and Levene’s testes (p>0.05), the ΔE data were submitted to a 2-way ANOVA, followed by 1-way ANOVA and Tukey post-hoc tests for each material (α=0.05). Results: The ΔE ranged between 5.9 and 13.0, at 24h, and between 9.1 and 24.7, after 7d. The ΔE was statistically (p<0.001) influenced by both bis-acrylic resin and post-polymerization heat treatment, at 24h and 7d. A statistically significant (p<0.001) interaction was observed between the two factors. At 24h, regarding S3 specimens, all post-polymerization treatments showed a statistically (p<0.05) higher ΔE than the nt group, but for the P4 specimens, the mw1 and wb5 groups showed similar (p>0.05) ΔE than nt group. At 7d, no differences were found between S3 groups. In the P4 specimens, the wb5 showed a lower ΔE than nt, and only the wb1 and the hd1 obtained a ΔE higher than nt. Conclusion: Both, bis-acrylic resin and post-polymerization treatments, influence the ΔE, at 24h and 7d. |
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| Autores principais: | Lourenço, Daniela Filipa Vala |
| Assunto: | Materiais dentários Resinas acrílicas Teses de mestrado - 2018 |
| Ano: | 2018 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | Aim: The purpose of this study was to evaluate the effect of various thermal treatments on the chromatic stability of two bis-acrylic resins, after 24h and 7d. Materials and Methods: Ten experimental groups (n=10) were set according to the several possible combinations between the bis-acrylic resin (Protemp 4, P4; Structur 3, S3) and post-polymerization thermal treatment (without any post-polymerization treatment, nt; post-polymerization in a water bath at 60°C for 5 minutes, wb5; microwave at 750W for 1 minute, mw1; water bath at 60°C for 1 minute, wb1; conventional hairdryer for 1 minute, hd1). Thirty minutes after the polymerization, the baseline color values were measured, and all the specimens were immersed in the staining solution (coffee). After 24h and 7d new measurements were taken and ΔE calculated. A ΔE higher than 3.7 was considered clinically unacceptable. After confirming the normality and homogeneity of the data with Shapiro-Wilk and Levene’s testes (p>0.05), the ΔE data were submitted to a 2-way ANOVA, followed by 1-way ANOVA and Tukey post-hoc tests for each material (α=0.05). Results: The ΔE ranged between 5.9 and 13.0, at 24h, and between 9.1 and 24.7, after 7d. The ΔE was statistically (p<0.001) influenced by both bis-acrylic resin and post-polymerization heat treatment, at 24h and 7d. A statistically significant (p<0.001) interaction was observed between the two factors. At 24h, regarding S3 specimens, all post-polymerization treatments showed a statistically (p<0.05) higher ΔE than the nt group, but for the P4 specimens, the mw1 and wb5 groups showed similar (p>0.05) ΔE than nt group. At 7d, no differences were found between S3 groups. In the P4 specimens, the wb5 showed a lower ΔE than nt, and only the wb1 and the hd1 obtained a ΔE higher than nt. Conclusion: Both, bis-acrylic resin and post-polymerization treatments, influence the ΔE, at 24h and 7d. |
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