Effect of experimental heat treatment on mechanical properties of resin composites

• Autor(es):

  Santana, Ivone L. (Federal University of Maranhão. Dental School. Department of Restorative Dentistry);

  Lodovici, Edméa (University of São Paulo. Dental School. Department of Dental Materials);

  Matos, Jivaldo R. (University of São Paulo. Institute of Chemistry. Department of Fundamental Chemistry);

  Medeiros, Igor S. (University of São Paulo. Dental School. Department of Dental Materials);

  Miyazaki, Caroline L. (University of São Paulo. Dental School. Department of Dental Materials);

  Rodrigues-Filho, Leonardo E. (University of São Paulo. Dental School. Department of Dental Materials).

• Fonte:

  Brazilian Dental Journal; volume 20, número 3, páginas 205-210. 2009.

• Assuntos:

  composite resins;

  heat treatment;

  flexural strength;

  hardness.

• Resumo:

  The aim of this study was to verify the influence of an experimental heat treatment (170ºC/10 min) using a casting furnace on the mechanical properties (hardness and flexural strength) of 2 commercial direct resin composites (TPH Spectrum and Filtek P60) compared to a commercial indirect resin system (BelleGlass). Heat treatment temperature was determined after thermal characterization by thermogravimetry (TG) and differential scanning calorimetry (DSC). Data was analyzed by ANOVA and Tukey's test at 5% significance level. There was statistical significance for the main factor heat treatment (p=0.03) and composite (p=0.02), for flexural strength. For Knoop hardness, only the main factor composite was statistically significant (p=0.00). P60 presented higher hardness than TPH. No statistically significant correlation between mechanical properties tested was detected. Based on these results, it was possible to conclude that heat treatment influenced flexural strength of direct composites, while it was not observed for hardness. The association of direct composites with a simple post-cure heat treatment may be an alternative for current indirect composite systems, although more studies are needed to verify other properties of the composites for this application.

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