Network structures of Bis-GMA/TEGDMA resins differ in DC, shrinkage-strain, hardness and optical properties as a function of reducing agent

Adilson Y. Furuse, José Mondelli, David C. Watts

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Objectives: To evaluate the influence of different tertiary amines on degree of conversion (DC), shrinkage-strain, shrinkage-strain rate, Knoop microhardness, and color and transmittance stabilities of experimental resins containing BisGMA/TEGDMA (3:1 wt), 0.25 wt% camphorquinone, 1 wt% amine (DMAEMA, CEMA, DMPT, DEPT or DABE). Different light-curing protocols were also evaluated. Methods: DC was evaluated with FTIR-ATR and shrinkage-strain with the bonded-disk method. Shrinkage-strain-rate data were obtained from numerical differentiation of shrinkage-strain data with respect to time. Color stability and transmittance were evaluated after different periods of artificial aging, according to ISO 7491:2000. Results were evaluated with ANOVA, Tukey, and Dunnett's T3 tests (α = 0.05). Results: Studied properties were influenced by amines. DC and shrinkage-strain were maximum at the sequence: CQ <DEPT <DMPT ≤ CEMA ≈ DABE <DMAEMA. Both DC and shrinkage were also influenced by the curing protocol, with positive correlations between DC and shrinkage-strain and DC and shrinkage-strain rate. Materials generally decreased in L* and increased in b*. The strong exception was the resin containing DMAEMA that did not show dark and yellow shifts. Color varied in the sequence: DMAEMA <DEPT <DMPT <CEMA <DABE. Transmittance varied in the sequence: DEPT ≈ DABE <DABE ≈ DMPT ≈ CEMA <DMPT ≈ CEMA ≈ DMAEMA, being more evident at the wavelength of 400 nm. No correlations between DC and optical properties were observed. Significance: The resin containing DMAEMA showed higher DC, shrinkage-strain, shrinkage-strain rate, and microhardness, in addition to better optical properties. © 2011 Academy of Dental Materials.
    Original languageEnglish
    Pages (from-to)497-506
    Number of pages9
    JournalDental Materials
    Volume27
    Issue number5
    DOIs
    Publication statusPublished - May 2011

    Keywords

    • Amines
    • Bis-GMA
    • Color-stability
    • Methacrylates
    • Resin-composites
    • Shrinkage-strain

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