Hygroscopic dimensional changes of self-adhering and new resin-matrix composites during water sorption/desorption cycles

Yong Jie Wei, Nick Silikas, Zhen Ting Zhang, David C. Watts

    Research output: Contribution to journalArticlepeer-review


    Objectives: To study hygroscopic dimensional changes in new resin-matrix composites during water sorption/desorption cycles. Methods: Five materials were examined: a self-adhering flowable composite: Vertise® Flow (VF), a universal composite: GC Kalore (GCK), two micro-fine hybrid composites: GC Gradia Direct Anterior (GDA) and GC Gradia Direct Posterior (GDP), and a posterior restorative composite: Filtek® Silorane (FS). Five disk-shaped specimens of each material were prepared (15 mm diameter × 2 mm thickness) according to ISO 4049. The mean diameter of each specimen was measured by a custom-built laser micrometer (to a resolution of 200 nm) periodically over 150 d water immersion and 40 d recondition periods at (37 ± 1) °C. Perspex controls were used. Data analysis was performed by repeated measures ANOVA, one-way ANOVA and Tukey's post hoc test (p <0.05). Results: Differences in hygroscopic expansion were found for all test materials during sorption, ranging from 0.74% (±0.05) for FS to 4.82% (±0.13) for VF. The differences were significant for all materials (p <0.001), except between GCK and GDA. The mathematical relationship between diametral expansion and square root of time was non-linear. VF exhibited significant dehydration shrinkage. Significance: The silorane composite FS had the lowest hygroscopic expansion. The extent of compensation of polymerization shrinkage by hygroscopic expansion depends on materials, specimen dimensions and time-scale. So the clinical situation must be taken into consideration in the application of these findings. © 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
    Original languageEnglish
    Pages (from-to)259-266
    Number of pages7
    JournalDental Materials
    Issue number3
    Publication statusPublished - Mar 2011


    • Dental resin-matrix composites
    • Desorption
    • DX-511
    • GPDM
    • Hygroscopic expansion
    • Self-adhering
    • Shrinkage
    • Silorane
    • UDMA
    • Water sorption


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