Yong-jie Wei1, Nick Silikas, Zhen-ting Zhang, David C Watts. 1. Department of Prosthodontics, School of Stomatology, Capital Medical University, Tiantan Xili No. 4, Chongwen District, Beijing 100050, PR China.
Abstract
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 150d water immersion and 40d 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.
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 150d water immersion and 40d 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.
Authors: Michael D Weir; Jennifer L Moreau; Eric D Levine; Howard E Strassler; Laurence C Chow; Hockin H K Xu Journal: Dent Mater Date: 2012-03-18 Impact factor: 5.304
Authors: Ke Zhang; Fang Li; Satoshi Imazato; Lei Cheng; Huaibing Liu; Dwayne D Arola; Yuxing Bai; Hockin H K Xu Journal: J Biomed Mater Res B Appl Biomater Date: 2013-03-26 Impact factor: 3.368
Authors: Lin Wang; Xianju Xie; Michael D Weir; Ashraf F Fouad; Liang Zhao; Hockin H K Xu Journal: J Mater Sci Mater Med Date: 2016-10-03 Impact factor: 3.896