Influence of Irradiation Time on Volumetric Shrinkage and Flexural Properties of Flowable Resins

Abstract

The purpose of this study was to evaluate the influence of irradiation time on volumetric change and flexural properties of flowable resins. Four commercially available flowable resins were employed. For volumetric shrinkage measurement, resin pastes were inserted into a mold (2 mm in height, 4 mm in diameter) and put into a water-filled dilatometer. This was followed by light irradiation for 10, 20, or 30 seconds at 600 mW/cm 2 . Volumetric shrinkage of the specimens was then determined from the change in the height of water meniscus, and the percentage volumetric change thereof was calculated. For flexural strength measurement, resin pastes were filled into a stainless steel mold (25×2×2 mm), and the middle one-third of the specimen was first irradiated. The remaining two-thirds were irradiated under the same irradiation conditions as volumetric shrinkage measurement. After 24-hour storage in 37℃ water, three-point flexural tests were performed with a span length of 20 mm at a crosshead speed of 1.0 mm/min. One-way ANOVA followed by Tukey' s HSD test were used for statistical analysis. For all materials tested except Estelite Flow Quick, both volumetric shrinkage and flexural strength increased with longer light irradiation time. Results of this study indicated that both volumetric shrinkage and flexural properties were influenced by light irradiation time and resin composite type.

Dimensional change measurements of conventional and flowable composite resins using a laser displacement sensor

“…In a previous study 13) , the linear dimensional changes of the same flowable composite resins ranged from -1.00% to -1.24% -which were much smaller than those obtained in the present study. This disparity could be caused by the shorter irradiation time and measuring time employed in the previous study 13) .…”

“…In a previous study 13) , the linear dimensional changes of the same flowable composite resins ranged from -1.00% to -1.24% -which were much smaller than those obtained in the present study. This disparity could be caused by the shorter irradiation time and measuring time employed in the previous study 13) . On the other hand, by means of digital video image analysis method 14) , larger values were obtained: -0.6% to -1.3% for conventional composites, -1.2% to -2.0% for flowable composites, and -2.3% to -4.7% for filled adhesives.…”

Real-Time Imaging of Gap Progress during and after Composite Polymerization

“…The compositions of more recent low-viscosity composites have been modified in terms of monomer characteristics, polymerization initiators, and filler shape and surface treatment. The current flowable composite employs a radical amplifier polymerization initiator that has been reported to increase the pregel phase polymerization rate but reduce postgel shrinkage (Uyama et al 2007).…”

Large-proportional shrunken bio-replication of shark skin based on UV-curing shrinkage

“…It has become a hot research spot to study the shrinkage of UV-curable material; however there are few papers that deal with the positive uses of the shrinking effect. Almost all of the current studies focus on how to reduce the shrinkage of UV-curable materials, such as reducing the shrinkage by means of low-temperature [24], more illumination time [25], low light intensity [26], changing the composition of the UV-curable material [27] and other methods [28][29][30][31]. There is still no literature about the control of the UV-curable material shrinkage to adjust to the complex 3D microstructure.…”