Evaluation of rheological behaviour of flowable dental composites reinforced with low aspect ratio micro-sized glass fibres

Publication Name

Dental Materials

Abstract

Objective: Experimental investigation is carried out to determine the flowability and stickiness of the developed composite material for dental restoration containing low aspect ratio (AR ≤ 100) surface treated micro-sized glass fibres. Methods: Specimens are manufactured by mixing low AR (50/70/100) micro-sized glass fibres with two different weight fractions (5%/10%) into UDMA/TEGDMA based resin. Particulate filler composite (PFC) containing 55% glass fillers is used as the control group. Dynamic oscillatory strain sweep tests are conducted to analyse the linear viscoelastic behaviour. Solid-to fluidic transition behaviour of dental composites is also calculated in terms of flow and yield stresses. Furthermore, the oscillatory frequency sweep tests are conducted at three different strains (0.5%, 5% and 50%) resembling the positioning of unset paste onto restorations for different real-life clinical situations. Additionally, stickiness of dental composites with handling instrument (steel) and dentine covered with bonding agent is also evaluated. Results: The results suggested the all the FRC groups exhibited non-Newtonian, shear-thinning behaviour. It is further established that inclusion of 5% of 50/70AR fibres into dental composites does not affect the flowability. Simultaneously, stickiness with dentine covered with bonding agent is more for these two compositions as compared to that of handling instrument (steel). Significance: This study suggest that visco-elastic properties of dental composites are greatly affected by the type of filler (spherical shaped particulate fillers or rod-shaped fibres) as well as fibre weight fraction/fibre AR. This phenomenon can be attributed to the varying interactions between micro-sized fibres of different AR/weight fraction, particulate fillers and monomers.

Open Access Status

This publication is not available as open access

Volume

37

Issue

1

First Page

131

Last Page

142

Funding Number

CE140100036

Funding Sponsor

Australian Research Council

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Link to publisher version (DOI)

http://dx.doi.org/10.1016/j.dental.2020.10.023