Sonam Behl1, Abbas Darestani Farahani2, Ginu Rajan3, Ayman Ellakwa4, Paul Farrar5, Pall Thordarson6, B Gangadhara Prusty7. 1. School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW, 2052, Australia. Electronic address: sonam.kamboj@student.unsw.edu.au. 2. School of Chemistry, University of New South Wales, Sydney, NSW, 2052, Australia. Electronic address: a.darestanifarahani@unsw.edu.au. 3. School of Electrical, Computer & Telecommunications Engineering, University of Wollongong, Wollongong, NSW, 2522, Australia. Electronic address: ginu.uow@edu.au. 4. Prosthodontics and Oral Rehabilitation, School of Dentistry, University of Sydney, Sydney, NSW, 2010, Australia. Electronic address: ayman.ellakwa@sydney.edu.au. 5. SDI Limited, Bayswater, VIC, 3153, Australia. Electronic address: paul.farrar@sdi.com.au. 6. School of Chemistry, University of New South Wales, Sydney, NSW, 2052, Australia. Electronic address: p.thordarson@unsw.edu.au. 7. School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW, 2052, Australia; ARC Centre for Automated Manufacture of Advanced Composites, School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW 2052, Australia. Electronic address: g.prusty@unsw.edu.au.
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.
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.