Journal List > J Korean Acad Conserv Dent > v.34(2) > 1056348

Lee, Min, Kim, Cho, and Back: Slumping tendency and rheological property of flowable composites

Abstract

The aim of this study was to develop a method for measuring the slumping resistance of flowable resin composites and to evaluate the efficacy using rheological methodology.
Five commercial flowable composites (Aelitefil flow:AF, Filtek flow:FF, DenFil flow:DF, Tetric flow:TF and Revolution:RV) were used. Same volume of composites in a syringe was extruded on a glass slide using a custom-made loading device. The resin composites were allowed to slump for 10 seconds at 25℃ and light cured. The aspect ratio (height/diameter) of cone or dome shaped specimen was measured for estimating the slumping tendency of composites. The complex viscosity of each composite was measured by a dynamic oscillatory shear test as a function of angular frequency using a rheometer. To compare the slumping tendency of composites, one way-ANOVA and Turkey's post hoc test was performed for the aspect ratio at 95% confidence level. Regression analysis was performed to investigate the relationship between the complex viscosity and the aspect ratio. The results were as follows.
1. Slumping tendency based on the aspect ratio varied among the five materials (AF < FF < DF < TF < RV).
2. Flowable composites exhibited pseudoplasticity in which the complex viscosity decreased with increasing frequency (shear rate). AF was the most significant, RV the least.
3. The slumping tendency was strongly related with the complex viscosity. Slumping resistance increased with increasing the complex viscosity.
The slumping tendency could be quantified by measuring the aspect ratio of slumped flowable composites. This method may be applicable to evaluate the clinical handling characteristics of flowable composites.

Figures and Tables

Figure 1
Schematic diagram of composite loading device.
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Figure 2
a) Lateral view of cured flowable composites after slumping for 10 s at 25℃. b) Aspect ratio (height/base diameter) of cured slumped composite was measured to compare the slumping tendency among composites.
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Figure 3
Aspect ratio of slumped flowable composites. Higher aspect ratio means that the material has higher slumping resistance.
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Figure 4
Representative curves of complex viscosity of composites as a function of angular frequency in a dynamic oscillatory shear - frequency sweep test. The viscosity very rapidly decreased with increasing frequency (a: logarithmic plot, b: linear plot).
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Figure 5
Regression analysis showed that the aspect ratio of composites as a function of complex viscosity η*ω=0.1 rad/s is well fitted to a nonlinear curve y=ln(a+bx)(y: aspect ratio, x: complex viscosity η*) (R=0.978).
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Table 1
The flowable resin composites used in this study.
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Table 2
Post-slumped aspect ratio and complex viscosities at varying oscillation frequency of flowable composites.
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Different superscripts mean that there is statistically significant difference (P<0.05).

References

1. Bayne SC, Thompson JY, Swift EJ, Stamatiades P, Wilkerson M. A characterization of first generation-flowable composites. J Am Dent Assoc. 1998. 129:567–577.
2. Craig RG, Powers JM. Restorative dental materials. 2002. 11th Ed. Mosby Co;91–98. 231–251.
3. Lee IB, Son HH, Um CM. Rheological properties of flowable, conventional hybrid, and condensable composite resins. Dent Mater. 2003. 19:298–307.
crossref
4. Summitt JB, Robbins JW, Hilton TJ, Schwartz RS. Fundamentals of operative dentistry: A contemporary approach. 2006. 3rd Ed. Quintessence books;319–323.
5. Jackson RD, Morgam M. The new posterior resins and a simplified placement technique. JADA. 2000. 131:375–383.
6. Leinfelder KF, Radz GM, Nash RW. A report on a new condensable composite resin. Compendium. 1998. 19(3):230–237.
7. Al-Sharaa KA, Watts DC. Stickiness prior to setting of some light cured resin composites. Dent Mater. 2003. 19:182–187.
8. Lee IB, Chang J, Ferracane J. Slumping resistance and viscoelasticity prior to setting of dental composites. Dent Mater. 2008. 24:1586–1593.
crossref
9. Opdam NJM, Roeters JJM, Peters TCRB, Burgersdijk RCW, Kuijs RH. Consistency of resin composites for posterior use. Dent Mater. 1996. 12:350–354.
crossref
10. Tyas MJ, Jones DW, Rizkalla AS. The evaluation of resin composite consistency. Dent Mater. 1998. 14:424–428.
crossref
11. Lee IB, Cho BH, Son HH, Um CM. Rheological characterization of composites using a vertical oscillation rheometer. Dent Mater. 2006. 23:425–432.
crossref
12. Beun S, Bailly C, Devaux J, Leloup G. Rheological properties of flowable resin composites and pit and fissure sealants. Dent Mater. 2008. 24:548–555.
crossref
13. The Korean society of rheology. Rheology and its application. 2001. 1st Ed. 3–103. 175–91.
14. Barnes HA, Hutton JF, Walters K. An introduction to rheology. 1989. 1st Edi. Elsevier Science Publishing Co;64–73.
15. Lee JH, Um CM, Lee IB. Rheological properties of resin composites according to variations in monomer and filler composition. Dent Mater. 2006. 22:515–526.
crossref
16. Kim SW, Kim OY, Jang JS. Rheological properties of fumed silica filled Bis-GMA dispersions. Polym Eng Sci. 1998. 38:1142–1148.
crossref
17. Ellakwa A, Cho N, Lee IB. The effect of resin matrix composition on the polymerization shrinkage and rheological properties of experimental dental composites. Dent Mater. 2007. 23:1229–1235.
crossref
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