Inside Dentistry
October 2014
Volume 10, Issue 10

Surefil® SDR® flow

Bulk filling with low polymerization stress

Shrinkage of flowable composites can compromise the success of the restoration and contribute to a poor marginal seal, microleakage, deformation of the tooth, microfracture, and recurrent caries.1 If the flowable resin is placed into a confined space, and then shrinks during polymerization, stress will develop. Several factors have been identified as influencing shrinkage stress: the size and geometry of the restoration, materials used, and the curing protocol.2,3

Recent advances in monomer technology have ushered a new category of bulk-fill flowable composites designed to address material shortcomings of earlier products. The new category of bulk-fill flowable composites promote the effective use of 4-mm increments while decreasing shrinkage stresses generated during polymerization.4

In 2009, DENTSPLY Caulk introduced the first bulk-fill flowable resin, Surefil® SDR® flow with excellent cavity adaptation and self-leveling handling. The organic resin matrix of Surefil SDR flow comprises a patent-registered urethane dimethacrylate with incorporated photoactive groups able to control polymerization kinetics. In a 2012 Clinicians Report, Surefil® SDR® flow was shown to have the lowest polymerization stress among the bulk-fill flowable resins tested.4

C-factor is an estimation of the stresses generated through a given cavity configuration by a ratio of bonded to unbonded surfaces. The higher the C-factor (ie, the higher the number of bonded surfaces), the higher the stress generated (eg. Class I and II). Conversely, a cavity with a higher ratio of unbonded surfaces should result in lower shrinkage stress (eg, Class III and IV).5 Two recent studies have also suggested that cavity depth and diameter may impact shrinkage stress and resulting microleakage.6,7 Examining the effect of bulk-filling high C-factor cavities with a low shrinkage flowable composite (Surefil SDR flow), it was shown that 4-mm increments placed in high C-factor preparations did not compromise bond strength secondary to shrinkage stress.8,9 The authors concluded that if bulk-fill techniques are desired for restoration of high C-factor cavities, the dentist should consider low-stress materials to avoid adhesive de-bonding and microleakage.

In another study, cuspal deflection and tooth deformation in Class II preparations were examined.10 The authors compared a conventional resin-based composite with Surefil SDR flow low-stress bulk-fill flowable composite. After restoration, cuspal deflection was measured and found to be reduced by greater than 50% when Surefil SDR flow used. The authors suggest that bulk-filling to within 2-mm of the occlusal cavosurface can reduce operator time because of reduced incremental layers without additional shrinkage stress or loss of marginal quality.


1. Margolis FS. Flowable composites: aesthetics for tots and teens. Dent Today. 2011;30(4):132-137.

2. Malhotra N, Kundabala M, Shashirashmi A. Strategies to overcome polymerization shrinkage--materials and techniques. A review. Dent Update. 2010;37(2):115-125.

3. Xavier JC, de Melo Monteiro GQ, Resende Montes MAJ. Polymerization shrinkage and flexural modulus of flowable dental composites. Materials Research. 2010;13(3):381-384.

4. Advantages and challenges of bulk-fill resins. Clinicians Report. 2012;5(1):1-6.

5. Feilzer AJ, De Gee AJ, Davidson CL. Setting stress in composite resin in relation to configuration of the restoration. J Dent Res. 1987;66(11):1636-1639.

6. Braga RR, Boaro LC, Kuroe T, et al. Influence of cavity dimensions and their derivatives (volume and ‘C’ factor) on shrinkage stress development and microleakage of composite restorations. Dent Mater. 2006;22(9):818-823.

7. Watts DC, Satterthwaite JD. Axial shrinkage-stress depends upon both C-factor and composite mass. Dent Mater. 2008;24(1):1-8.

8. Van Ende A, De Munck J, Van Landuyt KL, et al. Bulk-filling of high C-factor posterior cavities: effect on adhesion to cavity-bottom dentin. Dent Mater. 2013;29(3):269-277.

9. de la Macorra JC, Gomez-Fernandez S. Quantification of the configuration factor in Class I and II cavities and simulated cervical erosions. Eur J Prosthodont Restor Dent. 1996;4(1):29-33.

10. Moorthy A, Hogg CH, Dowling AH, et al. Cuspal deflection and microleakage in premolar teeth restored with bulk-fill flowable resin-based composite base materials. J Dent. 2012;40(6):500-505.

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