August 2013, Volume 9, Issue 8
Published by AEGIS Communications
Why Use Bulk-Fill Flowable Composites?
Increase efficiency and mitigate risks with Surefil SDR flow
Today’s practitioner must effectively perform all required operative steps to successfully complete direct-composite resin restorations. If the steps (eg, isolation, adhesion, composite placement, and curing) are performed correctly, the risk of premature composite resin failure is mitigated. In addition, these steps must be completed with relative promptness to contend with issues such as practice overhead and low insurance reimbursement.
Efficiency in everyday dental practice should therefore be considered as not only the ability of the operator to work quickly, but also competently. As Ronald D. Jackson, DDS, recently wrote, “Given today’s overhead per hour, dentists need material and technology advancements so that posterior composites can be placed faster, easier, and profitably without taking compromising shortcuts.”1
The first flowable composite resin was introduced in 1996. Despite the long list of applications for flowable composite resins, these materials exhibit significant polymerization shrinkage and are not suitable to withstand occlusal wear.2 Recent advances in monomer technology have introduced a new category of bulk-fill flowable composites that are designed to address the shortcomings of earlier products’ materials. These new bulk-fill flowable composites promote the effective use of 4-mm increments while decreasing shrinkage stresses generated during polymerization.3,4 In 2009, the first bulk-fill flowable composite resin, Surefil® SDR® flow (DENTSPLY Caulk, www.caulk.com), was introduced. Table 1 shows the physical properties of Surefil SDRflow.
The organic resin matrix of Surefil SDR flow comprises a patent-registered urethane dimethacrylate with incorporated photoactive groups that are able to control polymerization kinetics. “Through the use of the ‘Polymerization Modulator,’ the resin forms a more relaxed network and provides significantly lower polymerization stress,” according to the manufacturer.5 A recent study compared Surefil SDR flow with 2 other composite resins and found that the contraction stress generated by Surefil SDR flow was 1.1 mPa, compared to 5.3 mPa and 6.5 mPa with Esthet-X® Flow Liquid Micro Hybrid (DENTSPLY Caulk) and Filtek™ Supreme Plus Flowable Restorative (3M ESPE, www.3m.com), respectively.6Because of the product’s lower filler content by volume (44% to 45%), the Surefil SDR flow directions for use recommend that a 2-mm occlusal cap be placed using a traditional composite restorative, such as TPH Spectra™ Universal Composite (DENTSPLY Caulk).7
The configuration factor (C-factor) is an estimation of the stresses generated by a given cavity configuration using the ratio of bonded to unbonded surfaces. According to Feilzer and colleagues,8 the higher the C-factor (ie, the greater the number of bonded surfaces), the higher the stress generated. Typically, Class 1 and 2 preparations have the largest C-factor and have the potential for producing the greatest polymerization stresses. If careful technique is not used to reduce polymerization stress, negative outcomes, such as postoperative sensitivity, microleakage, secondary caries, and adhesive debonding, can result.9-11
The use of bulk-fill flowable composites can reduce operator time during the placement of posterior composite resin restorations. In a study that examined the clinical crown heights of posterior teeth, it was determined that the average height was 8 mm in first premolars and 4 mm in second molars.12 With the ability to bulk fill in 4-mm increments and then place a 2-mm occlusal cap, dentists can reduce the number of increments needed to restore Class 1 and 2 preparations without additional shrinkage stress or loss of marginal quality.13
In contrast to Surefil SDR flow, more viscous bulk-fill materials are also available in the United States. These bulk-fill restorative composites can be used to restore occlusal surfaces and have a published depth of cure of 4 to 6 mm; examples include Alert® Condensable Composite (Pentron, www.pentron.com), Tetric EvoCeram® Bulk Fill (Ivoclar Vivadent Inc., www.ivoclarvivadent.us), and x-tra fil (Voco, www.voco.com). A January 2012 Clinicians Report by Christensen3 points out a potential disadvantage of bulk-fill restorative composites, as the examples mentioned were found to be associated with the frequent presence of voids. Surefil SDR flow was found to have a lower maximum stress rate than the bulk-fill restorative composites, and was associated with the presence of only occasional voids.3
A 46-year-old woman presented for removal of a mesio-occlusal amalgam on tooth No. 30 and replacement with composite resin (Figure 1). After verifying the patient’s medical history and examining her radiographs, the area was anesthetized with 1 carpule of 4% Articadent™ DENTAL with epinephrine 1:100,000 (DENTSPLY Pharmaceutical, www.dentsplypharma.com). The preparation was completed with high-speed (330-bur) and low-speed (4-round bur) handpieces, making sure that residual amalgam stain was removed (Figure 2). After verifying caries removal with Snoop Caries Detecting Dye (Pulpdent Corporation, www.pulpdent.com), a rubber dam was placed to isolate the tooth before restoration.
A BiTine™ matrix (DENTSPLY International, www.dentsply.com) was placed and then wedged interproximally to isolate the preparation. Because of the shallow preparation, a total-etch technique was used with Prime&Bond Elect™ universal dental adhesive (DENTSPLY Caulk). The preparation was etched with 34% phosphoric acid for 15 seconds and then rinsed. Prime&Bond Elect universal dental adhesive was scrubbed into the preparation for 20 seconds, followed by a 5-second air-dry to remove the solvent. Surefil SDR flow was placed throughout the entire preparation as a first layer to within 2 mm of the occlusal cavosurface (Figure 3). By using Surefil SDR flow as an initial layer in depths up to 4 mm, excellent cavity adaptation was achieved with low polymerization stress. The final layer was completed with TPH Spectra Universal Composite High Viscosity shade A3. The final restoration was shaped with plastic composite instruments and fluted finishing burs on high speed. To achieve final luster after occlusal adjustment, Enhance® Finishing System (DENTSPLY International) and PoGo™ One Step Diamond Micro-Polishers (DENTSPLY International) were used on a low-speed handpiece (Figure 4).
With the use of Surefil SDR flow, dentists can increase efficiency by placing fewer increments of material. Coupled with improved monomer technology designed to reduce polymerization stress, use of bulk-fill flowable composites when performing posterior Class 1 and 2 restorations provides benefits, such as low stress and outstanding cavity adaptation, and helps the dentist avoid negative outcomes, such as postoperative sensitivity, microleakage, and debonding.
Clinical photographs are courtesy of Dr. Jürgen Manhart (Munich, Germany).
Jason H. Goodchild, DMD, is an employee of DENTSPLY Caulk.
1. Jackson RD. Placing posterior composites: increasing efficiency. Dent Today. 2011;30(4):126-131.
2. Bayne SC, Thompson JY, Swift EJ, et al. A characterization of first-generation flowable composites. J Am Dent Assoc. 1998;129(5):567-577.
3. Christensen GJ. Advantages and challenges of bulk-fill resins. Clinicians Report. 2012;5(1):1-6.
4. SureFil® SDR™ flow Posterior Bulk Fill Flowable Base. Inside Dentistry. 2009;5(9):124.
5. Surefil® SDR® flow. DENTSPLY Caulk website. www.surefilsdrflow.com. Accessed March 28, 2013.
6. Ilie N, Hickel R. Investigations on a methacrylate-based flowable composite based on the SDR™ technology. Dent Mater. 2011;27(4):348-355.
7. Surefil® SDR® flow [directions for use]. Milford, DE: DENTSPLY Caulk; 2012. www.surefilsdrflow.com/sites/default/files/SureFil_DFU.pdf/. Accessed March 28, 2013.
8. 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.
9. 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.
10. 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 Rest Dent. 1996;4(1):29-33.
11. Roggendorf MJ, Krämer N, Appelt A, et al. Marginal quality of flowable 4-mm base vs. conventionally layered resin composite. J Dent. 2011;39(10):643-647.
12. Volchansky A, Cleaton-Jones P. Clinical crown height (length)—a review of published measurements. J Clin Periodontol. 2001;28(12):1085-1090.
13. 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.
About the Author
Jason H. Goodchild, DMD
Clinical Associate Professor
Department of Oral Medicine
University of Pennsylvania School of Dental Medicine
Research Dentist, Clinical Research and Education