Class III Direct Restoration with Flowable Bulk-fill Composite
Newer materials offer improved strength and esthetics when access is limited
Robert A. Lowe, DDS
Placement of physiologically contoured, esthetic Class III composite restorations can be a deceivingly difficult procedure. Oftentimes, these types of lesions present with limited clinical access, making traditional paste composites tough to place without creating marginal voids. Although flowable composites are better suited for this task due to their ease of placement, their use becomes limited when the depth of the preparation is greater than 2 mm from the facial to the lingual aspects.1 With all parameters being "ideal," a bulk-fill flowable resin may be perfectly suited to restore these types of lesions, as long as it can produce the desired esthetic result. Bulk-fills have been used clinically for several years and are traditionally designed as a "dentin replacement," requiring an additional material to be used for the "enamel layer" to handle occlusal wear or achieve higher quality esthetics in the anterior region.2 Because flowable bulk-fills are lower viscosity materials when compared with conventional "paste" composites, this use has also been shown to increase marginal adaptation in the line angles and point angles of preparations, thereby reducing the potential for marginal failure from microleakage.3,4 Some of the newer bulk-fill flowable composites on the market do not require a capping layer of another composite for strength and are more opacious, which results in better anterior esthetics.
A patient presented with a Class III distal composite restoration in tooth No. 7 (Figure 1) with evidence of marginal leakage that was in need of replacement. After a guard (WedgeGuard, Ultradent Products) was placed to protect the adjacent surface, the composite material and any existing recurrent decay were removed using a 330-carbide bur (SS White) (Figure 2). A super-pulsed diode laser (Gemini®, Ultradent Products) was used to perform a gingivoplasty, making the margin of the preparation supragingival for easier matrix placement and a better seal. Next, the preparation was selectively etched at the periphery of the enamel using 37% phosphoric acid for 15 seconds and rinsed with water. The enamel was air-dried, then a bonding agent (Tokuyama Universal Bond, Tokuyama Dental America) was placed on both the enamel and the dentin using a microbrush (Figure 4). This bonding agent is self-curing, so no curing light is necessary.
After placement of a wedge (Dual-Force Wedge, Clinician's Choice) and a suitable matrix (DC203, Bioclear) (Figure 5), a bulk-fill flowable composite (Estelite Bulk Fill Flow [shade A2], Tokuyama Dental America) was syringed into the preparation (Figure 6). A sable brush can be used to gently remove any excess material and ensure that the margins are covered. Because this bulk-fill does not require a capping layer, the preparation was completely filled to the cavosurface margin and to the top of the matrix band in the interproximal area. It is necessary to emphasize the importance of a properly fitted anatomic matrix to limit the amount of excess material as it is placed into the preparation. The goal should be to perform as little rotary finishing and contouring as possible.
After light curing the composite per the manufacturer's instructions, the matrix system was removed, and the finishing process was initiated using composite finishing carbide burs. The centric contacts were checked with articulating paper and adjusted, as needed. Next, the restoration was polished using rubber composite polishing instruments (A.S.A.P. All Surface Access Polishers, Clinician's Choice), and interproximal finishing instruments (ContacEZ Restorative Strip System, ContacEZ) were used to remove any excess resin bonding material and refine the interproximal contours as needed to ensure that dental floss could pass cleanly through the contact area. The restorative material blended nicely with the surrounding tooth structure, and an extremely high luster was achieved (Figure 7 and Figure 8).
For many years, it has been a goal to develop composite restorative materials that facilitate a more simplified, less technique-laden approach to clinical placement. A bulk-fill flowable composite offers the benefit of accurate adaptation to the preparation while eliminating the need for incremental placement and condensation (ie, plugging). The addition of spherical fillers with an average size of 200 nanometers optimizes the physical properties and esthetics of this bulk-fill material. This, combined with its high polishability and shade-matching ability, makes it a high-quality restorative option for a variety of clinical applications.
1. 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.
2. Flury S, Hayoz S, Peutzfeldt A, et al. Depth of cure of resin composites: is the ISO 4049 method suitable for bulk fill materials? Dent Mater. 2012;28(5):521-528.
3. Ilie N, Bucuta S, Draenert M. Bulk-fill resin-based composites: an in vitro assessment of their mechanical performance. Oper Dent. 2013;38(6):618-625.
4. Gupta R, Tomer AK, Kumari A, et al. Bulk fill flowable composite resins - a review. International Journal of Applied Dental Sciences. 2017;3(2):38-40.
About the Author
Robert A. Lowe, DDS
American Board of Aesthetic Dentistry
Charlotte, North Carolina