A Posterior Sectional Matrix System to Save the Day
Donald B. Cork, DDS, on the DualForce™ Sectional Matrix System by Brasseler USA
The clinical challenges related to placing Class II direct composite restorations in the posterior environment are quite notorious. Maintaining isolation and creating an acceptable restoration can become more daunting at every turn, and the variation in preparation design required by the individual tooth anatomy, existence of prior restorations, presence of recurrent decay, and variability in occlusal forces can make this task even more challenging. For many seasoned practitioners, our initial attempts in this arena were challenged even further by the fact that the only posterior matrix available at the time was a stiff metal matrix band set in a Tofflemire holder, which was held in place with a rigid triangular-shaped wooden wedge. These metal bands were difficult to contour and regularly produced open or at least sharply emergent proximal contacts. Moreover, the material of choice for most direct posterior restorations was amalgam.
During the last few decades there has certainly been a dramatic reduction in the use of amalgam in all aspects of dentistry. Amalgam went from being used in 52.3% of fillings in 1998 to being used in only 7.1% of fillings in 2017.1 This reduction has been fueled in part by both ecological and ethical concerns related to the continued use of a restorative material that contains both elemental mercury and silver. In addition, there has been a major increase in local and state legislation mandating that amalgam reclamation efforts require water sediment filtration. Amalgam is still a legally permitted product, but it is becoming less and less favorable. This migration away from the use of amalgam has also ushered in the availability of a wider variety of posterior matrix systems designed to be used with composite materials. One such system is the DualForce™ Sectional Matrix System by Brasseler USA. This system is comprised of several innovative individual products that are distributed in a convenient starter kit.2
The DualForce Ultra-Wrap™ Matrix Bands are crafted from surgical grade stainless steel at a thickness of 0.015 in. They are uniquely sculpted and ultra-contoured to adapt to the interproximal area, and they are available in three different heights: 4.5 mm, 5.5 mm, and 6.5 mm. Furthermore, the design of these matrices includes an occlusal tab for ease of placement, and the custom pinch pliers enable a confident grasp. The intention is for the matrix band to be placed to fit gingivally below the floor of the proximal box and extend occlusally to just at or above the height of the approximating marginal ridge, and then the occlusal tab can be folded back across the adjacent tooth. This helps establish an ideal height in the new restoration. Although there are several other matrix systems on the market that utilize a pre-perforated area on the occlusal tab and the interproximal wing, I have found that the pre-perforated areas on these systems allow for a less secure control of the matrix band.
Regarding the system's wedges, the DualForce Active-Wedges™ are made of a high strength polymer resin that collapses as the point is introduced into the interproximal space. This leading point then rebounds to its original form once the wedge is fully seated. The middle part of the wedge initially contracts but then recovers to help seal the matrix/tooth margin interface. In addition, the notched handle provides grip support for placement as well as for retrieval using either cotton pliers or a curved hemostat. I have found it beneficial to use my left (ie, nondominant) index finger to help keep the band seated as I place the wedge. The DualForce Active-Wedges are provided in five sizes that are color coded for easy distinction. The black-colored wedges are the largest and possess a special "deep seal bubble" that is quite useful to help improve the cavosurface marginal seal on teeth with larger lesions and/or larger areas of proximal concavity along the root surface.
The hallmark of the DualForce Sectional Matrix System is its DualForce™ Rings, which are designed with dual nickel titanium tension wires that maximize separation force while seating the matrix band to the tooth to prevent composite flash. The kit contains two rings with color coded flexible molded pads: one green and one orange. The green-colored ring is intended for the molar area, and the orange-colored ring is intended for the premolar area or anywhere that additional separation force may be preferred clinically (Note the narrower space of the engagement area of the orange ring when compared with the green ring while the two rings are at rest in the image of the complete kit.) These rings help keep the contact pressure focused between the adjacent teeth in a revolutionary fashion. The interproximal contacts are molded by the rings, which create a seal around the matrix band and are very easy to set over the wedge and/or a rubber dam retainer.
There may be some disagreement among clinicians regarding which individual component is the most important part of the DualForce Sectional Matrix System, but I believe that most would readily agree that each of the elements in the kit play a pivotal role and synergistically result in a very exceptional and versatile matrix system that can help every practitioner elevate his or her Class II game.
1. University of Otago. Demise of dental amalgam outlined in new study. Medical Xpress website. https://medicalxpress.com/news/2020-02-demise-dental-amalgam-outlined.html. Published February 19, 2020. Accessed October 19, 2023.
2. DualForce™ Sectional Matrix System. Brasseler USA website. https://brasselerusadental.com/products/dualforce-sectional-matrix-system. Accessed October 19, 2023.
Donald B. Cork, DDS
Merritt Island, Florida
1. DualForce Rings are engineered with unique, dual nickel titanium wires that provide excellent balanced separation force on both mesial and distal surfaces.
2. The nickel titanium wires render the DualForce Rings resistant to fatigue so that they provide consistent separation force throughout their lifetimes.
3. DualFoce Rings do not sit flat but at an intentional 20° angle, which enables them to generate 5 pounds of separation force.
4. DualForce Active-Wedges possess ideal contour and strong internal spines that place significant force on the matrix band to seal all margins and prevent flash.