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Ask the Expert: An Interview with Matthew R. Miller, DDS on Sectional Matrix Systems

By Matthew R. Miller, DDS


There are many sectional matrix systems on the market today. Are some better than others? What should I be looking for when choosing a sectional matrix system?


Performing direct interproximal Class II restorations in restorative dentistry can sometimes be challenging and frustrating, especially as it relates to the intricacy of replicating the proper anatomy and contour. Selecting a matrix system that is easy to-use and one that provides a tight and anatomically correct contact is crucial. A system that is easy-to-use and requires minimal training helps ensure that a clinician and their team can use the system effectively and efficiently. Some matrix systems available on the market are compatible with the other dental instruments and equipment already commonly used in dental offices. This can help ensure that the clinician can integrate the system into their workflow easily. It is also important to choose a system that seals the gingival box and cavosurface margins interproximally. This allows for improved marginal adaptation, minimizes the likelihood for overhangs and excessive flash, and also decreases the risk for marginal gaps and recurrent decay.


What causes composite and adhesives to stick to the tines of the rings in some matrix systems? How can this be avoided?


Over time with use, adhesive and composite resin will often accumulate on the ring surface. This build up of resin is not only unsightly, it can cause issues with how well the ring will adapt to the interproximal surfaces of the teeth. If in the event resin adheres to a matrix ring while performing the restoration, it can create difficulties in removing the matrix ring from the restoration without damaging the restoration itself. This is because the composite resin can harden and bond to the matrix ring, making it challenging to separate the two. In some cases, the matrix ring may need to be cut or broken away from the restoration, which can result in damage to the restoration or the need for additional adjustments and contouring. With so many universal bonding agents containing multiple primers within their chemistry, this can cause the adhesive and resin to bond to the surface of the ring unintentionally.

One way to avoid this issue, is to use a matrix system that has a ring with a non-stick surface. The DualForce™ Rings (Clinicians Choice®) tines are coated with a non-stick plastic that prevents adhesive and resin from bonding to it, thus leaving the restoration intact and the ring free of debris accumulation. A design feature such as this can ensure a smoother and more efficient restoration process.

article image DualForce molar and pre-molar rings


Do some sectional matrix rings lose their ability to provide adequate separation force over time?


Dental sectional matrix rings can sometimes lose their tension over time, which can affect their performance during restorative procedures. This can be due to various factors such as material fatigue, improper handling, or frequent use. Using high-quality matrix systems such as the DualForce system, will provide consistent tension and accurate adaptation during restorative procedures. The DualForce Rings unique dual-spring technology ensures that the rings maintain their tension over time, even with frequent use. This can help reduce the need for constant adjustments and replacements, saving clinicians time and money.


What are the benefits of seating the ring at an angle vs. seating it flat on the tooth?


When rings sit flat against a tooth, it can prevent the ring from being positioned properly. This is especially true for rings that do not offer a wide clearance for access. This can result in a restoration that has an improper contour and poor interproximal contact. It can also prohibit the clinician from treating adjacent teeth at the same time. Improper ring placement can result in many issues including but not limited to: the ring popping off from an unstable placement, poor adaptation of the matrix such that the marginal seal and contour are now compromised, inadequate interproximal contacts, and difficulty placing the material leading to voids, overhangs, and other imperfections.

article image DualForce molar ring 20 degree angle

Some manufactures avoid this problem by creating a large ring circumference with an open access to the teeth in the area being treated. DualForce Rings sit at a 20º angle to allow for clearance away from the teeth cusps and rubber dam clamp as well as provide additional separating force between the teeth. By positioning the rings at this angle away from teeth and rubber dam clamps, it ensures that the ring is ideally seated. Therefore, the separating force in between the teeth is not compromised, nor is the contour of the restoration.


Sometimes it is difficult to get a tight seal at the base of the proximal box due to a concavity close to the furcation. How do you address this challenge?


Class II restorations can present several challenges, so when working on a pre-molar or molar with a concavity in the proximal box, the restorative process can become even more difficult. These contours and concavities are due to furcations within the tooth. If these areas are not properly sealed while performing a direct restoration, then marginal leakage and excess overhanging restorative material will result.

article image DualForce Deep Seal Active-Wedge
Dr. Matthew Miller headshot


Dr. Matthew R. Miller graduated with High Distinction from NYU College of Dentistry. He serves as a Key Opinion Leader in the dental industry and consults and lectures on endodontics, advanced restorative techniques, and digital and 3D imaging technology. Dr. Miller is a Clinical Ambassador and Advisory Board member for the Dental Advisor, working closely with companies to actively contribute to enhance the dental profession. Additionally, he is an Advisor for his local chapter of the Seattle Study Club. He maintains a private practice in Huntersville, NC.

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