Compared to a slick, new chairside computer-aided design/computer-sided manufacturing (CAD/CAM) setup, dental matrix systems may seem pretty mundane. But truth be told, they really are the bread and butter of restorative dentistry.
Good matrix systems provide a multitude of benefits. They separate one tooth from another, and contain composite material during the restorative process. By creating a wall on the surface of a tooth where none exists, matrix systems help to form proper interproximal contacts, help shape restorations, and keep flash at bay — which not only saves clinicians cleanup time, but also saves patients from the potential for subgingival irritation.
Dental Matrix System Options
The most prevalent kind of matrix system for years was the Tofflemire, consisting of a retainer, used to secure metal bands circumferentially around the tooth. Developed in the 1940s, this arrangement works best for amalgam restorations, especially Class IIs, as that material is condensable. 1Owens BM, Phebus JG. An evidence-based review of dental matrix systems. Gen Dent. 2016;64:64–70.
But while the Tofflemire system is still widely used, especially for large, multisurface posterior restorations, newer sectional systems have gained traction in recent years. That’s primarily because composite materials are not condensable, meaning they can’t be pushed against the flat band to create an outer contour. 2Stone R. Piece of cake. Mentor. 2017;8(7):32–36.
Sectional matrix systems provide a sort of mold for composite material. Sectional bands come in a range of sizes. Some even feature nonstick coatings for easy removal. They allow clinicians to create anatomically correct contours with composite — a patient pleaser for sure.
Rings are used to hold sectional matrices in place. Some feature V-shaped, silicone tines, soft enough to hug anatomy, while distributing enough equal force on tooth surfaces to contain material and separate teeth. This fosters tight interproximal contacts because once the ring is removed, the adjacent tooth that was nudged out of the way will resume its original position against the newly restored tooth. 3Owens BM, Phebus JG. An evidence-based review of dental matrix systems. Gen Dent. 2016;64:64–70. 4Stone R. Piece of cake. Mentor. 2017;8(7):32–36.
Commonly made of nickel titanium, rings may be stackable, for work on large MOD restorations or simultaneous multiple restorations. Some even feature clear tines to facilitate light curing. 5Owens BM, Phebus JG. An evidence-based review of dental matrix systems. Gen Dent. 2016;64:64–70. 6Stone R. Piece of cake. Mentor. 2017;8(7):32–36.
Wedges are used with matrix systems to help brace bands so that composite material doesn’t ooze out at the gingival margin. But while wooden wedges are used with Tofflemire systems, sectional systems utilize wedges that offer enough flexibility and curvature to conform to tooth contours, creating a better seal.
Other innovations include directional fins to help lock the wedge in place, transparent wedges to facilitate light curing, and wedges that compress during placement but flare once in place to enhance seal. There are even wedges that are fitted with small shields to protect neighboring teeth during preparation. 7Stone R. Piece of cake. Mentor. 2017;8(7):32–36.
Of course, sectional systems are mainly intended for posterior restorations. Anterior teeth do not have occlusal surfaces or proximal boxes, but rather incisal edges. Anterior matrices often include retainerless materials, such as tapes, that are transparent to facilitate light curing. Some are preformed and some are tinted blue to contrast matrix from tooth structure without interfering with polymerization. 8Stone R. Piece of cake. Mentor. 2017;8(7):32–36.
Dental Matrix Systems and Isolation
While good matrix systems are invaluable, for composite restorations, they would be useless without a good isolation system. Although any dental dam would do, it’s hard to argue that comprehensive systems such as Isolite 3 wouldn’t give clinicians an even better chance of creating beautiful restorations — while enhancing patient comfort and safety.
Courtesy of a lightweight, flexible, transparent mouthpiece, the Isolite 3 system gives clinicians the unobscured field they need for the best outcomes. Add in illumination via traditional white light or a new cure-safe amber light, and constant evacuation of fluids, which could otherwise compromise hydrophobic restorative materials, and you’ve got a winning ticket to restorative success.