Class II Posterior Composite: Reproducing the Durability
Palodent® Plus Sectional Ring and Matrix Products Modernize the Procedure
Todd Snyder, DDS
One of the most common dental office procedures is the posterior bonded tooth-colored composite resin. This frequent restorative technique is extremely complicated because of all the steps that go into the proper utilization and placement of restorative materials. It becomes even more complicated when the cavity extends interproximally—the preparation design often requires the use of a matrix system to recreate the interproximal surface against the adjacent tooth and contain the restorative material during placement until it becomes solidified. Some practitioners do not feel confident in their ability to consistently create good interproximal contacts from modern tooth-colored direct restorations. To address this, different types of devices, tools, and materials have been created to help dentists achieve the ideal interproximal contact when using composite resin and glass ionomer restorative materials.
Some practitioners have not yet embraced the modern tools that can alleviate their concerns over a good contact and contour being achieved consistently. Rather than implementing newer devices, these practitioners try to accomplish the arduous task with traditional Tofflemire matrix band systems or variations. Although any system can work, depending on the type of preparation design and situation that is presented to the practitioner, a more consistent approach may be available. Traditional Tofflemire matrix systems are still necessary for the occasional mesial or distal surface of a tooth when no adjacent tooth is present or for the placement of large core buildups that do not necessitate a contact because an indirect restoration is being placed. However, a tighter interproximal contact may be achieved by implementing a modern restorative sectional ring and matrix device, such as the Palodent® Plus sectional matrix system (Dentsply Sirona, palodentplus.com).
Tofflemire bands have difficulty mimicking the true anatomical shape and contour of a tooth when modern tooth-colored direct restorative materials are used. Using a Tofflemire system with composite will typically result in a very flat profile from the gingival margin to the occlusal-proximal cavosurface (Figure 1).
When using a curved or dead-soft Tofflemire band, a slightly better anatomical shape can be achieved than with traditional Tofflemire bands; however, the contact will typically not be tight enough because of a lack of tooth displacement. Control of the placement and tightness of the contact against the adjacent tooth is difficult, and simple wedging does not provide enough displacement of teeth to offer consistent results. Additionally, the contact point when using the Tofflemire band is typically at the occlusal surface; any adjustments made to occlusion may strip away the small light contact, which creates an open contact (Figure 2).
When compared to Tofflemire systems, the Palodent Plus sectional matrix system offers many distinct advantages. The Palodent Plus ring is made of a NiTi metal wire with two glass-fiber reinforced plastic feet, often referred to as tines. This ring offers outstanding spring strength and memory, delivering a flatter force curve that offers optimum force across a wide range of posterior embrasures. The metal has a substantially longer lifespan, with a more consistent tooth displacement for reliable tight contacts. The glass-fiber reinforced plastic tines are V-shaped to hold the wedge precisely between the teeth, in contrast to traditional ring systems that necessitate the small tines being placed on only one side of the wedge or occasionally on top of the wedge.
The wedges that are used with the Palodent Plus system have been modified to follow the root contour, as well as the gum and bone contours. The wedge holds the matrix firmly in place against the gingival margin while causing the least amount of damage to the surrounding tissue. The Palodent Plus matrix is held firmly against the gingival floor of the preparation to achieve a good seal so that excess material is not extruded, which would require additional cleanup to remove flash. And unlike previous sectional ring systems, the Palodent Plus ring does not interfere with or displace the wedge.
The Palodent Plus system contains a universal ring (Figure 3) and a narrow ring (Figure 4). The tines of the narrow ring are closer together and exert up to 4 kg of separating force, which is ideal for premolars. The system has multiple matrix sizes, ranging from 3.5 mm to 7.5 mm, and the 6.5 mm and 7.5 mm sizes feature subgingival tabs to handle deep restorations. To simplify the process of placing the wedges and matrices, pin tweezers are included with the system. These unique tweezers use the various holes on the wedge guards, wedges, and matrices to hold them tightly for easy placement and removal.
The Palodent Plus EZ Coat matrices are thin metal bands featuring a non-stick coating, greater curvature, and a very pronounced marginal ridge—all of which help to create the desired anatomy and proper contour when implemented (Figure 5 through Figure 7). The precontoured shape allows for the creation of ideal facial-to-lingual convexity, like natural teeth. Additionally, the contour of the matrix from the gingival margin to the occlusal surface is optimally created to position the interproximal contact in the middle to incisal third of the adjacent tooth. The contour that is created mimics the appearance of a natural tooth with ideal contact positions. The occlusal, gingival, buccal, and lingual embrasure spaces are all easily fabricated, often with minimal to no flash.
The interproximal composite restoration can be a difficult procedure to perform correctly, but with the right tools, it can be done consistently and more easily. Oftentimes, dentists still implement traditional tools and techniques, which may work, but when compared with modern tools, can make a difficult procedure even more demanding and time-consuming. The Palodent Plus sectional matrix system offers a level of reproducibility that has been lacking in many other systems and can help dentists routinely create a good anatomical restoration with excellent contacts.
About the Author
Todd Snyder, DDS
Laguna Niguel, California
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