RMGI Liners—Are You Missing an Opportunity?
Better empirical results for restorative procedures
Many dentists almost never use a resin-modified glass ionomer (RMGI) liner, believing that they can achieve the same benefits by utilizing good technique and restorative materials. If you are one of those dentists who rarely or never takes advantage of RMGI materials, you may want to reexamine their capabilities. Postoperative sensitivity is one of the most common concerns of dentists in cases involving deep restorations, and sealing the dentin with an RMGI liner can be an effective way to prevent this issue. In addition, these liners also protect against postoperative sensitivity by acting as a thermal barrier, preventing microleakage, and providing stress relief. These materials also bond in a moist environment and do not remove the smear layer.
Although some studies have found mixed results with the use of RMGI liners to prevent postoperative sensitivity, it’s important to remember that sensitivity is subjective, and can be caused by a number of factors. Sensitivity with a large restoration can be caused by variables such as poor occlusion, nerve involvement, the injection site, or simply the patient’s perception of pain. I personally feel much more confident when using an RMGI liner like 3M™ ESPE™ Vitrebond™ Plus Light Cure Glass Ionomer Liner/Base, knowing that this material will have good adhesion to dentin and will seal off the fluid in the dentinal tubules that could cause hypersensitivity.
I also sometimes utilize a total-etch adhesive surrounding the liner. I’ve heard clinicians argue that using a total-etch system alone is sufficient, but we must also consider that in deep excavations it can be difficult to achieve an ideal bond using only total-etch adhesives, due to the increased dentinal fluid.
After 25 years in practice, I have seen better empirical results using a liner versus not using one. In addition to the liner’s benefits in reducing sensitivity, an RMGI also gives the clinician the added assurance of fluoride release. The combination of an RMGI and a composite restorative to which it can bond may also help contribute to greater longevity for the restoration.
As an alternative to placing a liner, some dentists choose to use a flowable composite, citing greater ease of use as the rationale. The flowable’s fluid consistency and the ability to directly inject it into the preparation contribute to this ease of use. However, clinicians who consider this technique should weigh it carefully against the added benefits of using a RMGI liner. Not only does an RMGI liner offer fluoride release, but it also forms a better seal to dentin than a flowable. Furthermore, delivery systems for RMGI liners have evolved and made these products simpler to use. Vitrebond Plus liner/base, for example, comes in the 3M™ ESPE™ Clicker™ Dispenser, which consistently dispenses the proper ratio of paste-liquid formula.
Ultimately, clinicians should take a hard look at both their materials and the clinical situation to determine the best treatment plan. There are many good RMGI materials available, and with proper use and sound clinical judgment, dentists can take advantage of them to place long-lasting, comfortable restorations.
About the Author
Ronald Perry, DMD, is the director of the Gavel Center for Restorative Research and clinical professor at Tufts University School of Dental Medicine and restorative dentist in Weymouth, Massachusetts.
Adheres well to dentin
Seals off fluid in dentinal tubules that could cause hypersensitivity
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