by Robert Ritter, DMD
When we consider the daily reality of adhesive cementation in most practices, it's easy to identify the most common restorations -- crowns, veneers, inlays/onlays, implants, and composites. When placing these restorations, there are a number of factors that dentists need to look out for. Obviously the restoration must fully seat; we should be able to easily clean up the residual cement; and we should feel confident that we have created a long-lasting bond to the tooth structure or underlying implant abutment.
In a modern practice, restorations such as thin or partial veneers, onlays or inlays, and crowns are made of a few popular materials. There are the standard porcelain-fused-to-metal (PFM) crowns, although use of PFMs has been continually decreasing due to metal costs. There is also full contour zirconium, which has been picking up speed as these materials improve and as PFMs lose popularity. Additionally, there is lithium disilicate and gold. Ultimately, when choosing and cementing a restorative material, the dentist's opportunity for long-term success hinges on his or her ability to fix patients' teeth with no problems. If we can achieve this, then we can help ensure profitability in private practice. With this in mind, dentists should review their cementation choices in light of their preferred restorative materials and techniques, with an eye toward selecting complementary and multifunctional materials that provide strength and versatility.
Today's cementation materials
Modern adhesive cements can be broken into two categories: resin-modified glass ionomers (RMGIs), and resin cements. RMGIs are used mainly for PFMs, gold, and all-zirconium restorations. With a clinical history of more than 10 years, we have seen good retention and very low postoperative sensitivity from these materials. They are also easily cleaned up, contributing to an overall ease of use.
Within the category of resin cements, there are three subcategories: self-adhesive resin cements, which have conditioner, primer and adhesive included; assisted self-adhesive resin cements, which require a separate self-etching resin before cementation; and adhesive resin cements, which require use of an etch-and-rinse adhesive before use.
When these adhesives are viewed respectively in the order noted above, we can see that their performance increases as the categories are read from left to right. So, too, does the cost for these materials. Therefore, using cements judiciously in the correct areas of the mouth and for the correct materials is not only a good way to limit the potential of failure or postoperative sensitivity, but also to control costs and avoid using an unnecessarily expensive material.
The good news is that since such a large majority of procedures in today's practices are focused in the posterior, dentists can concentrate their cementation inventories on the types of cement that are most useful for these cases -- RMGIs, self-adhesive, and assisted self-adhesive cements. Furthermore, when we consider the materials we are most likely to use in the posterior -- lithium disilicate, zirconia, or PFMs -- we see that the less costly self-adhesive and RMGI cements are well suited for these purposes. Ultimately, these materials can decrease stress and risk while helping ensure long-term results.
With our cementation priorities established, we can then move on to considering individual products within each category and how compatible these products are with our other preferred materials, including adhesives. For many dentists, it makes sense to consider staying within a brand family of cements across categories (e.g., 3M™ ESPE™ RelyX™ Luting Plus Cement for an RMGI, 3M™ ESPE™ RelyX™ Unicem 2 Automix Self-Adhesive Resin Cement for a self-adhesive, and 3M™ ESPE™ RelyX™ Ultimate Adhesive Resin Cement for an assisted self-adhesive). This not only simplifies inventory and ordering, but can also help the dental team quickly learn the necessary techniques and delivery systems for a given brand.
When choosing which brand family to concentrate on, dentists should consider factors including a manufacturer's track record in cementation, published data on the performance of each product, consistent quality, and customer service. If these aspects are made a priority, then chances are good that this family approach to cementation will help maximize efficiency and ultimately control costs. With this practical approach to cementation, dentists can concentrate on their goal of problem-free restorations that will serve patients for many years.
Robert Ritter, DMD, received his dental degree from the Medical University of South Carolina College of Dental Medicine and now runs a practice focused on adhesive and esthetic dentistry. He is a member of a number of respected dental associations including the American Academy of Esthetic Dentistry and the American Academy of Restorative Dentistry. Contact him at [email protected].
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