Inside Dental Assisting
Use of a Self-Adhesive Resin Cement with Convenient Automix Delivery
Shea Nelson, LDA
The success of a cementation procedure is vital to the long-term success of a restoration. With a proper cement product and procedure, a durable bond will be created and the margin between the tooth and the restoration will be both esthetic and strong, bolstering the strength of the entire tooth. However, if the cement is not mixed or applied correctly, the life of the restoration can be dramatically shortened.
The cementation process can be simplified in many cases with use of a self-adhesive resin cement. Unlike typical adhesive resin cement, which requires etching, priming, and bonding, as well as being highly technique sensitive, a self-adhesive resin cement can be applied quickly and in minimal steps, and also offers a higher moisture tolerance. The first self-adhesive universal resin cement, 3M™ ESPE™ RelyX™ Unicem Self-Adhesive Resin Cement (3M ESPE, http://solutions.3m.com), was introduced in 2002, and clinical support for the material has been consistently positive, making it the world's most proven resin cement. A 7-year evaluation of more than 1,450 all-ceramic and PFM restorations cemented with the product found a debonding rate of just 2.4%. Additionally, postoperative sensitivity was reported by only 1.1% of patients in the group.1 Other long-term studies have found similarly positive results in stability and minimization of sensitivity.2-4
Now, the next generation of this product has been introduced as RelyX™ Unicem 2 Automix Self-Adhesive Resin Cement. While the material's formulation has undergone subtle improvements, the most dramatic change for assistants is the convenient new automix delivery system. The product comes in an easy-to-use syringe that dispenses the cement in an already mixed state, eliminating the need for a separate mixing step. Three different types of mixing tips also offer options depending on the indication. Regular mixing tips are designed for standard applications, while endo tips are available to help ensure a void-free application when working in the root canal. Finally, for inlay and onlay procedures, special intraoral tips are designed to extrude the product exactly where it is needed. The syringe applicator is smaller and easier to handle than the previous generation, making it easy to maneuver in the mouth.
Beyond the new delivery system, modifications made to the new generation include the addition of a new monomer and a new rheology modifier. Processing of the material's filler particles has also been optimized. These new modifications result in increased bond strengths, even better mechanical properties, and improved esthetics.
For assistants, the automix delivery system adds new convenience to the use of a self-adhesive resin cement. Less clean-up is necessary, and the new design also allows the dentist to dispense only the amount of material that is needed. The new designs for the mixing tips are also a convenient change. In addition to their functionality in clinical situations, they are also packaged clearly, making them easy to identify quickly.
Studies are underway to provide additional clinical support for the new generation, but early results have been positive. A baseline evaluation for one study found no cement-induced hypersensitivities at 1 week, and no detectable marginal gaps.5
While dentists and assistants are likely already accustomed to the reliability of the original RelyX™ Unicem cement, this generation's new delivery system and enhancements to bond strength, mechanical properties, and esthetics help to deliver an even higher level of performance. Together, these modifications create a formula that is designed to function well with the new syringe delivery and offer the overall performance that dentists have come to expect from RelyX™ Unicem cement. The simple handling and clean-up made possible with the automix syringe makes it simple for assistants to use with confidence. (Figure 1 and Figure 2)
1. 3M ESPE RelyX™ Unicem Self-Adhesive Universal Resin Cement 7-Year Clinical Performance. The Dental Advisor. 2010;27(4).
2. Behr M, Rosentritt M, Wimmer J, et al. Self-adhesive resin cement versus zinc phosphate luting material: A prospective clinical trial begun. Dent Mater. 2009;25(5):601-604.
3. Geraldeli S, Stanford C, Dawson D, et al. Single and Multi-Step Luting Agents after Four Years. IADR. 2009; Miami, FL. Abstract #1639.
4. Peumans M, De Munck J, Van Landuyt K, et al. Clinical evaluation of a self-adhesive luting agent for ceramic inlays. J Adhes Dent. 2009.
5. Syrek A, Reich G, Ranftl D, et al. Evaluation of the clinical performance of Lava™ DVS crowns luted with self-adhesive resin cement. Baseline Report, 3M ESPE AG.
About the Author
Shea Nelson, LDA
St. Paul, Minnesota