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Using a Nano-Hybrid Composite for Esthetic Posterior Restorations
Christopher D. Ramsey, DMD
The esthetic value is important, but should not be the only concern.
For several years, the IPS Empress® (Ivoclar Vivadent, http://www.ivoclarvivadent.us) all-ceramic brand has been known for its high level of esthetics when mimicking the characteristics of natural teeth. Since its debut more than 15 years ago, over 37 million indirect restorations—both crowns and veneers—have been fabricated with the IPS Empress pressed-ceramic system.1
The most recent addition to the IPS Empress family of products is IPS Empress Direct, a light-curing, nanohybrid direct composite that demonstrates exceptional handling properties for achieving consistent anterior esthetics similar to ceramics, but with the on-demand ease of composite. IPS Empress Direct features a broad range of true-to-nature dentin and enamel shades, as well as different translucencies and opacities, to create infinite opportunities for realizing esthetic results for every indication—including posterior restorations. Traditionally, it has been virtually impossible to restore the original optical properties of natural teeth using just one shade of composite, because dentin is more opaque than enamel. The IPS Empress Direct dentin and enamel shades feature calibrated translucencies that work together, creating exceptional esthetics with an accurate color match every time. As a result, dentists can easily mimic the optical effects of natural tooth structures in a way similar to ceramic, but with the simplicity of direct composite.
In particular, the dentin shades feature a more opacious (7.4% to 7.9%), saturated chroma that generates the basic color of the tooth from within.2 The translucency of the enamel shades has been adjusted to provide a natural depth to the restoration, diffusing the color of the dentin in a manner similar to natural tooth structure. Further gradations in translucency can be achieved using the translucent and opalescent shades.
IPS Empress Direct demonstrates a high radiopacity compared to natural tooth structure, thereby ensuring clear visibility on radiographs for enhanced diagnosis. The composite is considerably less sensitive to light than other materials, providing ample working time for sculpting the anatomy of restorations. Because IPS Empress Direct is a nanohybrid composite, it retains its gloss similar to a microfill or nanofill, but since it is a hybrid, it also demonstrates a higher strength and modulus of elasticity, making it appropriate for posterior indications.3 IPS Empress Direct also exhibits quick and easy polishing characteristics as a result of its even distribution of filler particles.
When confronted with such a restoration, the esthetic value is important, but should not be the only concern. With restorations, such as in the case presented, clinicians should be able to provide a restoration that demonstrates no postoperative sensitivity. Typical ways of preventing sensitivity, such as the use of a rubber dam, are not used nearly as often as they should be. Typically, only around 5% of dentists use dams when doing a restoration procedure. It is important that all clinicians use rubber dams to provide isolation of the preparation.
Once the preparation is isolated, the most important and often overlooked step is the use of glass ionomers. These products are typically light- or self-curing and demonstrate high translucency, along with high radiopacity. Glass ionomers can be used in a variety of applications, such as restorations composed of metal, metal-ceramic, and metal (with resin) veneers. Glass ionomers also prove to be a useful tool in high-strength, all-ceramic restorations.
Among their many uses, glass ionomers cover not only the dentin and possible discoloring, but also provide a 99% reduction in postoperative sensitivity.4These features are useful in dealing with caries that present with gray coloring. The coloring will not present through the restoration when using glass ionomers as they would if the material was left unused. Glass ionomers also completely seal the dentin, preventing any postoperative concerns dealing with sealing and sensitivity.
After sealing the dentin with a glass ionomer, it is critical to use a desensitizing agent such as Gluma® (Heraeus Kulzer, http://www.heraeus-kulzer-us.com) as well. By applying such an agent, the possibility of postoperative sensitivity is reduced. This allows for an esthetically pleasing and functional restoration. With its use, the patient will not experience the pain or sensitivity typically felt after these types of restorations.
It is also important to note some other factors that play a role in providing the best of restorations, with minimal discomfort. If clinicians do not take the time to ensure that a restoration is done completely, it increases the chances of sensitivity and postoperative discomfort. One of these steps, etching, should not be left uncompleted. It is important to take a full 15 to 20 seconds to ensure a proper etch. This is not to be overlooked. The placement of adhesives is also extremely important, as it is the linking step of the entire process. By rushing this step, the link is not fully complete and the restoration will not be as successful as it could be.
The success of all restorations lies in the use of an array of tools and products that provide esthetically pleasing results and full functionality without discomfort to the patient. That being said, the clinical protocol must involve these steps, with the necessary time allotment, to provide an esthetically pleasing, functional, and desensitized restoration.
The placement technique for IPS Empress Direct is predictable and simple. The steps involved are demonstrated here in the case of a 36-year-old woman who presented with caries in a posterior tooth (Figure 1).
The caries were removed from the tooth, and the tooth was prepared (Figure 2). To ensure complete isolation, a rubber dam was placed. In addition, a Triodent V3™ ring (http://www.triodent.com) was used to facilitate proper development of contacts and contours (Figure 3).
Next, a desensitizing agent (Gluma) was applied to the preparation (Figure 4). An etchant gel was then applied to the preparation for 15 seconds, after which the preparation was rinsed and dried (Figure 5).
A fifth-generation adhesive bonding agent (ExciTE F, Ivoclar Vivadent) was applied to the preparation for 10 seconds (Figure 6). The bonding agent was air-thinned with high pressure, then light-cured for 10 seconds using an LED curing light. After light-curing, the IPS Empress Direct composite in shade B1 enamel was placed, sculpted, and cured for 40 seconds each from the occlusal, buccal, and lingual aspects (Figure 7 and Figure 8). The rubber dam and ring were removed, and the restoration was finished and polished using a series of integrated polishers (Figure 9 and Figure 10).
The IPS Empress system has evolved significantly over the years in response to the various demands of dental professionals. The newest addition is IPS Empress Direct, a light-curing, nanohybrid composite with outstanding handling properties that enable dentists to achieve anterior esthetics similar to ceramics, but with the on-demand ease of composite. Its wide variety of true-to-nature dentin and enamel shades, as well as different levels of translucencies and opacities, provides limitless opportunities for realizing esthetic results. Because IPS Empress Direct is a nanohybrid composite, it provides the benefit of a higher strength and modulus of elasticity, making it suitable for posterior indications (Figure 11).
1. Ivoclar Vivadent USA. IPS Empress system dentist: a time-tested system offers new possibilities. 2010. Available at: http://ivoclarvivadent.com/content/products/detail.aspx?id=prd_t1_700517700&product=IPS+Empress+System+dentist
2. Illie N, Hickel R. Investigations on mechanical behaviour of dental composites. Clin Oral Investig. 2009:13(4):485-487.
3. Hardan LS, Amm EW, Ghayad A, et al. Effect of different modes of light curing and resin composites on microleakage of class ii restorations—part II. Odontostomatol Trop. 2009;32(126): 29-37.
4. Rusin RP, Agee K, Suchko M, Pashley DH. Effect of a new desensitizing material on human dentin permeability. Dent Mater. 2010; 26(6):600-607.
About the Author
Christopher D. Ramsey, DMD