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A New Resin Cement for “Conventional” Cementation
The self-adhesive resin cement offers simplicity and efficiency when seating high-strength, chairside CAD/CAM restorations.
Dentists seek simplicity, ease, and efficiency when it comes to seating high-strength restorations. Ivoclar Vivadent’s (http://www.ivoclarvivadent.us) new resin cement, SpeedCEM™, fulfills the need for quick “conventional” cementation of high-strength restorative materials. Examples of high-strength ceramics include feldspathic fused to zirconia (eg, Procera™, Nobel Biocare, http://www.nobelbiocare.com; Lava™, 3M ESPE, http://www.3mespe.com) and monolithic lithium disilicate (eg, IPS® e.max, Ivoclar Vivadent), which has been determined through mechanical mouth simulator testing by researchers in the ceramic testing group at New York University College of Dentistry to be among the strongest and most durable all-ceramic materials available.1
SpeedCEM is a dual-curing, self-adhesive resin cement applied directly through a double-push syringe, eliminating the need for additional mixing devices and applicators. Specifically designed for use when placing indirect restorations fabricated from metal, metal-ceramic (eg, porcelain-fused-to-metal [PFM]), high-strength ceramics (eg, zirconia, lithium-disilicate), and fiber-reinforced composites, SpeedCEM achieves shear bond values of 11 MPa to dentin and 17.8 MPa to enamel.2
Cementation of high-strength restorations typically requires a cement that is more radiopaque, to facilitate identification from recurrent caries, and completely self-cures when non-light-transmitting restorations are used.3 SpeedCEM demonstrates these characteristics and provides users with other advantages of this resin cement category, including easy clean-up, low technique sensitivity, and a simple, one-step procedure.3
In general, today’s self-adhesive resin cements already contain a self-etching primer within the cement, do not require etching or pre-treatment of the preparation, and may reduce or limit postoperative sensitivity.3 Available in three shades, SpeedCEM provides a faster and more efficient way to cement high-strength restorative materials by eliminating the need for dentists to condition the tooth preparation or apply dentin/enamel bonding agents.
Examples of self-adhesive resin cements include Maxcem (Kerr Dental, http://www.kerrdental.com), RelyX™ (3M ESPE), G-Cem™ (GC America, http://www.gcamerica.com), and SpeedCem. Overall, Speed CEM is an ideal cementation alternative for use when placing high-strength all-ceramic posterior restorations, as in the case of the treatment provided to a 55-year-old woman who presented with a failing amalgam core on tooth No. 20 that had been completed 7 years earlier (Figure 1). Recurrent caries developed around the amalgam core, but fortunately the tooth and restoration had not fractured during this time.
The recommended treatment was a full-coverage restoration using the existing titanium post, because its removal could potentially fracture the delicate surrounding tooth. Additionally, the patient’s requirements for a natural-looking restoration and one-visit dentistry also were incorporated into the treatment plan. Therefore, although full-coverage options include PFM or zirconia, gold, and all-ceramic restorations, the patient selected the all-ceramic IPS e.max CAD lithium-disilicate option based on the material’s esthetic properties and one-visit completion.
Preparing for Chairside CAD/CAM Crowns
Under isolation, the amalgam restoration and recurrent caries were removed. The endodontic post was salvaged and demonstrated complete stability. The core was rebuilt using an esthetic composite (IPS® Empress Direct, Ivoclar Vivadent) bonded to the tooth structure using a single-component bonding agent (ExcITE®, Ivoclar Vivadent). The composite was mechanically locked into the undercuts and internal features of the titanium post (Figure 2).
Two millimeters of occlusal reduction was performed, and a conservative supragingival chamfer margin was created (Figure 3). The preparation was imaged into a CEREC computer (Sirona Dental Systems, http://www.sirona.com), and the full-coverage restoration was designed.
After milling, the “blue crown,” in its lithium-metasilicate stage, was tried in (Figure 4 and Figure 5). No adjustments to the interproximal contacts or occlusion were necessary. A subtle light brown stain (IPS e.max CERAM Shade 2) was applied to the gingival third and occlusal surface, after which a spray glaze was applied (IPS e.max CAD Spray Glaze) and the crown was fired in a dual-ramp cycle in the chairside furnace for 20 minutes. The final transformation of the lithium-metasilicate crystals to form lithium-disilicate crystals—as well as the vanadium ionic change within the glass component to change the color from blue to a yellow—occurred during the firing.
Seating IPS e.max CAD Using SpeedCEM
The restoration was tried in to confirm fit. Then, the restoration’s intaglio surface was etched with a hydrofluoric acid for 20 seconds (IPS® Ceramic Etch, Ivoclar Vivadent), rinsed, and dried, after which silane was applied (Monobond-S, Ivoclar Vivadent). Because the preparation was conservative, the decision was made to bond the restoration to the tooth using a self-etching resin cement (SpeedCEM) in a transparent shade.
The cement was placed within the crown, and the crown was seated onto the cleaned tooth surface (ie, cotton pellet and isopropyl alcohol) (Figure 6 and Figure 7). Roughly 90 seconds later, the cement reached a gel phase and was easily cleaned up using an explorer tip. Careful flossing removed the interproximal cement.
The cement and restoration were given a final light-cure for 5 seconds from each surface using an LED curing light (Figure 8 and Figure 9). A postoperative radiograph was taken to confirm that the excess cement had been completely removed.
SpeedCEM, in combination with highstrength all-ceramic restorations, enables predictable, definitive cementation following a user-friendly technique. The protocol outlined here is straightforward, and the clean-up of excess cement lends to efficiency during the seating appointment.
The author has received honoraria from Ivoclar Vivadent and Sirona Dental Systems.
1. Guess PC, Zavanelli R, Silva NR, Thompson VP. Clinically relevant testing of dental porcelains for fatigue and durability with an innovative mouth motion simulator. Presented at: 39th Annual Session of the American Academy of Fixed Prosthodontics, February 2009, Chicago, IL.
2. Data on file. Ivoclar Vivadent. SpeedCem Scientific Document.
3. Christensen GJ, Child PL. Self-adhesive resin cements-a replacement or an alternative? Clinicians Report. November 2009;2(1):1-4.
About the Author
Todd Ehrlich, DDS