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Using the Selective Etch Technique for Esthetic Restorations
A combination of products can help dentists achieve desirable results.
By Robert Ritter, DMD
In many direct procedures, dentists aim to provide restorations with esthetic appeal, staying power, and maximum service to the patient. A combination of products that can help dentists achieve this result is especially valuable. 3M ESPE (www.3MESPE.com) recently introduced a next-generation composite, 3M™ ESPE™ Filtek™ Supreme Ultra Universal Restorative, that helps dentists easily deliver results that meet patients’ esthetic needs. Combined with a clever adhesive technique and 3M ESPE Adper™ Easy Bond Self-Etch Adhesive, the restorative can create long-lasting, natural-looking results with high bond strengths.
The new Filtek Supreme Ultra Universal Restorative follows the well-regarded Filtek™ Supreme Plus Universal Restorative, which according to the manufacturer, was a true nanotechnology that exhibited wear-resistance similar to enamel.1 The new generation offers these same benefits with the addition of improved handling of translucent shades, excellent polishability and polish retention, an expanded selection of body shades, and improved fluorescence.
To give any composite restoration a proper foundation, however, an excellent adhesive technique is necessary. The proper adhesive selection is especially important when working on surfaces that involve both dentin and enamel. In these cases many dentists choose a selective or preferential etch technique, in which a phosphoric acid is applied only to the enamel area and a self-etch adhesive is used. This allows a deep acid etch on the enamel margins while maintaining the benefits of a self-etch product, including low postoperative sensitivity and moisture tolerance on dentin. Furthermore, this technique can help create restorations that blend more naturally at the margins.
A concern when using the selective etch procedure, however, is that with some adhesive systems, bond strength can be compromised if etchant inadvertently reaches the dentin.2,3 Adper Easy Bond Self-Etch Adhesive, however, is formulated with chemistry similar to a total-etch adhesive, Adper™ Single Bond Plus Adhesive, meaning that the bond strength to dentin is not adversely affected if etched.4 With this technique, the bond strength to cut and uncut enamel is equivalent to that achieved by using a fifth-generation total-etch bonding agent.5
The following case demonstrates how Filtek Supreme Ultra Universal Restorative and Adper Easy Bond Self-Etch Adhesive can be used with a selective etch technique.
The patient, a 25-year-old man, presented with discomfort on the lower left side of his mouth. An examination revealed decay on the occlusal of tooth No. 19 (Figure 1 ). The decay extended relatively deep on the distal occlusal surface of the tooth. It was determined that a composite restoration would be placed to provide an esthetic solution.
Prior to preparation of the tooth, the patient was instructed to bite down on a thermoplastic wafer in order to capture the occlusal anatomy. The wafer was set aside and the area was isolated. While excavating the preparation, it was determined that the decay extended very close to the pulp (Figure 2 ). The cavity was rinsed and dried, and 3M ESPE Vitrebond™ Plus Light Cure Glass Ionomer Liner/Base was applied in a thin layer to the dentin surface, with attention paid to avoid the margins, then cured for 20 seconds (Figure 3).
A phosphoric acid was applied to the enamel periphery of the preparation in order to create a strong etch pattern (Figure 4). The etchant was left for 10 seconds, then rinsed. Adper Easy Bond Self-Etch Adhesive was then applied for 20 seconds to all surfaces of the cavity (Figure 5 ). The adhesive was then air-thinned for 5 seconds, followed by a 10-second light cure (Figure 6).
Filtek Supreme Ultra Universal Restorative in dentin shade A2 was applied and light-cured for 40 seconds (Figure 7). A second layer of restorative in enamel shade A1 was then applied (Figure 8). Prior to curing the enamel layer, the thermoplastic wafer was fit back into place on the tooth and pressed down to mold the shape of the occlusal surface (Figure 9). A curing light was then used to cure the composite through the wafer material. The wafer was removed, and final finishing and polishing steps were completed (Figure 10).
The motivation behind performing the selective etch procedure is increasing bond strength to cut and uncut enamel. Typically, self-etch adhesives do not perform as well on uncut enamel, and sixth- and seventh-generation products do not readily lend themselves to use in conjunction with phosphoric acid. However, this is not the case with Adper Easy Bond Self-Etch Adhesive, which has the flexibility to be used both with and without phosphoric acid. The product has proven to be a relatively simple system to use, and the incidence of postoperative sensitivity has been negligible.
In this specific case, the patient had a healthy periphery of enamel despite the deep decay into dentin. In order to maximize the ability to bond to the surface enamel, while at the same time reduce the potential for postoperative sensitivity in the very deep affected dentin, the combination of Vitrebond Plus Light Cure Glass Ionomer Liner/Base and Adper Easy Bond Self-Etch Adhesive was used.
The final result was one that can be expected to serve the patient well for some time, with a strong bond and minimal sensitivity. In addition, the use of Filtek Supreme Ultra Universal Restorative allows the restoration to withstand wear and maintain optimum esthetics during its service.
The author is a current consultant for 3M ESPE.
1. Katholic University Leuven. In vivo clinical study. Data on file, 3M ESPE.
2. Van Landuyt K, Kanumilli P, De Munck J, et al. Bond strength of a mild self-etch adhesive with and without prior acid-etching. J Dent. 2006;34(1):77-85.
3. Ikeda M, Tsubota K, Takamizawa T, et al. Bonding durability of single-step adhesives to previously acid-etched dentin. Oper Dent. 2008;33(6):702-709.
4. Taschner M, Breschi L. Microtensile Dentin Adhesion of All-in-One Systems to Etched Dentin. IADR, Barcelona, Spain, 2010.
5. Thalacker C, Richter I, Kappler O, Rumphorst A. Bond Strengths of All-in-one Adhesives with and without Acid Etch. CED/IADR, Munich, Germany, 2009.