September 2012, Volume 8, Issue 9
Published by AEGIS Communications
Tetric EvoCeram: Not Just for Small Restorations
Light-curing, universal nanohybrid composite offers strength, durability, predictability, esthetics, and ability to conserve tooth structure.
Being able to identify defective restorations and/or carious lesions needing treatment is obvious and universal for most dentists. However, dentists may differ in their treatment planning depending on factors such as cost and convenience for the patient, as well as clinical conditions and the clinician’s choice of material. In a field that is always evolving with new products on the market, the selection of material must be one that meets the clinician’s needs as well as the patient’s, while satisfying a predictable esthetic outcome and prognosis. Decisions on whether to use direct composite or ceramic restorations can often be pragmatic and based on the clinician’s familiarity with a product or procedure.
Research studies have shown that excessive cutting of sound tooth structure during tooth preparation weakens the tooth. This weakening is initiated by in increase in tooth flexure and an isthmus width greater than one third the intercuspal distance, which reduces the load required to fracture the tooth by 50%. When faced with these structural compromises, the restorative dentist may choose porcelain for strength and to reduce the risk of tooth fracture. This is a viable option, but to be considered is the amount of tooth structure that must be removed to meet the requirements of the ceramic restorative material. On the other hand, dental composite in and of itself is an extremely predictable and durable material. Technique and the ability to manage factors such as occlusion have more bearing on the long-term result than anything else. Tetric EvoCeram® (Ivoclar Vivadent Inc., www.ivoclarvivadent.com) is a light-curing, universal nanohybrid composite that offers a variety of benefits. Proven clinical studies involving anterior and posterior restorations demonstrate that Tetric EvoCeram has the longevity and durability required of direct composites. With a polymerization on demand (POD) system, Tetric EvoCeram eliminates the risk of premature polymerization, using a special additive within the photoinitiator system. It also offers smooth handling, adaptability, and low polymerization shrinkage rates to reduce the risk of marginal leakage and secondary caries. The refractive indices of the monomers, fillers, and nano-color pigments of Tetric EvoCeram produce a chameleon effect, allowing restorations to naturally blend with excellent esthetics.
A 31-year-old patient needed old composite and amalgam restoration replacement on teeth Nos. 31 and 32, respectively (Figure 1). Tooth No. 31 had existing occlusal and buccal composites that were minimal to moderate in both broadness and depth. The selection of direct composite as the material of choice was obvious and predictable to restore with excellent prognosis. Tooth No. 32 had an amalgam that was deep and extended more than three quarters the intercuspal distance. While porcelain could certainly be used, it would require some additional tooth preparation. The choice to use direct composite was made to deliver an esthetically pleasing restoration with good prognosis while conserving as much existing tooth structure as possible.
Before starting the restorative work, the shade was determined by placing a small ball of Tetric EvoCeram onto the teeth, which was then lightly manipulated and light-cured. Even though a comprehensive occlusal examination was completed at the initial visit, a quick check of the occlusion on the teeth was performed in consideration of the anatomical design of the restorations. The patient was anesthetized with 2% lidocaine block, and a non-latex rubber dam was placed with an 8a clamp to ensure proper isolation (Figure 2). Tooth preparation was completed using a #330 bur (SS White Burs, Inc., www.sswhiteburs.com) with an electric handpiece. Because ceramic was not the material selected in this case, the tooth preparation design was only what was required to remove the existing restoration and any recurrent decay. Sharp line angles were lightly softened with the same bur at an angle (Figure 3).
Once tooth preparation was complete, a 35% phosphoric acid-etch was placed and agitated for 15 seconds, then rinsed and lightly air-dried (Figure 4). A fifth-generation bonding agent was used, agitated, and allowed to sit for 10 seconds before drying with a thin stream of air to remove excess material. The bonding agent was then light-cured for 10 seconds. A flowable composite was placed in a thin layer and manipulated with a dental explorer to ensure adaptation into small crevices and light-cured for 20 seconds (Figure 5). Tetric EvoCeram Shade A1 was placed in increments of 2 mm and adapted to the cavity walls with a posterior gold composite instrument and then light-cured for 10 seconds per the manufacturer’s instructions (Figure 6). Tetric EvoCeram has excellent working times and does not require redirection of the operatory lights. Immediately following this step, the Tetric EvoCeram Translucent shade was placed to build the restoration to full contour, and the margins were smoothed and blended into the tooth structures with a sable hair brush and light-cured for 10 seconds (Figure 7). The rubber dam was removed, and the occlusion was checked and adjusted with a football carbide bur (Brasseler, www.brasselerusa.com). The final polish was achieved with cups (OptraPol NG, Ivoclar Vivadent) (Figure 8).
The innumerable choices available for composite systems, along with the equal multitude of ceramic systems, can make material selection confusing. While the use of composite for minimally sized restorations is more obvious, the challenge comes in choosing a material when restorations are moderately large in size. Parameters such as strength and durability are coupled with patient factors such as time and cost. The ideal material would be one that could satisfy all these requirements while offering conservation of intact enamel and dentin. Tetric EvoCeram has proven to deliver the strength and durability with predictable results.
About the Author
Amanda Seay, DDS
Mount Pleasant, South Carolina