Table of Contents

Practice Building
Roundtable
Implants

Inside Dentistry

May 2011, Volume 7, Issue 5
Published by AEGIS Communications

Replacing Amalgam with Composite

Achieve long-term performance with Tetric EvoCeram.

By Edward Lowe, BSc, DMD

Used for more than 50 years and now replacing amalgam as the restorative material of choice by many dental professionals, composite materials now comprise more than 95% of all anterior restorations and 50% of all posterior restorations.1 Demonstrating improved esthetics, composite restorations are nearly indistinguishable from the surrounding natural dentition when placed properly.1,2 However, many composite materials have historically demonstrated issues such as excessive polymerization shrinkage and marginal leakage that can lead to problems for the patient, including sensitivity, secondary caries, and restoration failure, among others.3 Today, many manufacturers promise the best in esthetics, function, and longevity, along with lower polymerization shrinkage rates and a reduced risk of marginal leakage. While conventional and newer composite materials sometimes fall short of these promises, today's composite materials offer promising results due to their constant state of evolution.2

With an overwhelming number of composites available, it is important that the proper materials and treatment plans are chosen based on case requirements.3 For example, although some materials may be suitable for anterior restorations, they may not meet the requirements for posterior restorations.4 Additionally, some composites are considered appropriate for restorations in both the anterior and posterior, but require specific preparation techniques for each region to reduce the risk of polymerization shrinkage and marginal leakage.4-6 When choosing a material, it behooves dentists to carefully consider how quickly the material will react to ambient light. Some materials may have a tendency to polymerize too quickly under ambient light (ie, operatory light) before the placement and contouring process is complete.7

Through the development of innovative nano-optimized formulations, dental manufacturers have worked to resolve many issues typically experienced with conventional composite materials. These newer materials have proven successful for replacing failing amalgam restorations with minimal loss of excess tooth structure.8

Tetric EvoCeram

An innovative nano-optimized universal hybrid composite material (Tetric EvoCeram, Ivoclar Vivadent, www.ivoclarvivadent.com) provides dentists with the ability to contour composite restorations for an extended length of time while maintaining a fast curing time. Additionally, a more natural shade blend is achieved by the matched refractive indexes of the fillers and monomers to further simplify shade selection. Among these innovative features, Tetric EvoCeram also displays high radiopacity, low polymerization shrinkage, low shrinkage stress, and low wear.

Ease of placement is a function of the material's working time and handling properties. A special additive incorporated into the photoinitiator system of Tetric EvoCeram causes the material to be less reactive to ambient light while remaining highly reactive to curing lights. This provides extended working time to fully contour the restoration while still allowing for fast polymerization. A special nano-modifier incorporated into the resin matrix optimizes the handling properties of Tetric EvoCeram and provides stability of contoured anatomy prior to polymerization. This combination of extended working time, on-demand polymerization, and stabilizing modifiers provides dentists with much more control over the placement of their composite restorations.

A composite material's ability to blend with the shade of the surrounding dentition leads to faster, more efficient processing. The refractive indexes of the fillers and the monomer in Tetric EvoCeram are matched increasing the material's translucency before shading resulting in a near-perfect match with the surrounding dentition. This technology allows for high-level esthetics to be achieved with a single shade of Tetric EvoCeram.9 Available in three levels of translucency, including Dentin, Enamel, and Transparent, Tetric EvoCeram offers dentists a variety of esthetic options for restorations in both the anterior and posterior regions.9

Choice of delivery options can be dictated by the specific location of the restoration. Tetric EvoCeram is available in both syringes and unit-dose Cavifils. For posterior applications, the Cavifils tend to be a better choice of delivery forms as the longer tips facilitate easy placement of the composite material into hard-to-reach areas, such as molars.10 Additionally, Cavifils can be rotated 360° in the injector, so regardless of the jaw position, the material can be easily dispensed directly into the cavity preparation.10 Following a color-coded system, the syringe labels and Cavifil caps of Tetric EvoCeram are clearly marked to ensure proper shade identification and selection.9

Composed of a unique blend of nano-sized filler particles, Tetric EvoCeram demonstrates many advantages over traditional composite formulations as well as long-term clinically proven durability. Ceramic fillers promote excellent strength, superior polishing properties, sustained gloss, and low wear. Because the material demonstrates lower wear than other conventional composite materials, the need for replacement is greatly reduced. With exceptionally low shrinkage rates (<1.6%) as a result of prepolymers and low shrinkage stress, restorations completed with Tetric EvoCeram promote better marginal integrity.9 Finally, the patented filler ytterbium trifluoride produces the composite's high level of radiopacity, which research has shown is critical for providing a sound diagnosis.11 This unique formulation results in an excellent balance of physical properties, making Tetric EvoCeram an excellent choice for direct anterior and posterior restorations.

The following case demonstrates the use of Tetric EvoCeram to replace failing amalgam restorations in the posterior region in teeth Nos. 30 and 31.

Case Presentation

A patient presented with occlusal amalgam restorations on teeth Nos. 30 and 31 that were failing, causing secondary caries (Figure 1). The treatment plan would include removal of the amalgam restorations and caries, followed by placement of an innovative nano-optimized universal hybrid composite (Tetric EvoCeram).

Placement Technique

Initially, a rubber dam and a matrix were placed, followed by the removal of the old amalgam and caries (Figure 2). The preparations were then etched for 15 seconds on the enamel, followed by 10 seconds on the dentin (Figure 3), after which a single component adhesive (ExciTE, Ivoclar Vivadent) was placed (Figure 4). After air-drying and light-curing the adhesive, a nano-optimized, medium-viscosity flowable composite (Tetric EvoFlow, Ivoclar Vivadent) in shade A3 was placed on the floor of the preparations and cured (Figure 5).

A nano-optimized universal hybrid composite material (Tetric Color), in Dentin shade A3, was then carefully placed and built onto each cusp, ensuring that the material was left 1 mm short of the cavosurface to leave room for the Enamel shade (Figure 6). Using a #10 endodontic file, Ochre and Dark Brown shades (Tetric EvoCeram) were then dragged to create groove stains (Figure 7). The material was then cured.

After curing, Bleach Incisal shade (Tetric EvoCeram) was placed with a P1 carver to further build the cusps and then cured (Figure 8 and Figure 9). Prior to finishing and polishing, Bleach Incisal shade (Tetric EvoFlow) was painted around the margins and cured (Figure 10). Finishing was then completed using fine diamonds and carbides. To give the restorations a final polish, silicone polishers filled with micro-fine diamond crystallites (OptraPol NG, Ivoclar Vivadent) and brushes were used. The occlusion was then checked with articulation paper, and the restorations were polished one last time.

Upon completion of the case, the new nano-optimized universal hybrid composite restorations demonstrated excellent esthetics and function, without excess polymerization shrinkage or marginal pull (Figure 11). Overall, the patient was very pleased with the way the Tetric EvoCeram restorations blended flawlessly with the surrounding natural dentition (Figure 12).

Conclusion

Using innovative formulations and advanced nano-optimized materials, the dentist in this case was able to provide a solution to the patient's failing amalgam restorations in the posterior region. Demonstrating excellent esthetics and improved function, Tetric EvoCeram met the case requirements and eliminated the risks of excessive polymerization shrinkage and potential marginal leakage.

Through their evolution and advancements in material sciences, direct composites are becoming the material of choice for restorations in both the posterior and anterior regions.1,2 With unparalleled esthetics and now the longevity to match, dentists can be sure that the composite restorations they place will last just as long—if not longer than—the conventional amalgam materials of the past.1,2

References

1. Stein PS, Sullivan J, Haubenreich JE, Osborne PB. Composite resin in medicine and dentistry. J Long Term Eff Med Implants. 2005;15(6):641-654.

2. Minguez N, Ellacuria J, Soler JI, Triana R, Ibaseta G. Advances in the history of composite resins. J Hist Dent. 2003;51(3);103-105.

3. Malhotra N, Kundabala M, Shashirashmi A. Strategies to overcome polymerization shrinkage – materials and techniques. A review. Dent Update. 2010;37(2):115-125.

4. Ritter AV. Direct resin-based composites: current recommendations for optimal clinical results. Compend Contin Educ Dent. 2005;26(7):481-490.

5. Blank JT, Latta M. Composite resin layering and placement techniques: case presentation and scientific evaluation. Pract Proced Aesthet Dent. 2005;17(6):385-390.

6. Ferrari P, Veneziani M. A comparison of various adhesive composite restorations in the posterior regions. Pract Proced Aesthet Dent. 2007;19(8):503-509.

7. Ensaff H, O'Doherty DM, Jacobsen PH. Polymerization shrinkage of dental composite resins. Proc Inst Mech Eng H. 2001;215 (4):367-375.

8. Sardenberg F, Bonifácio CC, Braga MM, Imparato JC, Mendes FM. Evaluation of the dental structure loss produced during maintenance and replacement of occlusal amalgam restorations. Braz Oral Res. 2008;22(3):242-246.

9. Tetric EvoCeram®. (2009). Nano-optimized composite restorative. [Brochure]. Ivoclar Vivadent, Amherst, NY.

10. Ivoclar Vivadent USA. Clinical Accessories/ Instruments—Cavifil Injector. 2010. Available at: http://www.ivoclarvivadent.us/content/products/detail.aspx?id=prd_t1_1075236776&product=Cavifil+Injector.

11. Tetric EvoFlow®. (2007). Nano-optimized composite restorative. [Brochure]. Ivoclar Vivadent, Amherst, NY.

About the Author

Edward Lowe, BSc, DMD
Private Practice
Vancouver, BC, Canada