Today’s Composite Resins Part 1: Versatile, Aesthetic, and Conservative

INTRODUCTION
Over the last 25 years, there has been a huge increase in the use of ceramic veneers and this has been a good thing.¹ Indeed, this procedure has done more than anything to establish what one manufacturer (Ivoclar Vivadent) has called the Esthetic Revolution.² However, if something is used to such a degree that it becomes the only tool in your toolbox, this can be a bad thing. Automatically defaulting to an indirect solution for all anterior aesthetic wants and needs can sometimes be a disservice to our patients. To become what I call a complete dentist means learning skills in all the modalities of restorative and cosmetic dentistry so we can fit the solution to the patient’s problem, instead of making the patient’s problem fit our solution.
Today’s patients want their dentistry more aesthetic but less invasive, and direct composite resin accomplishes both.³ Undoubtedly, many dentists may still be operating under the false impression that ceramic is the material of choice when maximum aesthetics is desired. This article will show how, with the introduction of the new naturally shaded composite systems (NSCS), this perception is no longer true. In the author’s opinion, this new class of composite resin materials has evolved to the point of virtually mimicking tooth structure. Once the structure of these systems is understood, the clinician will begin to achieve significantly improved aesthetic results and will discover the limitless versatility of these new materials.

Figure 1. The patient presented with an all-ceramic crown on an endodontically treated central incisor. He wished to improve the appearance and size proportion of both central incisors.	Figure 2. The patient’s left central was restored with an all-ceramic crown (Empress [Ivoclar Vivadent]), and the right central was veneered with composite resin (Empress Direct [Ivoclar Vivadent]).
Figure 3. A 15-year-old female post orthodontics. Diamond abrasion and bleaching were attempted by a previous dentist.	Figure 4. Diode laser tissue lift and 6 direct resin veneers (Empress Direct) restored this patient’s smile to health and aesthetics.

Indeed, one recently introduced NSCS, Empress Direct (Ivoclar Vivadent), claims to offer “the esthetics of a ceramic with the convenience of a composite” and has almost eliminated the metameric effect usually seen between these 2 materials (Figures 1 to 4).⁴

NATURALLY SHADED COMPOSITE SYSTEMS
The author defines NSCS as one having the shades, opacity, and fluorescence of dentin; and the shades, translucency, and opalescence of enamel. From this definition, one would assume that only 2 opacities would be required to duplicate tooth structure. However, for many anterior applications this would not be quite true. Whereas dentin is uniform in opacity, enamel is not (Figure 5).

Figure 5. Dentin is uniform in opacity, enamel is not. Photo with permission from Professor L. Walsh, University of Queensland, Australia.	Figure 6. The enamel of the incisor shown here appears to have 2 distinct layers—an outer highly translucent layer, and an inner less translucent layer.

Figure 7. Author’s modified description of materials as dentin, enamel, and transenamel.

Looking closely, the enamel of the incisor in this image appears to have 2 distinct layers—an outer layer, which is highly translucent, and an inner layer, which is less translucent (Figure 6). Therefore, from a clinical application standpoint, to meet the true criteria of a NSCS, such a system would need to consist of 3 opacities. The author finds it easier when describing the opacities of the system to simply label them as dentin, enamel, and transenamel (Figure 7).

Systems Available and Common Attributes
Prior to the year 2000, the only composite resin that fulfilled the above definition of a NSCS, included a broad shade range marketed as a complete system with all 3 opacities, named the Renamel System (COSMEDENT). In this system, the dentin material is a hybrid composite, while the enamel and transenamel are microfils.⁵ Although the microfil ma­terial can be polished to a high shine (which is retained over time), its low flexural strength and fracture toughness require that it be layered over the dentin material in places of high stress (incisal edges). It is for this reason, that the dentin opacity is less (more translucent) than natural dentin and, in areas where more opacity is needed for block out, additional liquid opaquers are thus included in the system.
The introduction of Esthet·X (DENTSPLY Caulk) almost 10 years ago ushered in a whole new approach. This system was the first all-microhybrid composite resin system with a broad shade range containing 3 opacities that were intended to closely simulate the 3 opacities of tooth structure.⁶ Within a few short years, several other manufacturers introduced similar systems (Table 1).6

Recently, manufacturers have introduced a second generation of products (Table 1). These newer materials contain nanoparticles (individually and agglomerated) and some manufacturers have also modified the resin component slightly. In addition, shades and opacities were improved as needed.
Besides a broad shade range (most products have 30 or more shades), there are other important features common to all these systems, particularly in the second generation (Table 2). Obviously, each system achieves each of these features to a greater or lesser degree and the author will leave up to the clinician and independent testing to make the final judgment as to how close each manufacturer satisfies these desirable qualities. However, the author believes all these products will enhance a dentist’s ability to deliver durable and life-like restorations. In addition, there are other systems such as Gradia Direct (GC America), which come close to satisfying the author’s narrow definition of an NSCS. It should be noted that Renamel still qualifies as a NSCS. However, both the dentins and enamels are more trans­lucent than the nanomicrohybrid systems listed in Table 1, thus requiring the additional use of an opaque for some restorations.

Versatility

Figure 8. The diastema on this young patient kept returning following orthodontics.	Figure 9. The diastema was closed with direct composite resin by adding only to the proximal surfaces. No preparation was done.
Figure 10. This dental sales representative was self-conscious of her slightly shorter tooth No. 9. Note the worn canine tips.	Figure 11. After a slight roughening of the in­cisal 1.5 mm of enamel, the tooth was lengthened with a direct composite resin. The worn cusp tips on teeth Nos. 6 and 11 were replaced in the same manner to “protect” the incisal edge of No. 9 in left lateral excursive movement (4 Seasons [Ivoclar Vivadent]).
Figure 12. A single opacity restorative material can rarely effectively replace both dentin and enamel.	Figure 13. This young person was hit with a tennis racket fracturing the distal incisal edge of No. 8 and slightly chipping the mesial incisal edge of No. 9.
Figure 14. Tooth No. 9 was smoothed somewhat with a disc and the distal incisal edge of No. 8 was conservatively restored with direct resin (Renamel [COSMEDENT]).	Figure 15. This teenager was congentially missing tooth No. 11. Her mother asked what could be done about the diastema.
Figure 16. A 2-minute “mock-up” quickly shows the patient what can be done in an “additive without subtractive” procedure using direct composite resin.	Figure 17. A serviceable but old and unaesthetic Class IV restoration.

There is no question that the glamour and excitement of cosmetic dentistry today is the complete smile makeover using all-ceramic veneers. The effect is dramatic and rewarding for both the patient and the dentist. However, I believe the vast majority of practices have many more patients with minor to moderate imperfections. These patients may not be interested in a complete smile makeover, but may very well be interested in the kind of smile enhancement that can be achieved simply, predictably (when one knows how), and immediately with direct composite resin. This type of smile “upgrade” has the additional advantage of being accomplished conservatively, often with little or no preparation. Frequently, fewer teeth (or just parts of teeth) can be treated and, since there is no laboratory fee, there is less cost for the patient. I call this “nip and tuck” dentistry and there is lots of it in every practice (Figures 8 to 11).
In the past dentists often avoided asking the patient if they would like something done about these minor (in our mind) situations, because we lacked the predictable materials or skill (or both) to improve things. If the patient asked, we either downplayed the problem to avoid having to do something or, if forced to treat, we reached for our single opacity “universal” shade composite resin and hoped that we could achieve an acceptable result (Figure 12). Sometimes, in the case of chips or small fractures, we could achieve a slight improvement by modifying (enamelplasty) the affected teeth with a bur or a disc. However, the result was often a compromise. Today, a better aesthetic result can be achieved by a combination of enamel contouring and restoration with a NSCS (Figures 13 and 14).
Today, whenever defects that can be improved with direct resin are observed, it’s routine in the author’s practice to quickly apply and cure composite in a direct mock-up in order to let the patient see what’s possible (Figures 15 and 16). Patients almost always choose to have the service done because a nice smile has a high value in today’s society.
Besides elective “nip and tuck” cosmetic services, many patients are asking to have serviceable, but notice­able, Class III, IV, and V res­torations replaced (Figure 17). The fact is that the aesthetic standard is higher today, and what was once “good enough” is not. Even patients who don’t ask are frequently interested in having what was previously “good enough” dentistry “upgraded” when they are shown what can be done now (Figure 18). The versatile composite systems now available allow us to satisfy even the most discriminating patients.

Figure 18. The patient was pleased with a new life-like restoration. All 3 opacities plus blue-gray tint were used (4 Seasons).	Figure 19. This 9-year-old boy fractured his central incisor in an accident.
Figure 20. After very minimal preparation, all 3 opacities of composite as well as tints (4 Seasons) were used to add back the missing tooth structure.	Figure 21. A 14-year-old female with a prominent white spot on her right central incisor.
Figure 22. This “smile upgrade” was done with a conservative approach (Empress Direct).	Figure 23. Influence of a white spot on full-face appearance.
Figure 24. This small treatment has a big effect on overall image. Note the patient underwent tooth bleaching prior to placing the restoration.	Figure 25. This 38-year-old female desired aesthetic improvement of vital tooth No. 8.
Figure 26. Communicating the shade as well as the numerous maverick colors to a dental technician would be challenging using an indirect veneer. In the direct approach the adjacent tooth is the model for the dentist using composite resin, along with an opaquer and tints (4 Seasons).	Figure 27. This 26-year-old female was getting married in 3 days.

Figure 28. Direct resin veneers were placed on teeth Nos. 7 to 10 and cusp tips were restored on teeth Nos. 6 and 11 (4 Seasons).

Other situations, where a direct composite resin approach is usually better and less invasive than indirect treatment, are when treating injuries or imperfections in kids and young adults. We have to keep in mind that because of overall advances in healthcare as well as dentistry, these young people can be expected to live with their teeth well into their 80s, and possibly beyond! It is important for the dentist and the patient to understand that all dentistry is “temporary” and every time it is replaced, additional tooth structure is lost. So, for patients to keep their teeth over such a long life span, dentists need to avoid (whenever possible) the unnecessary removal of enamel at young ages (Figures 19 to 24). I recognize that the word “unnecessary” is a relative term and has to be decided on a case-by-case basis, but I think you will agree that it shouldn’t be decided by a lack of knowledge or training on the part of the dentist.
Certainly there are many clinical situations where either all-ceramic or direct composite resin will work well. In these cases, it is incumbent on the dentist to explain the advantages and disadvantages (each approach has both) of each type of procedure and material to the patient, and to help them make a choice. Factors such as cost, time, longevity, invasiveness, serviceability, and desired look or outcome are just some of the considerations that need to be addressed in detail. This information will assist the patient in making an appropriate and informed choice as to what is best for them. Besides achieving an outcome a patient wants, and how they want it, informed consent satisfies the ethical and legal requirements we have as healthcare providers (Figures 25 to 28).

CLOSING COMMENTS
Part 2 of this article will present case reports that illustrate the step-by-step clinical application of a recently introduced NSCS. The different clinical cases presented will help the clinician understand the layering rationale necessary to create life-like aesthetic restorations and cosmetic enhancements when using today’s advanced composite resins.

REFERENCES

1. Christensen GJ. Facing the challenges of ceramic veneers. J Am Dent Assoc. 2006;137:661-664.
2. IPS Empress marketing materials. Ivoclar Vivadent; 1991.
3. Christensen GJ. Veneer mania. J Am Dent Assoc. 2006;137:1161-1163.
4. Empress Direct marketing materials. Ivoclar Vivadent; 2009.
5. Renamel Restorative System Technique Manual. Chicago, Ill: Cosmedent; 2003.
6. Esthet·X Technique Manual. Philadelphia, Pa: Dentsply; 2004.

Dr. Jackson is a 1972 West Virgina University graduate and Fellow in the Academy of General Dentistry, an Accredited Fellow in the American Academy of Cosmetic Dentistry, a Diplomate in the American Board of Aesthetic Dentistry, and is director of the Advanced Adhesive Aesthetic Dentistry and Anterior Direct Resin programs at the Las Vegas Institute for Advanced Dental Studies. He has published many articles on aesthetic and adhesive dentistry, and has lectured extensively across the United States and abroad. Dr. Jackson has presented at all the major US scientific conferences. He maintains a private practice in Middleburg, Virginia, emphasizing comprehensive restorative and cosmetic dentistry. He can be reached at (540) 687-8075 or e-mail ronjacksondds@aol.com.

Disclosure: Dr. Jackson acted as a paid consultant for DENTSPLY Caulk and Ivoclar Vivadent during the development of Esthet·X and 4 Seasons respectively. He receives no income from the sales of any of the products mentioned in this article.