Nanohybrid composite restorations: Dentistry's most versatile solution

by Bruce J. LeBlanc, DDS

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In today's uncertain economy, patients often seek alternative solutions to dental problems that best fit their financial condition. No material available in my practice allows me to offer as many practical options as nanohybrid composites.

The evolution of composites initially created two families of materials. Microfilled composites with smaller particle fillers allowed better polish retention while enhancing esthetics, but offered less strength. Thus, they were chosen primarily for esthetic-driven anterior restorations. Hybrid composites blended in larger particle fillers to improve strength but were less polishable, resulting in more of a matte rather than gloss finish. They were chosen for their durability for posterior restorations in which strength was essential.

The latest generation of nanohybrid composites, introduced to the market several years ago, combine the best of both materials and create durable restorations that maintain a gloss shine for many years. This is important for maximized esthetics, as well as reduced plaque accumulation. The clinical success of hybrids, such as Tetric and Herculite, has paved the way for development of their nanohybrid siblings. These include Premise and Herculite Ultra.

The addition of nanoparticles to hybrid mixtures has created a truly universal product, suitable for all clinical composite applications, maximizing durability and polishability. When properly placed, nanohybrid composites offer many benefits. These include:

1) Minimal removal of tooth material is required since adhesive properties allow adding material to defective areas without the need for additional preparation. Patients love the concept of conserving tooth structure, referred to by some as “tooth banking,” when their teeth are restored. They consider these options as advances when compared to alternative crowns that involve considerably more tooth removable to make room for the thickness of the restoration and retention.

2) Lab-processed restorations can offer the highest potential for longevity of service; however, expenses associated with lab fees and multiple appointments increase their cost. This might create a bad financial fit for a patient's economic condition. Direct nanohybrid composite restorations, on the other hand, can result in an immediate cost savings of as much as 50% to 80% when provided in lieu of crowns. This eliminates expenses for lab fees and crown buildups where indicated. The savings make it a better fit for some patients, especially when multiple restorations are involved.

3) Since nanohybrid composite restorations are completed in one appointment, patients need anesthetic administration only once. This also saves the time and inconvenience required for a separate cementation appointment.

4) Nanohybrid composites can be polished to a high- gloss finish that will be retained for many years. This ensures optimum esthetics resembling natural teeth with minimal plaque accumulation. The gloss of these materials can be enhanced by tooth brushing in what I refer to as a “self-polishing effect.” As a result, the luster is maintained by patient home care during daily brushing, and can look as esthetic at recalls as when originally placed.

5) Ease of color matching due to the natural appearance of nanohybrid composites maximizes esthetic results. The material blends seamlessly into the teeth being restored, showing no evidence of the repaired area and without looking prosthetic. This often can be a challenge with porcelain, whereas nanohybrids have a chameleon effect that camouflages the restoration in a way that appears like the natural tooth.

6) Nanohybrids create more tools to solve multiple problems for patients. When stress factors are favorable, immediate single-tooth replacement can be accomplished with direct composite bonding without the need to remove additional tooth structure. This is especially advantageous for younger patients where implant dentistry may not yet be indicated due to patient age or economic condition.

Although nanohybrids are universal in use for anterior and posterior restorations, I have chosen to illustrate a multisurface molar restoration. Strength and adhesive properties of nanohybrids make them ideal for repair of posterior as well as anterior teeth.

A patient's large amalgam was failing in a lower right first molar (Fig. 1). This was removed, creating a considerable residual defect. Traditionally, the option of a crown buildup, combined with a lab processed restoration, may be recommended. In our office, we use digital photography to consult with patients, showing images of their condition along with treatment solutions. We offer choices of solutions used for other patients with similar needs.

We discuss alternatives in a way that is nonthreatening and allows the patient to choose and “own” the outcome. For this case, a nanofilled direct composite was a better fit for the patient's economic situation since immediate costs were less and we had the ability to conserve the tooth walls that would have been removed during preparation for a crown. The technique involved removal of the amalgam and decay related to leakage.

Fig. 2: The tooth has been prepared and the matrix is in place. Note that the walls of the tooth have been retained with a minimally invasive preparation.

A greater curve band matrix was used for restoration fabrication (Fig. 2). This matrix seals the gingival margin of the preparation, eliminating sulcular fluid contamination while creating a perimeter form to mold the restoration. Other sectional matrix systems, such as V Ring and Compositite 3D, are also tools to use when interproximal repairs are necessary.

Following proper bonding protocol with a rinse-etch bonding technique, the tooth was properly etched with phosphoric acid, rinsed, and dried as per manufacturer recommendations.

In this case, a fourth generation multibottle bonding resin, such as Optibond FL or Clearfil SE, was used to seal the dentin and create adhesion.

It has been my experience that proper adhesive application should eliminate any sensitivity and result in no immediate white, or eventually brown, margin issues. Next, we used a nanohybrid composite, such as Herculite Ultra or Premise, to rebuild and mimic natural tooth structure while sealing and strengthening the tooth.

Fig. 3: The completed nanohybrid restoration restores strength and esthetics of the tooth while mimicking the tooth in function and wear. A high-gloss finish will be maintained due to the formulation of the material.

Due to wear and esthetic characteristics, the final restoration blends in esthetically, feels natural, and adhesively strengthens the tooth (Fig. 3). Our patient valued that it was completed in one visit, minimized tooth removal, and saved immediate costs.

Properly placed composite restorations that use new-generation nanohybrids can offer opportunities to match restorative solutions to the economic condition of patients.

Although lab-processed restorations potentially last longer, well placed composites can offer a tremendous value with a cost savings that is appreciated when it is presented as an option for patients.

These restorations can give many years of durable service, be easily repaired or resurfaced, and serve as a structural buildup — if necessary — for a future date.

I see this as a “win-win” situation. Patients do, too.

Dr. Bruce J. LeBlanc provides seminars nationally on minimally invasive adhesive solutions to dental problems. He has published internationally and is course director and presenter for “Simplified Esthetic Solutions Your Patients Will Love” at LSU School of Dentistry. Dr. LeBlanc may be reached by e-mail at [email protected].