Sam Simos, DDS, focuses on advances in composite resin materials for today’s dental practices.
Q: How do dentists choose a composite material?
A: Surprisingly, across the country, when asked how dentists choose the composite material they are using, few can point out any one reason. Most say that it is what they have been using for years. Some say that a sales rep or colleague suggested it. Only a handful will talk about exploring the chemical and physical properties inherent in a specific material. In fact, few dentists are able to name one physical or chemical attribute of the composite resin that they are using.
Q: What are the top 3 characteristics a dentist should look for when choosing a composite material?
A: The primary characteristic that dentists consider is, indisputably, how the material handles. Is it creamy or stiff? How sticky is it? The importance placed on a composite’s handling qualities is not surprising. After all, time can be either saved or wasted on a direct restoration depending on the clinician’s tactile comfort with a given material. It appears to be an even 50/50 split between preferences, and manufacturers recognize this: many offer their products in both high- and low-viscosity formulas to suit clinicians’ preferences. Metamerism and polish ability rank next on the list, but manufacturers have had a much easier task of supplying materials that perform agreeably in regards to both of these aspects.
Q: What are the biggest advances in composite technology in the last 5 years?
A: From a historical standpoint in the dental profession, no material—except possibly all-ceramic restorations—has experienced as much innovation as the composite resin. One of the most recent and notable advancements is the development of the nanohybrid composite: a material comprised of both microfilled and hybrid composites. This marriage of small and large filler molecules has given way to a superior class of composite resin material that demonstrates greater strength, durability, and aesthetic qualities. Nanohybrids are suitable candidates for almost any restoration, exhibiting less shrinkage within the material so that cuspal stress is minimized and patient sensitivity lessened. The adhesive properties of nanohybrids also curtail the need for additional preparation of the tooth in most cases, which equates to a higher conservation rate of existing tooth structure. Also, consider that nanohybrids yield excellent aesthetic results. Its appearance is so close to the natural color of teeth that the restoration can appear seamless. In addition, the polishing qualities are more than desirable, and the high-gloss finish can endure for years and is even enhanced by tooth brushing.
Q: What are some of the biggest advances in the recent evolution of flowable composites?
A: Flowable composites have undergone extensive reformulations in recent years and can be used in a much wider range of clinical applications. No longer limited to Class V restorations, they are now manufactured to withstand substantial occlusal wear and tend to exhibit higher strength, less shrinkage, and better retention of the final polish. This newfound versatility is a remarkable advancement because it provides the dentist with more clinical options when performing a direct restoration. Furthermore, because of the viscous nature of flowable composites, most have the tendency to self-level during application, essentially making handling a nonissue.
Q: Bulk-fill composites are trending right now. Please explain what these are and why they are gaining in popularity.
A: Bulk-fill composites are aptly named because they are a class of composite resins that are used and light cured in larger bulk-filled increments. While universal composites must be light cured in 2.0-mm increments, a bulk-fill composite may be cured in 4.0- to 5.0-mm increments. This can save the dentist a significant amount of time, especially with larger restorations. The increased depth of cure is accomplished by the translucent nature of a bulk-fill, which allows light to penetrate further than the more opaque conventional composites. Bulk-fill composites typically have a decreased percentage of filler particles too, resulting in a viscosity that readily conforms to the walls of the tooth with minimal handling. Note that while the translucency and filler volume lend great advantages to direct restoration placement, most bulk-fills require an enamel-capping layer of conventional composite to address the aesthetic aspect of the restoration.
Q: We have come so far in composite technologies. Where do you see the next advancement in composite materials?
A: The majority of research being conducted for composite technology is aimed at optimizing the longevity of direct restoration materials. The development of a novel formulation (or reformulation) that begets reduced shrinkage and better wear could help tremendously in negating the occurrence of direct restoration failures. And, as with any biosynthetic material, scientists continue to strive for composite formulations that can closely mimic or even outperform the body’s natural resources. To that end, one direction of research currently centers around a composite material that can actively work in the patient’s favor for years after placement. These composites would have antimicrobial properties to combat bacterial growth around the margins of the filling, thus preventing secondary decay in the restored cavity. Another avenue of research focuses on a composite material that would release fluoride ions to help with the remineralization of compromised tooth structure in the surrounding area. But perhaps a more tangible benefit for clinicians would be producing a composite that does not rely so heavily on repeated light curing. The light would serve only as the initiator in the polymerization process, leaving the material to proceed with self-polymerization sans any additional curing. In any case, the future of composite technology is extremely promising, and that will only serve to further please clinicians and patients alike!
Dr. Simos maintains private practices located in Bolingbrook and Ottawa, Ill. He received his DDS degree at Chicago’s Loyola University and is the founder and president of the Allstar Smiles Learning Center and client facility (Bolingbrook). He can be reached via email at sam.s@allstarsmiles.com or by visiting allstarsmiles.com.
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