As evidence continues to mount showing that the lifespan of composite restorations is incredibly short (5.7 years, according to the National Institutes of Health), the need to improve marginal integrity has become more and more apparent. The causes of failure with traditional materials and methods are multifactorial.
First, we’ve known for years that composites are incredibly brittle and easily fail over time. Second, we’ve seen marginal gaps that occur during polymerization of composites. Researchers recently noted that oral bacteria can attach to the most commonly used composite materials, leading to greater degradation. Finally, we’re seeing what I interpret as a rejection of the hybridization layer via natural enzymatic defense responses of tooth pulp to the hybridization process. This response leads to destruction of the collagen makeup of the dentin, which ultimately leads to composite-dentin interface failure. When you put all that together—degradation of collagen, brittle nature of composites, and marginal gaps that create a haven for bacteria—hybridization can’t succeed long-term.
As this becomes more and more apparent, we’re going to be faced with some tough questions. Don’t you want to be ready with the answer? In other words, don’t you want to have bioactive/biomineralization materials in your restorative armamentarium?
Last August, I attended “Biomaterial Summer School” at the University of Turku in Finland. Much of the discussion focused on the need to consider alternative methods to improve the longevity of direct restorative and adhesive materials. The consensus was that change is needed with materials that provide a readily available source of calcium and phosphate that can be easily released from restorative materials without degrading the physical properties of the restoration. These ions can be released only from hydrophilic materials, making them true bioactive materials with the potential to stimulate hydroxyapatite formation. These elements are the key to restorative longevity.
?Several dental manufacturers offer bioactive materials as bases, liners, and cements, and one company has a restorative material that fi ts the true defi nition of bioactive. As we better understand the benefi ts of bioactive materials, we’ll see a surge of new products to fi ll the growing demand for dental materials that provide patients with restorations that contribute to long-term function and esthetics.
Change is inevitable as we learn from our mistakes and seek the next improvement in how we provide dental care. The world of dental materials is changing, leading us to greater restorative longevity.
John C. Comisi, DDS, MAGD
In private practice in Ithaca, NY, since 1983, Dr. Comisi is a graduate of Northwestern University Dental School and received his Bachelor of Science in Biology at Fordham University. He has lectured nationally and internationally and has contributed to dental literature. Dr. Comisi is a member of the Dental Product Shopper Editorial Advisory Board and a member of the National Dental Practice-Based Research Network as well as the International and American Association of Dental Research. For his lecture schedule and CE presentations, visit thepracticaldentist.com.