Naturally Protecting Marginal Integrity
Arthur R. Volker, DDS, MSEd, on Calibra® Bio cement
There are a wide variety of ceramic restorative options available to the clinician as well as multiple options for cementation. The advent of higher strength fixed prostheses made from materials such as high-translucency zirconia has allowed for the use of conventional luting cements for restorations. These cements are often less technique sensitive because there are fewer steps required. They are also more forgiving in the presence of physiologic moisture when compared with adhesive resin cements.
In the realm of modified glass-ionomer cements, Calibra Bio® is a game changer. Con-taining no resin-which is more moisture sensitive-Calibra Bio is a conventional luting cement based on calcium aluminate ionomer chemistry. When exposed to the phosphate ions that naturally occur in saliva, the calcium aluminate helps in the formation of hydroxyapatite at the preparation's margin, which helps to protect marginal integrity by minimizing microleakage.
As a traditional glass ionomer cement sets, small marginal discrepancies can develop at the interface between the tooth and the restoration. The calcium aluminate particles in Calibra Bio release calcium and aluminate ions that can then crystallize around the remaining non-dissolved calcium aluminate particles, which helps to create a seamless adaptation at the interface. As the restoration ages, if any damage occurs, saliva in the oral environment interacts with the cement at the margins to continuously repair the hydroxyapatite layer and maintain the overall marginal integrity.
Calibra Bio cement is easy to use. There is no need to etch, prime, or bond the tooth; however, metal oxide ceramics should be sandblasted with 50-μm alumina particles, according to the manufacturer's instructions, to increase the surface area available for cementation. In addition, there is no need for universal cleaning paste because, unlike bonding protocols involving primers and resin cements, Calibra Bio cement works well in the presence of phosphates. The cleanup of excess cement can be initiated approximately 2 minutes after mixing, when the Calibra Bio cement reaches a rubber-like consistency. It fully sets within 6 to 8 minutes of mixing, and research has shown that it exhibits the same long-term retentive strength as self-adhesive resin cements.
In conclusion, the use of modified glass ionomers offers clinical advantages over the use of other categories of cements, the greatest of which are related to their excellent bioactivity. In clinical situations where isolation becomes a challenge, Calibra Bio cement can be used routinely for the cementation of all full-coverage metal-oxide restorations, offering the clinician a reliable cementation protocol for the majority of clinical cases.
• Facilitates simplified bioactive cementation for metal-oxide ceramics with adequate retention form
• Forms a self-repairing hydroxyapatite layer that protects marginal integrity
• Creates seamless adaptation at the cement-tooth interface
• Requires no priming, bonding, or conditioning, so it is easy to use and clean up
About the Author
Arthur R. Volker, DDS, MSEd
Academy of General Dentistry
Sunnyside, New York