Advances in cements have made them easier and more efficient to use.
Cements today bear little resemblance to the early prototypes. Newer resin-based cements require no mixing, come in a variety of shades and fit all clinical scenarios, according to Dr. Rolando Nunez, Bisco, Inc. Their biocompatibility, low solubility and enhanced physical properties have made them more reliable, he points out. State-of-the art calcium-releasing cements are designed to stimulate apatite formation and bond to metal and zirconia surfaces, without the assistance of primers. And, auto-mix syringes are easier – and cleaner – to use.
“Clinicians depend on cements to be as versatile as possible,” Nunez continues. “A cement must be easy to use, easy to mix and easy to dispense,” he says. The more versatile the cement, the fewer products clinicians must stock in their armamentarium. “Versatility translates to economic benefits, as one or two cement products should be enough to address all clinical scenarios.”
Selecting the right cement
A working knowledge of cements enables clinicians to select solutions that best meet the needs of their practice. Film thickness, work and setting time, compatibility and the ability to determine whether surfaces must be primed prior to using the material all factor into the final choice. And, depending on the type of restoration, they must understand how the curing mechanism will affect the final performance.
“Cements should be stable, meaning the working and setting time should not be impacted by storage conditions,” says Nunez. Additionally, they should be:
- Easy to clean to avoid excess cement subgingivally and interproximally, which can lead to periodontal issues.
- Insoluble and stable in intraoral conditions.
- Able to achieve proper film thickness (less than 50 microns) to avoid interfering with proper seating of the restorations.
“Post-op sensitivity is usually related to the bonding procedure and pulp protection rather than the cement itself,” he adds.
There are two major categories of cements used in dentistry, according to Nunez: resin-based and nonresin-based. “Resin-based cements can be less soluble than resin modified glass ionomers (RMGI) due to their higher resin content,” he says. “Regular glass ionomers (GI), in turn, are more soluble than resin-based and RMGI cements. Resin-based cements also have better physical properties than glass ionomers – again due to their higher resin content. Bonded resin-based cements require the use of a dental adhesive as part of the cementation procedure, whereas GI and RMGI cements do not.”
Resin-based cements include both self-adhesive and bonded cements. With self-adhesive cements, there is no need to use a bonding agent prior to the cementation procedure, Nunez explains. Bonded resin-based cements, on the other hand, require a dental adhesive to be applied to the preparation prior to the cementation procedure. “The adhesive must be compatible with the cement in order to avoid polymerization hindrance,” he notes.
“Based on the polymerization mechanism, hydroscopic expansion, pH and shade, cements will have different clinical applications,” says Nunez. “In general, dual cured resin-based cements and RMGIs can be used for full-coverage restorations, such as crowns and bridges. For esthetic demanding restorations, such as veneers, a light cured resin-based cement is preferred. Based on the restorative material, any cement will work on metal-based restorations. For ceramic materials, a surface treatment is required for optimum bonding; thus, a resin-based material is better suited for such treatments.
With the right cement solution, dental practices can provide their patients with long-lasting, esthetically pleasing results.