Dental cement is an adhesive material that forms the bond between a prepared tooth structure and a prosthetic dental restoration. It secures items like crowns, bridges, and veneers permanently in place.
This bonding agent ensures the long-term mechanical stability and marginal seal of the final restoration. Without this specialized cement, the artificial structure could not withstand the daily forces of chewing.
Color Range of Dental Cement
The color of dental cement is not standardized but exists across a wide spectrum engineered to meet varying aesthetic needs. For non-aesthetic applications, such as securing metal or metal-fused-to-porcelain crowns, the cement may be an opaque white or a pale yellow shade. This opacity is often desirable to block out the darker color of the underlying metal substructure.
Modern aesthetic dentistry relies heavily on cements that are translucent, or nearly clear, allowing light to pass through them. The cement’s translucency is frequently more important than its actual hue. Manufacturers offer kits containing multiple shades, including lighter, darker, and neutral options, to fine-tune the final appearance of a restoration.
Primary Types of Cement and Their Composition
The aesthetic properties of dental cement are directly linked to its chemical composition, which dictates its strength, translucency, and clinical application.
Resin Cements
Resin cements represent the highest standard for aesthetic control, as they are polymer-based materials that set through a polymerization process. They are available in a broad range of shades, allowing them to be color-matched precisely to the final restoration. Resin cements are the preferred choice for thin, translucent ceramic veneers.
Glass Ionomer (GI) and Resin-Modified Glass Ionomer (RMGI) Cements
These cements are tooth-colored but offer fewer shade options and less translucency than pure resin cements. GI cements are water-based and chemically bond to the tooth structure while also releasing fluoride. RMGI is a hybrid that incorporates resin components to enhance strength and reduce solubility. These are generally more opaque and are primarily used for routine crowns in posterior, less visible areas.
Traditional Cements
The third group comprises traditional materials like Zinc Phosphate and Zinc Polycarboxylate cements. These are composed of powder and a liquid acid. These older cements are very opaque, often appearing as a chalky white or yellow. They are still used for cementing metal-based crowns and bridges where aesthetics are not a concern and mechanical retention is the main requirement.
Clinical Process of Shade Matching
For highly aesthetic restorations, the cement selection procedure is known as shade matching, performed before the permanent bond is created. When a restoration like a thin ceramic veneer is placed on the tooth, the color and opacity of the cement beneath it significantly influence the final appearance. Light passes through the thin ceramic, reflects off the cement, and returns to the eye, meaning the cement acts as the restoration’s background color.
To accurately predict the final result, the dentist uses specialized “try-in” pastes. These pastes have the identical color and translucency as the final cement but lack the adhesive component. The try-in paste is placed on the internal surface of the restoration, which is then temporarily seated on the tooth.
This temporary placement allows the patient and dentist to confirm the desired color match before committing to permanent cementation. If the shade is incorrect, the paste is easily rinsed away, and a different shade is tested until a natural and seamless blend is achieved. This step ensures the restoration integrates perfectly with the surrounding natural teeth in high-visibility areas.
Restorations That Require Dental Cement
Dental cement is employed across a wide range of procedures to secure indirect restorations that have been fabricated outside of the mouth. The most common applications include:
- Permanent bonding of dental crowns, which cover the entire visible portion of a damaged tooth.
- Securing fixed bridges, which replace missing teeth by being anchored to adjacent natural teeth or implants.
- Stabilizing less extensive restorations, such as inlays and onlays (partial crown coverings).
- Bonding highly aesthetic restorations like porcelain veneers, which require specific, highly translucent resin cements.
- Attaching orthodontic brackets and bands to the tooth surface using specialized cements.