Dental veneers are custom-made, ultra-thin shells designed to cover the front surface of a tooth. These cosmetic restorations improve the appearance of teeth that are discolored, chipped, misaligned, or have small gaps. By masking imperfections, veneers provide a uniform and brighter appearance that mimics natural tooth enamel. Fabrication involves either a laboratory procedure or a direct, chairside application, which dictates the materials and manufacturing steps used to achieve a durable and aesthetic result.
Primary Materials Used in Fabrication
The selection of material forms the foundation of the veneer’s final properties, largely falling into two main categories: ceramic and composite resin. Ceramic veneers are typically made from glass-ceramics such as lithium disilicate or feldspathic porcelain, prized for their exceptional translucency. Lithium disilicate is a particularly strong glass-ceramic, known for high fracture strength due to its crystal structure. This composition allows for the creation of very thin, robust veneers that imitate the optical depth of natural enamel.
Composite resin veneers utilize a blend of organic and inorganic components, primarily consisting of a polymer matrix mixed with fine filler particles, often glass or silica. This material is more opaque than ceramic options but is valued for its ease of manipulation and ability to be quickly shaped. Composite resin is more cost-effective and simpler to repair, but it is less stain-resistant and durable than ceramic materials.
The Indirect (Laboratory) Fabrication Process
The indirect method typically uses durable ceramic materials like lithium disilicate or porcelain. The process begins after the dentist prepares the tooth and captures a precise record of the surface using a traditional impression or an intraoral digital scanner. This digital or physical model is then sent to a dental laboratory, where the fabrication process begins with the design phase.
In a digital workflow, the scan data is imported into Computer-Aided Design (CAD) software, where a laboratory technician precisely models the final shape and contour of the veneer. This digital blueprint is then sent to a Computer-Aided Manufacturing (CAM) unit, which uses a subtractive process to mill the restoration. A specialized milling machine carves the veneer from a solid block of pre-crystallized ceramic, such as lithium metasilicate, with extreme precision.
Following milling, the ceramic restoration is subjected to a high-temperature firing process to achieve its final strength and color. This heat treatment recrystallizes the material, converting softer lithium metasilicate into the much harder lithium disilicate, which significantly increases its flexural strength. Alternatively, for traditional porcelain materials, technicians may use a layering technique, applying ceramic powder onto a refractory model that is then fired in a furnace.
Another technique, known as the press method, involves injecting softened ceramic material into a mold created from the wax-up of the final veneer shape. After the high-heat fabrication is complete, the veneer’s surface is refined, and custom stains or glazes are applied to mimic the natural characteristics and luster of tooth enamel. These finished restorations undergo a quality check to ensure a perfect fit before being sent back to the dental office for final bonding.
The Direct (Chairside) Fabrication Process
The direct fabrication process is completed by the dentist during a single office visit, using composite resin material. This method often requires less or no removal of the natural tooth structure. The dentist first ensures the tooth surface is clean and then applies the composite resin material directly onto the tooth.
The application is performed in layers, allowing the dentist to meticulously sculpt and shape the material to achieve the desired contour and anatomy. To mimic the appearance of a natural tooth, different shades of resin, or even small amounts of opaquers or tints, may be layered to control the restoration’s chroma and value.
Once the desired shape is achieved, a specialized high-intensity light is used to cure or harden the composite resin, a process called polymerization. This light-curing step chemically sets the material, transforming it into a durable solid shell. The final step involves a meticulous finishing and polishing sequence to smooth the surface and create a high-gloss, natural-looking shine that helps resist future staining.