A dental crown is a custom-made, tooth-shaped cover placed over a damaged tooth. This restoration completely encases the entire visible portion of the tooth above the gum line. Its primary function is to restore the tooth’s original shape, size, and strength following significant damage. Permanently cemented into place, the crown provides a durable, long-term solution that also improves the tooth’s appearance and alignment.
Clinical Reasons for Needing a Crown
The decision to place a crown is made when a tooth has suffered structural damage too extensive for a standard filling. Crowns are frequently used to protect teeth that have undergone root canal therapy, as the procedure can weaken the remaining structure and make it susceptible to fracture. They also hold together the compromised parts of a severely cracked or fractured tooth, preventing further damage from chewing forces.
A tooth with substantial decay or a very large existing filling may lack enough healthy enamel to support itself, requiring a crown for reinforcement. Crowns are also utilized in prosthetic treatments, such as anchoring a dental bridge or covering the abutment placed over a dental implant. In some cases, a crown is recommended purely for aesthetic modification, covering teeth that are severely discolored, misshapen, or poorly aligned.
Material Options for Dental Crowns
Crowns are fabricated from various materials, each balancing durability and aesthetic appearance.
Metal Crowns
Metal alloys, often including gold, palladium, or nickel-chromium, represent the strongest and most fracture-resistant option. These crowns require the least amount of natural tooth reduction during preparation. They are highly favored for molars, where biting forces are greatest and aesthetics are less of a concern.
Porcelain-Fused-to-Metal (PFM) Crowns
PFM crowns combine the strength of a metal substructure with a tooth-colored porcelain coating. While offering good durability and natural appearance, the metal layer may result in a visible gray line at the gum margin. The porcelain layer also carries a risk of chipping and can cause wear on opposing natural teeth.
All-Ceramic Crowns
All-ceramic or all-porcelain crowns provide the most natural match to the color and translucency of surrounding teeth. Materials like E-max, a form of lithium disilicate, offer superior aesthetics and are frequently chosen for highly visible front teeth. Zirconia, a modern ceramic, is prized for its exceptional strength, often rivaling that of metal, while maintaining a tooth-colored appearance.
The Crown Placement Procedure
The process of receiving a conventional dental crown requires two separate visits to the dental office over a period of two to three weeks.
First Visit: Preparation and Impression
The first appointment begins with an examination, often including X-rays, to ensure the tooth’s root and surrounding bone structure can support the restoration. After administering local anesthesia, the dentist prepares the tooth by reshaping and filing down the outer enamel layer to create sufficient space for the crown material. The amount of structure removed depends on the crown material selected. An impression or digital scan of the modified tooth is then taken, capturing its precise dimensions and bite relationship.
This impression is sent to a dental laboratory, where skilled technicians custom-fabricate the permanent crown to match the desired shade and contour. Before the patient leaves, a temporary crown made of resin or acrylic is placed over the prepared tooth. This protects it from sensitivity and maintains alignment while the final restoration is being made. Patients should avoid chewing hard or sticky foods with the temporary crown to prevent dislodgement.
Second Visit: Cementation
During the second visit, the temporary crown is removed, and the underlying tooth is cleaned. The dentist checks the permanent crown for an accurate fit, proper bite alignment, and aesthetic match to the surrounding teeth. Once the fit is ideal and comfortable, the permanent crown is secured onto the tooth using a durable, specialized dental cement.
Maintaining Your Dental Crown
The longevity of a dental crown depends on consistent home care and professional maintenance. A crown is expected to last between 5 and 15 years, though material choice and patient habits can extend this range. Proper oral hygiene is necessary to prevent decay from developing at the margin where the crown meets the natural tooth structure.
This includes brushing with fluoride toothpaste twice daily and flossing around the crown’s base. Patients should avoid chewing on non-food items like ice or fingernails, as these habits can cause chipping or loosen the cemented crown. If a patient grinds their teeth at night, wearing a custom-fitted nightguard is recommended to protect the crown. Regular dental check-ups and professional cleanings every six months allow the dentist to monitor the crown’s integrity and the health of the surrounding gum tissue.