Adults frequently require restorative dental work, and they can certainly receive “caps” on their teeth. Dental crowns, often referred to as caps, are a common and effective treatment used to repair and protect damaged teeth. This procedure restores a tooth’s original form, strength, and appearance. Crowns are a reliable method for preserving teeth that might otherwise need extraction, providing a durable solution for patients.
Defining Dental Crowns and Their Function
A dental crown is a custom-made, tooth-shaped covering that is permanently placed over the entire visible portion of a damaged tooth, sitting above the gum line. The primary purpose of this restoration is to encase the entire prepared tooth surface, restoring its original shape and size. By covering the tooth completely, a crown provides reinforcement, shielding the structure from the heavy forces of chewing.
Crowns differ from other common dental restorations like fillings and veneers. A dental filling repairs small areas of decay, whereas a crown encases the entire tooth. Veneers are thin, custom-made shells bonded only to the front surface of a tooth for cosmetic improvements, offering little structural protection compared to a crown.
Indications for Adult Dental Crowns
A dentist will recommend a crown when the underlying tooth structure is too compromised to be repaired by a simple filling or inlay. Crowns are utilized for several primary reasons:
- To protect a tooth following a root canal procedure, as the tooth often becomes brittle and requires full coverage to prevent fracture.
- To stabilize a cracked or fractured tooth, holding the parts together and preventing further damage.
- To restore teeth with decay too large for a durable filling.
- To return worn-down teeth (due to grinding or acid erosion) to their correct height and form.
- To serve as the final restoration placed on top of a dental implant.
- To cover discolored or misshapen teeth for cosmetic purposes.
Types of Crown Materials
The selection of crown material involves balancing aesthetics, strength, and the location of the tooth within the mouth. All-ceramic or all-porcelain crowns offer the best aesthetic outcome because they mimic the light-reflecting properties of natural enamel, making them ideal for visible front teeth. However, traditional porcelain can be more susceptible to chipping or fracture compared to metal-based options.
Metal alloy crowns, which may use gold, palladium, or base metals, are the most durable and resistant to wear and fracture, making them the material of choice for molars where chewing forces are highest. These crowns can also be made thinner, requiring less removal of the natural tooth structure, but their metallic color is their main aesthetic drawback.
Porcelain-fused-to-metal (PFM) crowns attempt to combine these benefits, providing a metal core for strength covered by a porcelain layer for a more natural look. A potential disadvantage of PFM is the possibility of a dark metal line becoming visible at the gum line over time as gums recede. Zirconia has become a popular modern material, offering a combination of strength comparable to metal with good aesthetics. Zirconia crowns are resistant to fracture and are biocompatible, making them a suitable option for both front and back teeth.
The Procedure and Longevity
The process for receiving a permanent crown typically involves two separate appointments spaced about two weeks apart. During the first visit, the dentist prepares the tooth by removing a portion of the outer enamel and dentin to create space for the crown material to fit over it. An impression or digital scan of the prepared tooth is then taken to send to a dental laboratory, which custom-fabricates the permanent crown. A temporary crown is placed over the tooth to protect it while the permanent one is being made.
The second appointment involves removing the temporary crown and permanently cementing the finished custom crown onto the prepared tooth structure. The longevity of a dental crown is typically between 5 to 15 years, though many can last longer with excellent care. The lifespan depends on the material chosen, the location in the mouth, and the patient’s oral hygiene habits. Proper maintenance involves daily brushing and flossing, especially around the crown margin, and avoiding habits like chewing on hard candies or ice to prevent chipping or loosening the restoration.