A dental crown is a tooth-shaped cap placed over a damaged or weakened tooth to restore its shape, size, strength, and appearance. Crowns are a common solution for teeth with extensive decay, fractures, or those that have undergone root canal treatment. Understanding the longevity of dental crowns and when they might require attention is important for maintaining overall oral health.
Understanding Crown Lifespan
Dental crowns are durable, but not permanent. They typically last 5 to 15 years, with some lasting 20 years or more with proper care. Lifespan is influenced by material, location, and oral hygiene. For instance, gold crowns are known for exceptional durability, lasting 20 years or more. Porcelain-fused-to-metal (PFM) crowns typically last 5-15 years, while strong zirconia crowns often last 15-20 years.
Crowns on molars, which endure significant chewing forces, may wear faster than those on front teeth. Consistent oral hygiene, including brushing and flossing, helps prevent decay around the crown, extending its life. Lifestyle habits like teeth grinding (bruxism) or chewing on hard objects can also reduce a crown’s lifespan. Regular dental check-ups allow dentists to monitor the crown’s condition.
Common Reasons for Crown Replacement
Dental crowns may need replacement for various reasons, often stemming from issues with the crown itself or the underlying tooth structure.
Decay
Tooth decay developing beneath the crown, particularly at the margins where the crown meets the natural tooth, is a frequent cause for replacement. Neglected oral hygiene or a poorly fitting crown can create gaps, allowing bacteria to accumulate and weaken the tooth.
Physical Damage
Physical damage, such as chips, cracks, or fractures, is another common reason. This can result from biting hard foods, trauma, or daily chewing forces. While minor chips may be repaired, significant damage often requires full replacement.
Loose Crown
Over time, the dental cement bonding the crown to the tooth can degrade, causing the crown to become loose or fall off.
Underlying Tooth Issues
Issues with the underlying tooth, such as a fractured root or the need for a root canal after crown placement, can lead to crown failure. Inadequate tooth preparation or incorrect crown placement can also result in an uneven bite or discomfort, requiring adjustment or replacement.
Aesthetic Concerns
Aesthetic concerns like discoloration or a dark line appearing at the gum line, especially with porcelain-fused-to-metal crowns, sometimes prompt replacement.
Recognizing Signs Your Crown Needs Attention
Specific signs can indicate a failing dental crown or one requiring professional evaluation:
- Persistent pain or discomfort around the crowned tooth, especially when biting, chewing, or exposed to hot or cold temperatures. Increased sensitivity can also signal a compromised crown seal.
- Visible damage to the crown, such as cracks, chips, or significant wear. Minor imperfections can worsen and affect the crown’s protective function.
- A crown that feels loose, wobbly, or shifts when touched or chewed, indicating a weakened adhesive bond. This looseness can create spaces for bacteria, increasing decay or infection risk.
- Changes in your bite, where the crowned tooth feels “high” or misaligned, suggesting a shifting crown or fit issue.
- Gum issues around the crown, such as redness, swelling, bleeding, or recession. These can stem from a poorly fitting crown irritating tissue or bacterial accumulation due to an inadequate seal.
The Crown Replacement Process
When a dental crown requires replacement, the process generally involves several steps to ensure the new restoration fits properly and functions effectively. The dentist first examines the existing crown and underlying tooth, often with X-rays. After numbing the area, the old crown is carefully removed. Removal might involve a specialized tool to loosen the crown or, if necessary, cutting it to break the bond.
Once the old crown is off, the dentist cleans the underlying tooth, removing decay or compromised structure. The tooth is then re-prepared and reshaped to create an optimal foundation for the new crown. Impressions of the prepared tooth are taken, using traditional putty or digital scans, to ensure the new crown is custom-made. These impressions are sent to a dental laboratory for fabrication, a process typically taking a few weeks.
During this fabrication period, a temporary crown is placed to protect the prepared tooth and maintain position. Once the permanent crown is ready, the patient returns for a second appointment. The temporary crown is removed, and the new crown is checked for fit, bite, and aesthetics. Adjustments are made before the new crown is permanently bonded to the tooth with dental cement.
Implications of Not Replacing a Crown
Delaying the replacement of a failing dental crown can lead to a series of escalating oral health problems. Without a properly sealed crown, the underlying natural tooth is vulnerable. This increases the risk of decay beneath the compromised crown, as bacteria easily access the tooth structure. Rapid decay can reach the tooth’s pulp, necessitating a root canal or extraction.
An untreated failing crown can cause pain, sensitivity, and discomfort, especially when chewing or exposed to temperature changes. If decay or damage leads to infection, an abscess can form, a painful collection of pus that can spread to surrounding tissues and bone, causing swelling, fever, and requiring extensive treatments.
A loose or fractured crown can affect your bite, leading to uneven pressure and damage or excessive wear on other teeth. Jagged edges from a chipped or broken crown can also irritate or cut soft tissues of the mouth, such as the tongue or cheeks. Neglecting a failing crown can ultimately lead to tooth loss, requiring more complex and costly solutions like dental implants or bridges.