A dental crown is a custom-made cap placed over a damaged or weakened tooth, serving as a protective shield to restore its shape, size, and function. While crowns are designed for durability, they are not impervious to damage and can indeed crack. Cracking exposes the underlying natural tooth structure and can lead to discomfort. Understanding the causes, recognizing the signs, and addressing a crack promptly are necessary to safeguard oral health, as the crown’s longevity depends heavily on the materials used and the forces it withstands daily.
The Mechanics of Cracking Dental Crowns
Dental crowns crack due to material limitations combined with excessive physical stress applied over time. Crowns are crafted from various materials, and their susceptibility to fracture differs. Porcelain, while aesthetically superior, is brittle and more prone to cracking from sharp impacts or concentrated force compared to other options.
Materials like zirconia and metal alloys offer greater fracture resistance and strength. Zirconia has crystal properties that make it highly resistant to cracking, often requiring minimal thickness for stability. However, even the strongest crowns can fail under extreme conditions, such as severe trauma or chronic habits like bruxism (teeth grinding or clenching).
Excessive biting force from chewing very hard foods, like ice or hard candies, can exceed the material’s strength limit, leading to fracture. Temperature fluctuations can also contribute to cracking, particularly in porcelain-fused-to-metal (PFM) crowns, where mismatched expansion and contraction rates between the layers introduce stress. Additionally, a poorly designed or inadequately thick crown may concentrate stress, making it structurally weaker and more likely to crack under normal chewing pressure.
Recognizing the Signs of a Cracked Crown
A cracked crown can manifest through sensory and visual cues. One telling sign is a sudden, sharp pain when biting down or chewing, which indicates pressure is reaching the vulnerable tooth beneath the crown. This discomfort often occurs inconsistently, only when pressure is applied at a specific angle or spot.
Increased sensitivity to extreme temperatures, such as hot coffee or cold ice cream, is another common symptom. The crack may expose the underlying tooth structure, allowing temperature changes to irritate the dental pulp. Visually, a patient might notice a visible hairline fracture, a chip on the crown’s edge, or a rough spot that the tongue catches.
The crown may feel slightly loose or unstable, or the gum tissue around the tooth may become inflamed, red, or tender as bacteria enter the space created by the crack. A crack can be microscopic or located beneath the gum line, making it undetectable without a professional dental examination and diagnostic tools.
Immediate Steps and Professional Treatment Options
If you suspect your crown is cracked, the immediate priority is to contact your dental office to schedule an appointment. Until you can see a dentist, take steps to prevent further damage and manage discomfort. Avoid chewing food on the affected side to minimize pressure on the damaged restoration and the exposed tooth.
If the crack has created a sharp edge that irritates your cheek or tongue, temporarily cover it with a small amount of dental wax. Over-the-counter pain relievers, such as non-steroidal anti-inflammatory drugs, can help manage sensitivity or pain until your visit. Gently rinsing your mouth with warm water can also help clear debris from the area.
Once at the dentist, professional treatment depends on the extent of the damage. If the crack is minor, the dentist may repair it using a tooth-colored composite resin, a process known as dental bonding. However, if the crack compromises the crown’s structural integrity or affects the underlying tooth, a complete crown replacement is necessary. Delaying treatment risks allowing bacteria to reach the underlying tooth, causing decay, infection, or further fracturing of the natural tooth structure, which could necessitate a root canal or extraction.
Preventing Future Crown Damage
Protecting your crown involves modifying habits and adopting a preventative care routine. Being mindful of your diet and avoiding items that exert excessive force is key. This includes not chewing on hard foods like ice, popcorn kernels, or hard candies, which can easily create stress fractures in the crown material.
If you struggle with bruxism (teeth grinding), wearing a custom-fitted nightguard while sleeping helps absorb intense nocturnal biting forces. This protective appliance reduces the pressure placed on your crowns and natural teeth. Maintaining excellent oral hygiene, including brushing twice daily and flossing around the crown, is also important to prevent decay from forming underneath, which can weaken the restoration over time. Regular dental check-ups allow your dentist to monitor the crown for early signs of wear, addressing minor issues before they develop into major problems.