A dental crown is a cap placed over a damaged tooth to restore its shape, size, strength, and appearance. This restoration relies entirely on dental cement to create a secure seal and bond it to the underlying tooth structure. Once this cement bond fails, a loose crown will not tighten back up on its own because the adhesive material has deteriorated or washed out. Since the crown’s stability depends solely on this seal, professional intervention is required to re-establish the bond and prevent further damage to the exposed tooth.
Reasons a Dental Crown Becomes Loose
The most frequent cause for a crown becoming loose is the gradual breakdown of the dental cement that holds it in place. Over time, the constant forces from chewing and exposure to saliva can weaken the adhesive bond, causing the cement to wash out from the margin where the crown meets the tooth. This deterioration is a normal process, particularly for crowns that have been in place for many years, but it can be accelerated by habits like teeth grinding or clenching.
A more serious underlying issue is the development of tooth decay beneath the crown itself. Although the crown is not susceptible to decay, the natural tooth structure it covers remains vulnerable to bacteria and cavities at the margins. When decay progresses, it erodes the supporting tooth material, which changes the shape of the foundation and compromises the precise fit required to keep the crown secure.
Physical factors can also contribute to the dislodging of a crown, even a recently placed one. Biting down on hard foods, such as nuts or ice, or consuming sticky foods like caramel can exert strong pulling forces that break the cement seal. Additionally, trauma to the mouth from an accident or injury can apply sudden, excessive pressure, causing the crown to become loose or fall off completely.
Essential Immediate Steps to Take
If a crown is loose or has come off, contact your dental office immediately to schedule an appointment. If the crown is completely detached, carefully remove it from your mouth to avoid accidentally swallowing it. After gently rinsing the crown with water, store it safely in a clean container or plastic bag. The dentist may be able to re-cement the original restoration.
The exposed underlying tooth can be highly sensitive to temperature changes and pressure, so it is important to protect it until your appointment. Avoid chewing food on the side of the mouth with the affected tooth, and be gentle when brushing and flossing around the area. You can temporarily stabilize the crown if it is intact and the exposed tooth is not painful or damaged.
To temporarily re-seat the crown, you can purchase over-the-counter temporary dental cement from a pharmacy and follow the product’s instructions. A small amount of petroleum jelly or toothpaste can also be applied inside the crown to hold it in place for a few hours, but these are not secure replacements for dental cement. Never use household glues or adhesives, as these materials are toxic and can cause irreparable damage to the tooth and soft tissues.
Professional Treatment Options for Restoration
When you see the dentist, they will perform a thorough examination of both the crown and the underlying prepared tooth. If the crown is undamaged and the supporting tooth structure is intact and free of decay, the existing crown can often be cleaned and re-cemented using a professional-grade dental adhesive. This re-cementing process is the most straightforward resolution when cement failure is the sole cause of the loosening.
However, if an X-ray or visual inspection reveals that tooth decay has formed beneath the crown, the dentist must first remove the decay and rebuild the remaining tooth structure. This may involve placing a core buildup to create a stable foundation before any new restoration can be secured. If the decay is extensive or if the crown itself is fractured, chipped, or ill-fitting, a complete replacement is necessary.
In replacement scenarios, the dentist will take a new impression of the prepared tooth to have a custom crown fabricated in a laboratory, ensuring a precise fit to prevent future loosening. A temporary crown will be placed to protect the tooth and maintain proper spacing while the permanent restoration is being created. Addressing the underlying cause, whether it is decay or a poor fit, is necessary to ensure the longevity of the new crown.