A dental crown is a custom-fitted cap placed over a damaged or weakened tooth, designed to restore its shape, size, strength, and appearance. While crowns are durable restorations meant to last for years, they can occasionally become loose and detach from the underlying tooth. This event can be alarming, but it is a relatively common occurrence that dentists are prepared to address. Understanding the reasons for this failure and knowing the correct steps to take can protect your tooth and ensure a quick resolution.
Common Reasons Why Crowns Detach
The most frequent cause of crown detachment is the failure of the dental cement used to bond it to the tooth structure. Over time, this adhesive degrades or “washes out” due to saliva and the mechanical forces of chewing, weakening the seal. Since the cement bond naturally decreases over many years, older crowns are more prone to coming loose.
Underlying tooth decay compromises the crown’s foundation. Bacteria can penetrate small gaps at the margin, leading to new decay in the remaining tooth structure. As the supporting tooth material is lost, the crown no longer has sufficient structure to grip and falls off. This decay often goes unnoticed until the crown fails.
Mechanical stress from bite issues or habits also places excessive force on the restoration, leading to dislodgement. Bruxism, or habitual teeth grinding and clenching, subjects crowns to forces far greater than normal chewing, which can fracture the crown or hasten the breakdown of the cement. Biting on hard objects like ice or using teeth as tools can also create sudden, high-impact trauma that dislodges the cap. Additionally, a poorly fitted crown, perhaps due to insufficient tooth preparation or an inaccurate impression, may never achieve a strong, long-lasting bond.
Immediate Steps After a Crown Falls Out
The first action is to retrieve the crown and keep it in a safe, clean container to prevent loss or damage. Gently rinse the crown with warm water to clean off any debris or old cement, but avoid scrubbing aggressively. The exposed tooth underneath may feel very sensitive to air or temperature changes because the protective layers are now uncovered.
Contact your dental office immediately to schedule an appointment, explaining that your crown has come off. While waiting, you must protect the exposed tooth and surrounding soft tissues. If the remaining tooth has sharp edges that could irritate your tongue or cheek, cover them with dental wax, which is available at most pharmacies.
If your dentist advises a temporary fix, you can use over-the-counter temporary dental cement, denture adhesive, or petroleum jelly inside the crown to re-seat it. Ensure the crown is positioned correctly before biting down gently to set it. Never use household glues, as they are toxic and prevent proper re-cementation. Avoid chewing on the side of your mouth where the crown is missing, and stick to soft foods.
Professional Treatment Options for Reattachment
When you see your dentist, the first step is a thorough assessment of both the fallen crown and the underlying tooth structure. The dentist will examine the tooth for signs of decay, fracture, or damage, often utilizing an X-ray to check the integrity of the tooth and the fit of the crown. This evaluation determines whether the existing crown can be reused.
If the crown is intact and the remaining tooth is healthy, the dentist can clean the old cement from both surfaces and professionally re-cement the crown using a strong dental adhesive. If the crown is fractured, or if the underlying tooth has sustained significant decay or structural damage, re-cementing may not be possible. In these cases, a new crown must be fabricated to ensure a proper seal and fit.
If extensive decay caused the crown to fail, the dentist will first remove all decayed tissue. This may necessitate additional restorative work, such as a core buildup to create structure for the new crown, or potentially a root canal if the decay reached the nerve. The goal is to restore the tooth’s health and provide a secure foundation before placing a new permanent restoration.
Preventing Future Crown Loss
Maintaining consistent oral hygiene is the primary defense against crown detachment caused by decay. Brushing twice daily with fluoride toothpaste and flossing daily prevents plaque accumulation, especially around the crown margin. Using an interdental brush can be helpful for cleaning the area where the gum meets the crown.
Dietary modifications are also effective in protecting the crown’s bond. Avoid hard, crunchy, or sticky foods like hard candies, nuts, caramel, and chewing gum, as these can exert pulling forces that loosen the cement or damage the crown material. Chewing on the side of the mouth opposite the crowned tooth, especially when consuming tougher foods, can reduce mechanical stress.
For individuals who experience bruxism, a custom-fitted night guard is a recommended preventative measure. This device cushions the intense forces generated by grinding and clenching, protecting the crown and the surrounding tooth structure from excessive wear and fracture. Regular dental check-ups and professional cleanings allow the dentist to monitor the crown’s integrity, assess the cement seal, and detect early signs of decay or wear before they lead to failure.