A temporary crown protects the reduced tooth structure (the abutment) while a permanent crown is fabricated. These provisional restorations maintain space between teeth, prevent gum tissue overgrowth, and restore basic aesthetics and chewing function. Because the crown is designed for easy removal, it is secured with a specialized, weaker cement. This intentional design, combined with chewing forces, means a temporary crown can become dislodged without warning.
The Limits of Toothpaste as a Temporary Adhesive
Toothpaste is a last-resort measure to re-seat a temporary crown, not a reliable adhesive. Its effectiveness is severely limited because it is not formulated to resist the harsh environment of the mouth. While the sticky consistency may initially allow the crown to be positioned, the resulting bond is fragile.
The primary mechanism of failure is that toothpaste is water-soluble. It rapidly breaks down upon contact with saliva, warm liquids, and the force of a typical bite. Adhesion is typically measured in minutes, lasting a maximum of a few hours only under ideal, non-chewing conditions. Any attempt to eat or drink beyond small sips of cool water will almost certainly dislodge the crown.
Why the Temporary Crown Must Be Replaced Immediately
Leaving the prepared tooth exposed carries immediate and serious dental risks beyond simple discomfort. The most common issue is extreme sensitivity, as the protective enamel layer has been removed, leaving the dentin vulnerable. This exposure transmits temperature changes directly to the pulp, resulting in sharp pain when consuming hot or cold items.
A more serious complication is the potential for tooth movement. The prepared tooth, lacking the structure of a full crown, can quickly shift or supra-erupt (move out of the socket). Even small movements prevent the permanent crown, which was precisely molded to the original space, from fitting correctly. Additionally, the exposed surface of the abutment is highly susceptible to bacterial colonization and decay.
Recommended Over-the-Counter Repair Kits
A superior option to toothpaste is an over-the-counter temporary dental cement kit, available at most pharmacies. These products are formulated specifically for oral use and provide a more stable, temporary bond. The kits often contain materials like zinc oxide-eugenol or calcium sulfate, which set hard when exposed to moisture.
Unlike toothpaste, these cements are water-resistant and create a sealing bond during the setting process. To use them, the inside of the temporary crown and the abutment tooth must be thoroughly cleaned and dried. Apply a small amount of cement inside the crown, place it back over the tooth, and gently hold it in place until the material sets. This provides a secure seal that can reliably last for several days until a professional appointment.
What to Do Until the Dental Appointment
The first action upon losing a temporary crown is to contact your dental office immediately to schedule an emergency re-cementation appointment. Do not delay, as the risks of leaving the abutment exposed increase quickly. If you must replace the crown yourself using toothpaste or an OTC kit, thoroughly clean the inside of the crown and the tooth preparation before application.
Once the crown is re-seated, strictly avoid chewing any food on that side of your mouth. When cleaning, brush the area gently, being careful not to dislodge the temporary crown. If the crown is swallowed, it will typically pass harmlessly through the digestive tract. However, you should still inform your dentist and continue with your scheduled re-cementation appointment.