A temporary crown is a molded, protective cap placed over a tooth that has been prepared for a permanent restoration. Its primary role is to shield the newly shaped, sensitive tooth structure from bacteria and temperature changes until the custom-made permanent crown is ready. The temporary crown also ensures that the surrounding teeth do not shift, which is crucial for the final crown to fit correctly. While designed to be functional for a short period, temporary crowns are held in place with a deliberately weak adhesive, making their dislodgement a common issue.
Primary Reasons for Dislodgement
The main reasons a temporary crown fails stem from mechanical forces, material properties, and the underlying tooth preparation. Temporary dental cement, often a zinc oxide compound, is intentionally designed to have low bond strength. This weak adhesion allows the dentist to easily remove the temporary crown without damaging the underlying tooth when placing the permanent one.
The bite force exerted when chewing is a significant mechanical factor that can cause failure. Uneven pressure on the crown, known as occlusal interference, acts like a lever, creating forces that pull the crown away from the tooth. This is especially true if the temporary crown is slightly too “high,” causing it to absorb excessive force whenever the jaw closes. Parafunctional habits, such as grinding or clenching the teeth (bruxism), subject the temporary cement to constant, excessive stress, rapidly weakening the bond.
Retention is highly dependent on the preparation of the underlying tooth structure. If the prepared tooth is too short or has walls are not parallel, there is insufficient surface area for the cement to grip effectively. The temporary crown is made from less durable materials like acrylic or composite resin, which are more susceptible to wear than the final restoration. Exposure of the temporary cement to saliva and temperature fluctuations can also lead to gradual material degradation, reducing its limited holding power over time.
Immediate Steps When the Crown Falls Out
If the temporary crown comes off, contact the dental office immediately for guidance and to schedule a recementation appointment. The exposed tooth is sensitive and vulnerable to shifting, which can compromise the fit of the final crown. While waiting, gently retrieve the crown and clean both the inside of the crown and the prepared tooth structure with water and a soft toothbrush.
You can attempt to re-seat the crown yourself, but only if it slides easily into the correct position, like a puzzle piece. Never force the crown back onto the tooth, as this risks damaging the prepared tooth or the crown itself. If the crown fits, you may use an approved over-the-counter temporary dental cement kit from a pharmacy to hold it in place.
If commercial cement is unavailable, a tiny amount of petroleum jelly or toothpaste can act as a short-term adhesive to maintain the crown’s position. Apply a minimal amount inside the crown, seat it, and gently bite down to secure it, wiping away any excess material. This technique is only a holding measure to prevent the tooth from shifting until the dentist can properly recement it.
Eating and Care Guidelines to Prevent Loosening
Maintaining the temporary crown requires modifying eating and oral hygiene habits to minimize stress on the cement bond. Avoid chewing directly on the side of the mouth where the temporary restoration is located, directing all chewing forces to the opposite side. Specific sticky foods, like caramel, taffy, or chewing gum, must be avoided as they can mechanically pull the crown off the tooth.
Hard or brittle foods, such as nuts, ice, or crusty breads, should also be avoided, as the sudden, concentrated force can fracture the temporary material or break the cement seal. Brushing should be performed gently around the temporary crown using soft bristles and a non-abrasive technique.
Flossing requires a specific modification to prevent dislodgement. After sliding the floss down and cleaning the sides of the temporary crown, do not pull the floss back up out of the contact point between the teeth. Instead, release one end of the floss and gently pull the entire strand sideways, out from under the contact point. This technique prevents the upward snapping motion that is the most common cause of pulling the temporary crown loose.