A dental crown is a custom-made cap used to restore a damaged or weakened tooth, but the process of creating the final restoration in a laboratory takes time. A temporary crown is a provisional restoration used during this waiting period, typically a few weeks. Its purpose is to protect the underlying prepared tooth structure, prevent the tooth from shifting, and shield the soft gum tissues from irritation. This interim cover also helps maintain the function and appearance of the tooth until the durable, permanent crown is ready for placement.
Visual Description and Composition
A temporary crown is designed to broadly mimic the shape of the original tooth it is covering, ensuring it generally fits within the patient’s bite. While it restores the overall contour of the tooth, its appearance is notably different from the final, high-quality restoration. The color is often selected from a limited range of uniform shades, sometimes appearing slightly dull or opaque compared to the surrounding natural teeth. This is because the temporary material is not designed for the complex, nuanced light reflection and color matching achieved with permanent porcelain.
The most common materials used for temporary crowns are acrylic resins or bis-acryl composite resins. These materials are chosen because they can be easily fabricated chairside by the dentist and are simple to adjust or remove when the time comes. Bis-acryl resins, which are a hybrid between acrylic and dental composite, are frequently used due to their acceptable aesthetics and relative ease of manipulation. However, these materials are inherently softer and less color-stable than the porcelain or metal alloys used for the final crown.
Structural Differences from the Final Crown
The fundamental difference between the temporary crown and its final counterpart lies in its intended lifespan and durability. Temporary crowns are built to last only a few weeks and are made from relatively weak polymers that are prone to chipping or cracking under heavy chewing forces. The fit of a temporary crown is also not as precise as the permanent version, which is custom-fabricated from a detailed impression of the prepared tooth. The margins, where the crown meets the gum line, may not be perfectly sealed, which is acceptable for a short-term solution.
The thickness and strength of the temporary material are lower than those of the permanent restoration, which may be constructed from high-strength ceramics like zirconia or porcelain fused to metal. These weaker materials are not intended to withstand the constant pressures of mastication over years, only for the transitional period. This difference in structural integrity is why dentists advise patients to avoid chewing hard or sticky foods on the side of the temporary crown.
Managing the Temporary Status
The temporary crown is secured with a non-permanent dental adhesive. This temporary cement is intentionally designed to be weak enough for the dentist to easily remove the crown without damaging the prepared tooth. This weak attachment means the crown is susceptible to dislodgement if exposed to excessive force, such as from sticky candies or hard foods. If the temporary crown does come loose, the underlying prepared tooth can become highly sensitive to temperature changes and air exposure.
If the crown becomes dislodged, the unprotected, prepared tooth is vulnerable to bacterial contamination and movement, which could compromise the fit of the permanent crown. If this occurs, a patient must contact the dental office without delay for re-cementation or replacement. The temporary cement balances the need for short-term protection with the requirement for non-destructive removal at the final appointment.