A temporary dental crown (provisional or interim restoration) is a protective cap placed over a prepared tooth while the final, permanent crown is custom-made in a dental laboratory. Its primary function is to shield the newly shaped tooth structure from the oral environment, preventing sensitivity and bacterial exposure. This temporary solution also maintains the correct spatial relationship between teeth, ensuring adjacent teeth do not shift and opposing teeth do not move into the open space. Furthermore, it allows the patient to maintain a natural appearance and normal function, such as speaking and chewing, during the waiting period.
Preparing the Tooth and Taking the Mold
The process begins with preparing the tooth that will receive the final restoration. A dental professional uses specialized burs to reduce the size of the existing tooth, shaping it into a smaller, tapered structure called an abutment. This reduction creates enough space for the crown material to fit without appearing bulky or interfering with the patient’s bite. Because the prepared tooth is highly vulnerable and sensitive, immediate placement of a provisional restoration is essential.
Before tooth reduction, an impression of the existing, unprepared tooth is taken using a putty material or a digital scanner. This pre-operative impression serves as the matrix, or template, for fabricating the temporary crown. Capturing the original contours ensures the temporary crown closely mimics the natural shape and size, which is important for comfort and aesthetics. The impression is used immediately after preparation to quickly form the provisional cap.
Materials and Methods for Crown Creation
Material selection balances adequate strength for chewing with ease of removal when the permanent crown is ready. Common materials include acrylic resins, particularly Polymethyl Methacrylate (PMMA), and composite resins, such as Bis-Acryl composite. Acrylic resins are durable and easy to polish but may have a higher shrinkage rate upon setting. Bis-Acryl composites are popular due to superior aesthetics, lower heat generation during setting, and less dimensional change, resulting in a better fit.
Temporary crowns are fabricated using two primary techniques: the direct method or the indirect method. The direct method is completed chairside, directly in the patient’s mouth, and is the most common approach for single-tooth restorations. The resin material is mixed and placed into the pre-operative matrix, which is seated over the prepared tooth. The material is allowed to set or cure before the matrix is removed, leaving the rough temporary crown in place.
The indirect method creates the crown outside the mouth, often by a technician using a model of the prepared tooth. This involves taking an impression of the prepared tooth and pouring a stone model, where the provisional crown is sculpted and cured. This approach is favored in complex cases or when superior marginal fit and aesthetics are desired, allowing for precise control. After curing, the dental professional trims and polishes the crown to ensure smooth margins and a comfortable bite before cementation.
Securing the Crown and Maintenance
The temporary crown is secured onto the prepared tooth using a specific temporary dental cement. This cement provides adequate retention for normal function but is intentionally weaker than permanent cement. The weaker bond ensures the crown can be easily and quickly removed without damaging the underlying tooth when the patient returns for the final restoration. After cementation, the dentist removes excess cement from the margins and checks the patient’s bite for final adjustments.
Patient maintenance is essential for keeping the temporary crown intact for the required two to three weeks. Patients must avoid chewing hard or sticky foods, such as caramel, gum, or nuts, which could crack the material or dislodge the crown. When eating, it is recommended to shift the bulk of chewing to the side opposite the temporary restoration to minimize stress.
Oral hygiene should continue normally using a soft-bristled toothbrush. Flossing requires a modified technique to prevent dislodgement. Instead of pulling the floss up and out, which could snag the crown’s margin, the floss should be gently slid out from the side between the teeth.
What to Do If the Crown Falls Off
A temporary crown may occasionally become loose or fall off due to cement washout, heavy chewing, or impact. If this occurs, retrieve the crown and contact the dental office immediately. The prepared tooth is exposed, making it highly susceptible to sensitivity, pain, and unwanted shifting of adjacent teeth. Both the exposed tooth and the inside of the crown should be cleaned gently to remove debris or old cement.
If the dental office cannot see the patient immediately, temporary re-seating may be necessary to protect the tooth. Over-the-counter temporary dental cement kits provide the most secure temporary hold. Alternatively, denture adhesive or petroleum jelly can be used as a stopgap measure until the next business day. When re-seating, place a small amount of adhesive inside the crown and carefully press it onto the tooth in the correct orientation. Any home re-seating is a short-term fix, and the crown must be professionally re-cemented as soon as possible to prevent complications.