Temporary dental cement is a specialized adhesive used in multi-step restorative dentistry, designed for short-term use rather than permanent fixation. Its purpose is to secure a prepared tooth structure between initial treatment and the placement of a final restoration. The material acts as a protective shield, sealing the exposed dentin and pulp against contamination, temperature changes, and sensitivity. This temporary hold maintains the integrity of the prepared tooth and prevents shifting of adjacent teeth before the permanent appliance is ready.
Primary Role in Holding Provisional Restorations
The most frequent application of temporary cement is to retain a provisional restoration, such as a temporary crown, bridge, or veneer. These provisional appliances are fabricated immediately after the natural tooth is prepared to accommodate the final restoration. The cement secures this interim appliance, ensuring the patient can chew and speak comfortably while the custom-made permanent piece is manufactured in a dental laboratory.
The cement must strike a careful balance, providing enough retention to prevent dislodging during normal function like eating and brushing. However, its bond strength must remain low enough for the dentist to easily remove the temporary appliance without damaging the underlying tooth structure. This interim period typically lasts for a few weeks, allowing the laboratory sufficient time to craft the final restoration. Maintaining the position of the prepared tooth and surrounding gum tissue is paramount for the successful fit of the permanent appliance.
Temporary Use for Protection and Diagnostics
Temporary cements are utilized for therapeutic and diagnostic purposes beyond holding provisional appliances. One common non-retention use is as a temporary filling material, sealing a deep cavity preparation or a root canal access opening between appointments. This application provides a hermetic seal against the oral environment, protecting the tooth’s innermost tissues from saliva and microbes.
Sedative and Diagnostic Uses
Certain formulations, like those containing zinc oxide eugenol (ZOE), are selected for their sedative qualities on the dental pulp. Eugenol, derived from clove oil, can help reduce a patient’s hypersensitivity following an extensive preparation before the final restoration is placed. Dentists also use temporary cement to secure a final restoration for a short trial period. This allows assessment of the tissue response or the patient’s comfort before committing to permanent cementation.
Material Differences and Removal Process
Temporary cements are chemically engineered to possess significantly lower bond strength compared to permanent counterparts, which are designed for decades of durability. This difference is achieved by formulating the materials to have limited chemical adhesion, relying instead on mechanical retention within the restoration and the prepared tooth surface. The choice of temporary cement is dictated by its compatibility with the material used for the final permanent cementation.
ZOE vs. Non-Eugenol Cements
Zinc Oxide Eugenol (ZOE) cements are known for their soothing effect on the pulp. However, the eugenol component can interfere with the setting and bonding of resin-based permanent cements. Non-eugenol temporary cements, which replace eugenol with organic acids, are preferred when the final restoration will be bonded with a resin-based adhesive. These variants ensure no residue is left behind that could compromise the strength or integrity of the permanent bond.
Removal Process
The removal process is straightforward and designed to be atraumatic to the tooth surface. After the provisional restoration is gently dislodged, the dentist meticulously scrapes and cleans the prepared tooth to ensure every remnant of the temporary cement is removed. Residual material, especially from ZOE cements, can inhibit the chemical reaction of the permanent cement, leading to failure of the final restoration. Temporary cements are formulated to remain stable for about two to three weeks, and they are easily removed with minimal force.