Temporary dental fillings are made from a handful of materials designed to seal and protect a tooth for a limited time, typically a few weeks to a few months. The most common base ingredient is zinc oxide, which appears in nearly every type of temporary filling material. What varies is what’s mixed with it and how the material hardens.
Zinc Oxide Eugenol (ZOE)
The most traditional temporary filling combines zinc oxide powder with eugenol, a liquid extracted from clove oil. When mixed together, these two ingredients form a paste that gradually hardens into a solid seal. ZOE has been a staple in dentistry for decades because eugenol has a mild sedative effect on the nerve inside a tooth, which helps reduce sensitivity and pain after a procedure.
For basic short-term fillings, a dentist mixes unmodified ZOE to a putty-like consistency, sometimes adding a few cotton fibers for reinforcement. Setting speeds up when moisture is applied to the surface. A more durable version called IRM (Intermediate Restorative Material) adds polymers and magnesium oxide to the standard ZOE formula, making it stronger and better suited for fillings that need to last a bit longer or withstand more chewing force.
One drawback: eugenol can interfere with certain bonding agents used in permanent fillings. If your dentist plans to place a resin composite restoration later, they may choose a non-eugenol material instead. Eugenol can also trigger allergic reactions in some people, causing irritation of the gum tissue or, in rare cases, more serious symptoms. For those patients, glass ionomer cement is a common alternative.
Cavit and Pre-Mixed Materials
Cavit is a popular brand-name temporary filling material that comes ready to use straight from the tube. Its composition, based on the manufacturer’s data, is roughly 30 to 50 percent zinc oxide, with calcium sulfate, barium sulfate, talc, zinc sulfate, and a small amount of polymer (polyvinyl acetate) making up the rest. A plasticizer keeps the paste workable until it’s placed in the tooth.
What makes Cavit convenient is that it sets on contact with moisture in the mouth. Your saliva triggers the hardening process, so no mixing is required. This also means premature exposure to moisture (if the material gets wet before placement) can cause it to set too early. Dentists frequently use Cavit between root canal appointments because it’s fast, easy to place, and creates a reliable seal against bacteria.
Glass Ionomer Cement
Glass ionomer cement is made from a fluoride-containing glass powder (fluoro-aluminosilicate) mixed with a liquid solution of polyacrylic acid. When the powder and liquid combine, a chemical reaction bonds the material to the tooth structure. This is one of the few filling materials that chemically adheres to enamel and the layer beneath it, rather than just sitting in a cavity mechanically.
Glass ionomer also releases small amounts of fluoride over time, which can help protect the surrounding tooth from further decay. It’s softer than permanent filling materials, so it won’t hold up to heavy chewing indefinitely. But for temporary use, especially in patients who are sensitive to eugenol, it works well.
Why Dentists Use Temporary Fillings
A temporary filling isn’t a lesser version of a permanent one. It serves a specific purpose during treatment that’s still in progress. The most common scenario is root canal therapy. Since root canals often take more than one appointment to complete, the access hole drilled into the tooth needs to be sealed between visits. Without a proper temporary filling, bacteria from saliva can re-infect the canal and undo the work already done.
Temporary fillings also keep any medication placed inside the tooth from leaking out, prevent gum tissue from growing into the open cavity, protect weakened tooth structure from cracking under chewing forces, and maintain the shape of the cavity so the dentist has consistent reference points at the next visit. Outside of root canals, temporary fillings are used after pulp capping procedures, while waiting for a custom crown or inlay to be fabricated, or as an emergency measure to cover a broken tooth until a full appointment can be scheduled.
How Long They Last
Temporary fillings can hold up anywhere from a few weeks to a few months depending on the material, the size of the cavity, and where in the mouth the tooth is located. They’re not designed for long-term use. The materials are softer and less wear-resistant than permanent fillings, and they gradually break down. Leaving a temporary filling in place too long increases the risk of the seal failing, which can let bacteria back in and lead to reinfection or further decay.
Your dentist will tell you when to return for the permanent restoration. Sticking to that timeline matters more than how the filling feels. A temporary filling can seem perfectly fine while the seal underneath is slowly deteriorating.
Caring for a Temporary Filling
Most dentists recommend waiting until any numbness from anesthesia wears off before eating, so you don’t accidentally bite your tongue or cheek. For some materials, you may also need to avoid chewing on that side of your mouth for 24 hours to let the filling fully set.
Once you’re eating normally, steer clear of anything hard (ice, nuts, hard candy) or sticky (gum, toffee, peanut butter). These can crack or pull the filling out. Chew on the opposite side when possible. Brush gently around the filled tooth and continue flossing, but be careful not to snag the filling when pulling floss through. If the filling chips, cracks, or falls out before your next appointment, contact your dentist. An exposed cavity can quickly become reinfected.