Temporary crowns are significantly weaker than permanent ones, but they’re strong enough to handle light everyday chewing for the two to three weeks you’ll typically wear one. Most temporary crown materials can withstand somewhere between 300 and 600 newtons of biting force when properly made, which covers normal chewing but leaves little margin for hard or sticky foods. Understanding exactly where these crowns fall short helps you protect them until your permanent crown is ready.
What Temporary Crowns Are Made Of
Most temporary crowns are fabricated from one of two types of dental resin: polymethyl methacrylate (PMMA) or bis-acryl composite. Both are plastic-based materials that cure quickly in the dental office, which is why your dentist can shape and place one in a single visit. Newer 3D-printed resin crowns are also becoming common, with flexural strength values in the range of 60 to 90 megapascals, roughly comparable to traditional PMMA and bis-acryl materials.
For context, flexural strength measures how much bending force a material can take before it snaps. Standard temporary crown materials score between about 11 and 24 MPa in basic chemical-curing formulations, while dual-curing systems can reach over 80 MPa. That’s a wide range depending on the specific product your dentist uses, but all of these numbers sit well below the strength of permanent crown materials like zirconia or porcelain-fused-to-metal.
How They Compare to Permanent Crowns
The gap between temporary and permanent crowns is substantial. Permanent zirconia crowns can resist fracture forces of roughly 575 newtons or more, while some newer resin-based permanent crowns exceed 1,200 newtons. Temporary crowns, by contrast, are engineered to survive the maximum normal biting force in the molar region (roughly 300 to 600 newtons) but without much safety margin. A permanent crown is built to last a decade or more under daily grinding and chewing. A temporary crown only needs to survive a few weeks.
This difference isn’t a design flaw. Temporary crowns are intentionally made from softer, weaker material because your dentist needs to remove them easily when the permanent crown arrives. If a temporary were bonded and built like a permanent crown, getting it off could damage the prepared tooth underneath.
Why the Cement Matters Too
The crown itself is only half the equation. Temporary crowns are held in place with weak cement on purpose. Temporary dental cements produce bond strengths in the range of about 2.5 to 7 MPa, depending on the type. That’s enough to keep the crown seated during normal function but weak enough that your dentist can pop it off without special tools.
This intentionally low bond strength is the main reason temporary crowns come loose. The material might survive a bite force that the cement cannot. Sticky foods like caramel or taffy can grab the crown and pull it right off the tooth because the adhesive holding it down simply isn’t that strong. The crown didn’t break; the seal gave way.
What Actually Causes Them to Fail
Temporary crowns fail in two main ways: they crack, or they come loose. Cracking happens most often from hard, crunchy foods. Biting down on ice, nuts, hard candy, or a popcorn kernel concentrates force on a small area of the crown, and the resin can chip or fracture. Sideways forces are especially problematic. Your teeth naturally shift laterally when you chew, and these off-axis loads stress the thinnest parts of the crown where the material is most vulnerable.
Dislodgement is usually caused by sticky or chewy foods. Gummy candy, dried fruit, crusty bread, and even chewing gum can grip the crown surface and tug it free from the temporary cement. Once a crown loosens even slightly, saliva seeps underneath and weakens the remaining bond, making it more likely to come off completely.
Wall thickness also plays a role. Temporary crowns need a minimum material thickness of about 0.8 millimeters to withstand normal chewing forces. If the crown is thinner than that in any spot, perhaps due to the shape of the prepared tooth or how the crown was fabricated, that thin area becomes a weak point where fractures start.
What You Can and Can’t Eat
You can eat most normal foods with a temporary crown, but you’ll want to shift your chewing to the opposite side of your mouth when possible and avoid a few categories:
- Hard foods: Raw carrots, nuts, ice, hard pretzels, and crusty bread rolls can chip or crack the resin.
- Sticky foods: Caramel, taffy, gummy candy, and chewing gum can pull the crown off entirely.
- Chewy foods: Tough steak, beef jerky, and bagels put sustained stress on the bond between crown and tooth.
- Extreme temperatures: Very hot or cold foods won’t break the crown, but the prepared tooth underneath is often sensitive, and temperature extremes can cause sharp discomfort.
Softer foods like pasta, scrambled eggs, cooked vegetables, and fish are all fine. You can chew on the temporary crown side for lighter bites. Just avoid concentrating heavy force there.
How Long They’re Designed to Last
Temporary crowns are designed to function for two to three weeks, which is the typical turnaround time for a dental lab to fabricate your permanent crown. Some situations require wearing a temporary for longer, such as when additional dental work is needed before the final crown can be placed. In those cases, your dentist may use a stronger temporary material or recement the crown partway through.
The longer you wear a temporary crown, the greater the chance of failure. The cement gradually breaks down from saliva exposure and chewing forces. The resin material itself can develop micro-cracks from repeated stress that eventually connect into a visible fracture. If your permanent crown appointment gets delayed, let your dentist know so they can check the temporary and recement it if needed.
If Your Temporary Crown Comes Off
A loose or dislodged temporary crown is one of the most common dental complaints, and it’s usually not an emergency. If the crown pops off intact, you can often slide it back over the tooth as a protective cover until you can get to your dentist. Some people use a small dab of denture adhesive or over-the-counter temporary dental cement (available at most pharmacies) to hold it in place for a day or two.
The exposed tooth underneath is often sensitive to air, temperature, and pressure because the outer enamel has been filed down during the preparation process. Keeping the crown on, even loosely, helps shield the tooth and prevents the surrounding teeth from shifting slightly into the gap, which could affect how well your permanent crown fits.