Temporary crowns are most commonly made from one of two plastic resins: polymethyl methacrylate (PMMA) or bis-acryl composite. Which one you get depends on your dentist’s preference, the location of the tooth, and how long you’ll need to wear it. Pre-formed options made from polycarbonate or stainless steel are also used in certain situations, and newer 3D-printed resins are becoming more common.
The Two Main Resin Types
PMMA is the older of the two materials. It’s an acrylic plastic, essentially the same family of material used in dentures. Your dentist mixes a liquid and powder that harden through a chemical reaction, which generates noticeable heat. That heat can be uncomfortable on a freshly prepared tooth, so dentists often remove the crown during setting and let it cure outside the mouth. PMMA is durable and holds its color reasonably well over time, but it releases residual chemical monomer during setting, which can irritate the nerve in a living tooth.
Bis-acryl composite is the more popular choice today. It comes pre-loaded in a double-barreled syringe and mixes automatically as it’s dispensed, making it faster and easier to use chairside. The material contains about 40% inorganic filler particles by weight, similar to tooth-colored filling material. That filler content gives it better strength, less shrinkage as it hardens, and a more natural appearance than plain acrylic. It also produces significantly less heat during setting, which is gentler on sensitive teeth. The tradeoff is that bis-acryl absorbs more water than PMMA, which can cause slight color changes if you’re wearing it for an extended period.
Pre-Formed Crowns
Not every temporary crown is custom-shaped in the office. For front teeth and premolars, dentists sometimes use pre-formed polycarbonate shells. These are made from polycarbonate resin reinforced with microglass fibers for added strength. They come in standard tooth sizes and shades, and the dentist trims and adjusts them to fit your tooth, then fills them with a small amount of resin or cement. They can be crimped and contoured much like a metal crown, making them relatively easy to adapt to the margins of your tooth.
For back teeth, especially in children, pre-formed stainless steel crowns are a common choice. These are silver-colored metal shells that sacrifice appearance for durability. They handle chewing forces well and are particularly useful when the temporary needs to withstand heavy biting pressure or when aesthetics aren’t a priority.
CAD/CAM and 3D-Printed Options
Some dental offices now mill temporary crowns from solid blocks of resin or composite using a computer-controlled milling machine. Because these blocks are manufactured under controlled conditions, they tend to be denser and stronger than crowns shaped by hand at the chairside. The result is a temporary that fits more precisely and resists fracture better than a hand-formed one.
3D-printed temporary crowns use light-cured resins built up layer by layer. The technology is newer, and the mechanical properties of printed resins vary widely between products. Printed temporaries for short-term use typically don’t contain the same level of filler particles found in permanent printed restorations, so they’re not as strong. Still, for a crown you’ll wear for a few weeks, they perform well and can be produced quickly from a digital scan of your mouth.
How the Cement Matters Too
The material of the crown itself is only half the story. The cement holding it in place is deliberately weak, designed to let your dentist pop the temporary off without damaging your tooth when the permanent crown is ready. Most temporary cements are based on zinc oxide, and they come in two main varieties: those containing eugenol (a compound derived from clove oil) and those without it.
Eugenol-based cements have a mild numbing effect that can help with sensitivity on a living tooth. However, eugenol interferes with the hardening of resin-based materials. It destroys the free radicals that kick off the curing process, leaving the surface soft and poorly bonded. If your permanent crown will be cemented with a resin-based adhesive, residual eugenol on the tooth can significantly reduce bond strength. For this reason, many dentists now default to eugenol-free temporary cements, especially when planning bonded ceramic or porcelain restorations.
How Long These Materials Last
Temporary crown materials are designed for short-term use, typically 3 days to 3 weeks. That window matches the time most dental labs need to fabricate a permanent crown. The materials hold up well within that range, but they begin to break down beyond it. The cement gradually dissolves from saliva exposure, loosening the crown and allowing bacteria to reach the prepared tooth underneath. Gum tissue around a poorly sealed temporary can become inflamed, and in some cases, neighboring teeth may shift slightly if the temporary’s fit degrades enough.
If circumstances delay your permanent crown (insurance issues, scheduling, or lab backlogs), your dentist can re-cement or remake the temporary. But wearing the same one for two months or longer without any maintenance increases the risk of decay on the prepared tooth and gum infection around the margins.
Living With a Temporary Crown
Regardless of the material, temporary crowns are softer and more brittle than permanent ones. Avoid hard foods like nuts, hard candy, and raw vegetables on that side. Sticky foods like gum, caramel, and taffy can grab the crown and pull it loose. Tough, chewy foods like steak put lateral forces on the crown that the weak cement can’t always resist.
Temperature matters as well. Very hot or cold foods and drinks can cause discomfort if any nerve endings are exposed beneath the temporary, and extreme temperatures can weaken the cement bond. Chewing on the opposite side when possible and cutting food into smaller pieces reduces the stress on the temporary considerably. If the crown does come off, save it. Your dentist can usually clean it and re-cement it in a short appointment, which is far easier than making a new one from scratch.