Dentists use several types of cement for crowns, and the choice depends on the crown material, how much natural tooth structure remains, and whether the crown is temporary or permanent. The main categories are resin-based cements, glass ionomer cements, resin-modified glass ionomer cements, and zinc phosphate cement. Each works differently and has trade-offs in strength, sensitivity, and long-term performance.
Temporary vs. Permanent Cement
If you’re getting a crown, you’ll likely encounter two rounds of cementation. While your permanent crown is being made (usually one to two weeks), your dentist places a temporary crown using a weak cement made from zinc oxide mixed with eugenol, rosins, or pine gums. This cement is intentionally easy to break loose so the temporary crown can be removed without damaging your tooth. It holds well enough for eating soft foods, but it’s not meant to last.
Permanent cement is a different story. It’s designed to keep your crown in place for years, ideally a decade or more. The type your dentist chooses depends largely on what your crown is made of.
Resin-Based Cement
Resin cement is the strongest option and the go-to choice for most modern crown materials, especially all-ceramic and zirconia crowns. It works by forming a micro-mechanical bond: acidic components in the cement react with calcium in your tooth enamel and dentin, while the resin also bonds chemically to the crown material itself. This creates a tight seal at both surfaces.
For zirconia crowns specifically, resin cement is the standard recommendation across dental research. Dentists often combine it with a chemical primer containing a bonding agent that significantly improves how well the cement grips the zirconia surface. Without that surface treatment, zirconia’s smooth, non-porous structure makes bonding more difficult.
Resin cements come in several varieties. Some require the dentist to etch and prime your tooth first (a multi-step process), while self-adhesive resin cements simplify things by combining those steps into one. Self-adhesive versions are popular for their convenience, though they may produce a slightly weaker bond to tooth structure compared to the multi-step approach.
One downside: resin cements can shrink slightly as they harden (a process called polymerization), which sometimes creates tiny gaps at the margins. These gaps can occasionally cause sensitivity in the days after cementation, particularly if the tooth underneath is still alive.
Glass Ionomer Cement
Glass ionomer cement takes a completely different approach. Instead of forming a resin bond, it uses an acid-base reaction. Polyacrylic acid in the cement forms an ionic bond with calcium in your tooth’s enamel and dentin, creating a chemical attachment without the need for etching or priming.
The standout feature of glass ionomer is fluoride release. These cements continuously release small amounts of fluoride into the surrounding tooth structure, which helps protect against decay at the margins where the crown meets the tooth. The amount of fluoride released varies between products, but this anticavity benefit is a real advantage for patients who are prone to cavities.
The trade-off is strength. Glass ionomer cements are weaker than resin cements, making them less ideal for crowns that take heavy biting forces (like molars with minimal remaining tooth structure). They also have a low pH when first mixed, meaning they’re somewhat acidic at the moment of placement. This acidity can irritate the nerve inside a living tooth and cause temporary sensitivity.
Resin-Modified Glass Ionomer Cement
Resin-modified glass ionomer (RMGI) splits the difference between pure glass ionomer and resin cement. It keeps the fluoride-releasing properties and chemical bonding of glass ionomer while adding resin components for better strength and lower solubility. It’s also more forgiving of moisture during placement, which matters because keeping a tooth perfectly dry during cementation can be challenging, especially for crowns placed near the gumline.
RMGI is a common choice for metal and porcelain-fused-to-metal crowns, where the cement doesn’t need to be invisible (resin cements come in more shade options for all-ceramic crowns where appearance matters). It’s also popular for patients at higher decay risk because of that fluoride benefit. The fluoride release from RMGI tends to be lower than conventional glass ionomer, but it still offers measurable protection.
Zinc Phosphate Cement
Zinc phosphate is the oldest dental cement still in use, with over a century of clinical history. It holds crowns in place through mechanical retention rather than chemical bonding, meaning it relies on the crown fitting tightly over the tooth rather than actually adhering to it. This makes the shape and preparation of the tooth especially important when zinc phosphate is used.
Despite newer options, zinc phosphate remains popular with many clinicians because of its long track record and predictable behavior. It mixes easily, sets at a consistent rate, and has well-understood properties. It doesn’t release fluoride or bond chemically to tooth structure, but for well-fitting metal or porcelain-fused-to-metal crowns on teeth with good retention, it performs reliably for years.
How Crown Material Affects Cement Choice
Your dentist doesn’t pick cement in isolation. The crown material narrows the options considerably.
- Zirconia crowns perform best with resin cement, ideally paired with a chemical bonding agent applied to the crown’s inner surface before cementation.
- All-ceramic crowns (like lithium disilicate) also call for resin cement, since the translucent material benefits from a cement that won’t show through and that bonds tightly to reinforce the ceramic.
- Porcelain-fused-to-metal crowns work well with resin-modified glass ionomer, conventional glass ionomer, or zinc phosphate. The metal substructure provides mechanical retention, so a chemical bond is helpful but less critical.
- Full metal crowns can be cemented with almost any permanent cement, since the metal is strong on its own and the crown’s fit provides good mechanical hold.
Why Leftover Cement Matters
After placing a crown, your dentist removes excess cement that squeezes out from the margins. This step is more important than it sounds. Residual cement left under the gumline can trigger inflammation, gum disease, and, in the case of implant-supported crowns, a condition called peri-implantitis, where the bone around the implant starts to break down. Case reports have documented bone loss and chronic gum irritation directly linked to cement remnants that weren’t fully cleaned up.
Resin cements are particularly tricky to clean because they’re tooth-colored and hard to see against the gum tissue. Some dentists prefer glass ionomer or RMGI for implant crowns partly because excess material is easier to detect and remove.
Sensitivity After Cementation
Some sensitivity after a crown is cemented is normal, especially if the tooth underneath still has a living nerve. The cause depends on the cement type. Glass ionomer cements can irritate the nerve because of their low pH at the moment of placement. Resin cements cause sensitivity for a different reason: the slight shrinkage as they cure can create microscopic gaps that allow fluid movement in the tiny tubes inside your dentin, triggering brief pain with hot or cold.
This sensitivity typically fades within a few days to a couple of weeks. If it persists or worsens, it could signal a problem with the fit, the bite, or the seal. Persistent sharp pain with biting, in particular, suggests the crown may be sitting slightly too high and needs adjustment.