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Ever wondered how dentists hold dental crowns in place? And what about braces? How do they remain in place? The answer is best defined in two words – dental cement and liners. So, what are they? Which chemical compounds do they contain? And, how do they work? Let’s look into that next.

What are Dental Cement and Liners?

These are chemical substances that bond a dental crown to a tooth. And how are they different? Here’s an illustration. Before placing a top, dentists first prepare the tooth. And in the cavity, they apply a thin coating to protect against chemical irritation. This is the liner. However, the layer neither insulates against heat or adds mass to the tooth. That is the work of the crown, which is held in place by cement.


permanent crownThere are two types of cement – temporary or permanent. As its name implies, the first is not meant to last, so dentists use it to hold a temporary crown in place. This is the crown that you get while the dentist prepares a permanent one. As you’d expect, it breaks easily. And then there’s the permanent cement, which holds the permanent crown in place.

Types of Permanent Cement

Permanent cement usually contains one of the following chemical compounds, depending on their use.
• Zinc Oxyphosphate
• Zinc Oxide Eugenol
• Zinc Polycarboxylate
• Glass Ionomer
• Resin Modified Glass Ionomer

Types of Liners

As for the liners, they contain the following compounds, depending on their use.
Calcium Hydroxide
• Varnish
• Resins
• Glass Ionomer

How do Cement and Liners Work?

They work through a combination of chemical bonding and compression. Or to put it in another way: When you bite your food or grind your teeth, the crown compresses the cement and liner, forcing all three to bond.

How are Cement and Lines Cured?

They are cured using dental ultraviolet light, glue, or both. The light works well on thin crowns, which it can penetrate; and the glue, on thick crowns. Crowns whose thickness falls in between are cured using both methods.


As you’ve just seen, how dental crowns remain in place is not as puzzling as you thought. Their secrets are the cement and liners holding them in place. And now you know what those are.