A good impression


If you’ve had braces fitted you will have had “impressions” taken of your teeth. The same if you’ve had a mouth guard made or have crowns, veneers or dentures.

The gunk that is squidged into your mouth is called “alginate” (pronounced al-jin-ate). It’s extracted on an industrial scale from brown seaweed such as giant kelp.

When sodium alginate powder is mixed with water, it sets to form a stiff gel. You will have noticed yourself that the stuff is gooey when it goes in but is quite stiff when your dentist takes it out.

The “setting time” depends on temperature. So on a hot day, the alginate may set too quickly before your dentist can get it in your mouth… so may need a second attempt!

Why do we do it?

Impressions allow us to make plaster models of your teeth. These models can be used to plan orthodontic treatment as we can study the teeth in detail (which can be a bit tricky in a live patient sometimes).

If we need to make you a veneer, a dental technician will use the model to make it on. That way, we can be sure that it will fit your teeth perfectly.

Watch this clip to see how we use your impressions to make models of your teeth.