Is retainer just the name of this kind of stuff?!

Well..........
The first picture is a retainer that helps you when you get your braces off to help retain your teeth. (When you get your braces off make sure to wear your retainer or else you might have to get braces again. Not fun.)

And the second picture is braces or an appliance. If you don't already know the little square things on the teeth are the brackets, the thing that runs through the brackets is the wire, and the little rings around the bracket are ligatures. Those are to hold the wire in place with the brackets.Health Question & Answer

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http://www.johnsdental.com/images/ortho - this image shows an orthodontic appliance called a modified hawley's appliance, it is used as a retainer in finished orthodontic cases using braces. sometimes it is used to also move minor tooth crowdings in children.

http://images.quebarato.com.br/photos/bi - this is a fixed orthodontic appliance, or brackets(braces). its a double tie-wing bracket, with a wire inserted in the slots.
Health Question & Answer

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The first picture is a retainer.
The second picture is braces.Health Question & Answer

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The first one is a Hawley retainer.

The latter is braces.Health Question & Answer

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