orthodontic braces
Refers to the dental appliance used to straighten teeth. Often simply called 矯正装置 in everyday conversation.
Since I got braces, there are more things I have to be careful about when eating.
A broader term for any orthodontic appliance; 歯列矯正器 specifically refers to braces.
Compound of 歯列 (しれつ, 'row of teeth') + 矯正 (きょうせい, 'correction') + 器 (き, 'device').