orthodontia vs dental orthopedics

orthodontia and dental orthopedics both are nouns.

Word	Noun	Adjective	Verb	Adverb
orthodontia	Yes	No	No	No
dental orthopedics	Yes	No	No	No

As nouns, orthodontia and dental orthopedics are synonyms defined as:

orthodontia and dental orthopedics: the branch of dentistry dealing with the prevention or correction of irregularities of the teeth

Other synonyms of orthodontia include dental orthopaedics, orthodontics, orthodonture.

orthodontia (noun)	dental orthopedics (noun)
the branch of dentistry dealing with the prevention or correction of irregularities of the teeth	the branch of dentistry dealing with the prevention or correction of irregularities of the teeth